drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/dma-buf.h>
  19 #include <linux/dma-fence.h>
  20 #include <linux/dma-resv.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/export.h>
  23 #include <linux/fs_parser.h>
  24 #include <linux/hid.h>
  25 #include <linux/mm.h>
  26 #include <linux/module.h>
  27 #include <linux/scatterlist.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/uio.h>
  30 #include <linux/vmalloc.h>
  31 #include <asm/unaligned.h>
  32
  33 #include <linux/usb/ccid.h>
  34 #include <linux/usb/composite.h>
  35 #include <linux/usb/functionfs.h>
  36
  37 #include <linux/aio.h>
  38 #include <linux/kthread.h>
  39 #include <linux/poll.h>
  40 #include <linux/eventfd.h>
  41
  42 #include "u_fs.h"
  43 #include "u_f.h"
  44 #include "u_os_desc.h"
  45 #include "configfs.h"
  46
  47 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  48
  49 #define DMABUF_ENQUEUE_TIMEOUT_MS 5000
  50
  51 MODULE_IMPORT_NS(DMA_BUF);
  52
  53 /* Reference counter handling */
  54 static void ffs_data_get(struct ffs_data *ffs);
  55 static void ffs_data_put(struct ffs_data *ffs);
  56 /* Creates new ffs_data object. */
  57 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  58         __attribute__((malloc));
  59
  60 /* Opened counter handling. */
  61 static void ffs_data_opened(struct ffs_data *ffs);
  62 static void ffs_data_closed(struct ffs_data *ffs);
  63
  64 /* Called with ffs->mutex held; take over ownership of data. */
  65 static int __must_check
  66 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  67 static int __must_check
  68 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  69
  70
  71 /* The function structure ***************************************************/
  72
  73 struct ffs_ep;
  74
  75 struct ffs_function {
  76         struct usb_configuration        *conf;
  77         struct usb_gadget               *gadget;
  78         struct ffs_data                 *ffs;
  79
  80         struct ffs_ep                   *eps;
  81         u8                              eps_revmap[16];
  82         short                           *interfaces_nums;
  83
  84         struct usb_function             function;
  85 };
  86
  87
  88 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  89 {
  90         return container_of(f, struct ffs_function, function);
  91 }
  92
  93
  94 static inline enum ffs_setup_state
  95 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  96 {
  97         return (enum ffs_setup_state)
  98                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  99 }
 100
 101
 102 static void ffs_func_eps_disable(struct ffs_function *func);
 103 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 104
 105 static int ffs_func_bind(struct usb_configuration *,
 106                          struct usb_function *);
 107 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 108 static void ffs_func_disable(struct usb_function *);
 109 static int ffs_func_setup(struct usb_function *,
 110                           const struct usb_ctrlrequest *);
 111 static bool ffs_func_req_match(struct usb_function *,
 112                                const struct usb_ctrlrequest *,
 113                                bool config0);
 114 static void ffs_func_suspend(struct usb_function *);
 115 static void ffs_func_resume(struct usb_function *);
 116
 117
 118 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 119 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 120
 121
 122 /* The endpoints structures *************************************************/
 123
 124 struct ffs_ep {
 125         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 126         struct usb_request              *req;   /* P: epfile->mutex */
 127
 128         /* [0]: full speed, [1]: high speed, [2]: super speed */
 129         struct usb_endpoint_descriptor  *descs[3];
 130
 131         u8                              num;
 132 };
 133
 134 struct ffs_dmabuf_priv {
 135         struct list_head entry;
 136         struct kref ref;
 137         struct ffs_data *ffs;
 138         struct dma_buf_attachment *attach;
 139         struct sg_table *sgt;
 140         enum dma_data_direction dir;
 141         spinlock_t lock;
 142         u64 context;
 143         struct usb_request *req;        /* P: ffs->eps_lock */
 144         struct usb_ep *ep;              /* P: ffs->eps_lock */
 145 };
 146
 147 struct ffs_dma_fence {
 148         struct dma_fence base;
 149         struct ffs_dmabuf_priv *priv;
 150         struct work_struct work;
 151 };
 152
 153 struct ffs_epfile {
 154         /* Protects ep->ep and ep->req. */
 155         struct mutex                    mutex;
 156
 157         struct ffs_data                 *ffs;
 158         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 159
 160         struct dentry                   *dentry;
 161
 162         /*
 163          * Buffer for holding data from partial reads which may happen since
 164          * we’re rounding user read requests to a multiple of a max packet size.
 165          *
 166          * The pointer is initialised with NULL value and may be set by
 167          * __ffs_epfile_read_data function to point to a temporary buffer.
 168          *
 169          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 170          * data from said buffer and eventually free it.  Importantly, while the
 171          * function is using the buffer, it sets the pointer to NULL.  This is
 172          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 173          * can never run concurrently (they are synchronised by epfile->mutex)
 174          * so the latter will not assign a new value to the pointer.
 175          *
 176          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 177          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 178          * value is crux of the synchronisation between ffs_func_eps_disable and
 179          * __ffs_epfile_read_data.
 180          *
 181          * Once __ffs_epfile_read_data is about to finish it will try to set the
 182          * pointer back to its old value (as described above), but seeing as the
 183          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 184          * the buffer.
 185          *
 186          * == State transitions ==
 187          *
 188          * • ptr == NULL:  (initial state)
 189          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 190          *   ◦ __ffs_epfile_read_buffered:    nop
 191          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 192          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 193          * • ptr == DROP:
 194          *   ◦ __ffs_epfile_read_buffer_free: nop
 195          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 196          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 197          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 198          * • ptr == buf:
 199          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 200          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 201          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 202          *                                    is always called first
 203          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 204          * • ptr == NULL and reading:
 205          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 206          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 207          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 208          *   ◦ reading finishes and …
 209          *     … all data read:               free buf, go to ptr == NULL
 210          *     … otherwise:                   go to ptr == buf and reading
 211          * • ptr == DROP and reading:
 212          *   ◦ __ffs_epfile_read_buffer_free: nop
 213          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 214          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 215          *   ◦ reading finishes:              free buf, go to ptr == DROP
 216          */
 217         struct ffs_buffer               *read_buffer;
 218 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 219
 220         char                            name[5];
 221
 222         unsigned char                   in;     /* P: ffs->eps_lock */
 223         unsigned char                   isoc;   /* P: ffs->eps_lock */
 224
 225         unsigned char                   _pad;
 226
 227         /* Protects dmabufs */
 228         struct mutex                    dmabufs_mutex;
 229         struct list_head                dmabufs; /* P: dmabufs_mutex */
 230         atomic_t                        seqno;
 231 };
 232
 233 struct ffs_buffer {
 234         size_t length;
 235         char *data;
 236         char storage[] __counted_by(length);
 237 };
 238
 239 /*  ffs_io_data structure ***************************************************/
 240
 241 struct ffs_io_data {
 242         bool aio;
 243         bool read;
 244
 245         struct kiocb *kiocb;
 246         struct iov_iter data;
 247         const void *to_free;
 248         char *buf;
 249
 250         struct mm_struct *mm;
 251         struct work_struct work;
 252
 253         struct usb_ep *ep;
 254         struct usb_request *req;
 255         struct sg_table sgt;
 256         bool use_sg;
 257
 258         struct ffs_data *ffs;
 259
 260         int status;
 261         struct completion done;
 262 };
 263
 264 struct ffs_desc_helper {
 265         struct ffs_data *ffs;
 266         unsigned interfaces_count;
 267         unsigned eps_count;
 268 };
 269
 270 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 271 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 272
 273 static struct dentry *
 274 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 275                    const struct file_operations *fops);
 276
 277 /* Devices management *******************************************************/
 278
 279 DEFINE_MUTEX(ffs_lock);
 280 EXPORT_SYMBOL_GPL(ffs_lock);
 281
 282 static struct ffs_dev *_ffs_find_dev(const char *name);
 283 static struct ffs_dev *_ffs_alloc_dev(void);
 284 static void _ffs_free_dev(struct ffs_dev *dev);
 285 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 286 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 287 static int ffs_ready(struct ffs_data *ffs);
 288 static void ffs_closed(struct ffs_data *ffs);
 289
 290 /* Misc helper functions ****************************************************/
 291
 292 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 293         __attribute__((warn_unused_result, nonnull));
 294 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 295         __attribute__((warn_unused_result, nonnull));
 296
 297
 298 /* Control file aka ep0 *****************************************************/
 299
 300 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 301 {
 302         struct ffs_data *ffs = req->context;
 303
 304         complete(&ffs->ep0req_completion);
 305 }
 306
 307 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 308         __releases(&ffs->ev.waitq.lock)
 309 {
 310         struct usb_request *req = ffs->ep0req;
 311         int ret;
 312
 313         if (!req) {
 314                 spin_unlock_irq(&ffs->ev.waitq.lock);
 315                 return -EINVAL;
 316         }
 317
 318         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 319
 320         spin_unlock_irq(&ffs->ev.waitq.lock);
 321
 322         req->buf      = data;
 323         req->length   = len;
 324
 325         /*
 326          * UDC layer requires to provide a buffer even for ZLP, but should
 327          * not use it at all. Let's provide some poisoned pointer to catch
 328          * possible bug in the driver.
 329          */
 330         if (req->buf == NULL)
 331                 req->buf = (void *)0xDEADBABE;
 332
 333         reinit_completion(&ffs->ep0req_completion);
 334
 335         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 336         if (ret < 0)
 337                 return ret;
 338
 339         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 340         if (ret) {
 341                 usb_ep_dequeue(ffs->gadget->ep0, req);
 342                 return -EINTR;
 343         }
 344
 345         ffs->setup_state = FFS_NO_SETUP;
 346         return req->status ? req->status : req->actual;
 347 }
 348
 349 static int __ffs_ep0_stall(struct ffs_data *ffs)
 350 {
 351         if (ffs->ev.can_stall) {
 352                 pr_vdebug("ep0 stall\n");
 353                 usb_ep_set_halt(ffs->gadget->ep0);
 354                 ffs->setup_state = FFS_NO_SETUP;
 355                 return -EL2HLT;
 356         } else {
 357                 pr_debug("bogus ep0 stall!\n");
 358                 return -ESRCH;
 359         }
 360 }
 361
 362 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 363                              size_t len, loff_t *ptr)
 364 {
 365         struct ffs_data *ffs = file->private_data;
 366         ssize_t ret;
 367         char *data;
 368
 369         /* Fast check if setup was canceled */
 370         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 371                 return -EIDRM;
 372
 373         /* Acquire mutex */
 374         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 375         if (ret < 0)
 376                 return ret;
 377
 378         /* Check state */
 379         switch (ffs->state) {
 380         case FFS_READ_DESCRIPTORS:
 381         case FFS_READ_STRINGS:
 382                 /* Copy data */
 383                 if (len < 16) {
 384                         ret = -EINVAL;
 385                         break;
 386                 }
 387
 388                 data = ffs_prepare_buffer(buf, len);
 389                 if (IS_ERR(data)) {
 390                         ret = PTR_ERR(data);
 391                         break;
 392                 }
 393
 394                 /* Handle data */
 395                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 396                         pr_info("read descriptors\n");
 397                         ret = __ffs_data_got_descs(ffs, data, len);
 398                         if (ret < 0)
 399                                 break;
 400
 401                         ffs->state = FFS_READ_STRINGS;
 402                         ret = len;
 403                 } else {
 404                         pr_info("read strings\n");
 405                         ret = __ffs_data_got_strings(ffs, data, len);
 406                         if (ret < 0)
 407                                 break;
 408
 409                         ret = ffs_epfiles_create(ffs);
 410                         if (ret) {
 411                                 ffs->state = FFS_CLOSING;
 412                                 break;
 413                         }
 414
 415                         ffs->state = FFS_ACTIVE;
 416                         mutex_unlock(&ffs->mutex);
 417
 418                         ret = ffs_ready(ffs);
 419                         if (ret < 0) {
 420                                 ffs->state = FFS_CLOSING;
 421                                 return ret;
 422                         }
 423
 424                         return len;
 425                 }
 426                 break;
 427
 428         case FFS_ACTIVE:
 429                 data = NULL;
 430                 /*
 431                  * We're called from user space, we can use _irq
 432                  * rather then _irqsave
 433                  */
 434                 spin_lock_irq(&ffs->ev.waitq.lock);
 435                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 436                 case FFS_SETUP_CANCELLED:
 437                         ret = -EIDRM;
 438                         goto done_spin;
 439
 440                 case FFS_NO_SETUP:
 441                         ret = -ESRCH;
 442                         goto done_spin;
 443
 444                 case FFS_SETUP_PENDING:
 445                         break;
 446                 }
 447
 448                 /* FFS_SETUP_PENDING */
 449                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 450                         spin_unlock_irq(&ffs->ev.waitq.lock);
 451                         ret = __ffs_ep0_stall(ffs);
 452                         break;
 453                 }
 454
 455                 /* FFS_SETUP_PENDING and not stall */
 456                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 457
 458                 spin_unlock_irq(&ffs->ev.waitq.lock);
 459
 460                 data = ffs_prepare_buffer(buf, len);
 461                 if (IS_ERR(data)) {
 462                         ret = PTR_ERR(data);
 463                         break;
 464                 }
 465
 466                 spin_lock_irq(&ffs->ev.waitq.lock);
 467
 468                 /*
 469                  * We are guaranteed to be still in FFS_ACTIVE state
 470                  * but the state of setup could have changed from
 471                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 472                  * to check for that.  If that happened we copied data
 473                  * from user space in vain but it's unlikely.
 474                  *
 475                  * For sure we are not in FFS_NO_SETUP since this is
 476                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 477                  * transition can be performed and it's protected by
 478                  * mutex.
 479                  */
 480                 if (ffs_setup_state_clear_cancelled(ffs) ==
 481                     FFS_SETUP_CANCELLED) {
 482                         ret = -EIDRM;
 483 done_spin:
 484                         spin_unlock_irq(&ffs->ev.waitq.lock);
 485                 } else {
 486                         /* unlocks spinlock */
 487                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 488                 }
 489                 kfree(data);
 490                 break;
 491
 492         default:
 493                 ret = -EBADFD;
 494                 break;
 495         }
 496
 497         mutex_unlock(&ffs->mutex);
 498         return ret;
 499 }
 500
 501 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 502 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 503                                      size_t n)
 504         __releases(&ffs->ev.waitq.lock)
 505 {
 506         /*
 507          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 508          * size of ffs->ev.types array (which is four) so that's how much space
 509          * we reserve.
 510          */
 511         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 512         const size_t size = n * sizeof *events;
 513         unsigned i = 0;
 514
 515         memset(events, 0, size);
 516
 517         do {
 518                 events[i].type = ffs->ev.types[i];
 519                 if (events[i].type == FUNCTIONFS_SETUP) {
 520                         events[i].u.setup = ffs->ev.setup;
 521                         ffs->setup_state = FFS_SETUP_PENDING;
 522                 }
 523         } while (++i < n);
 524
 525         ffs->ev.count -= n;
 526         if (ffs->ev.count)
 527                 memmove(ffs->ev.types, ffs->ev.types + n,
 528                         ffs->ev.count * sizeof *ffs->ev.types);
 529
 530         spin_unlock_irq(&ffs->ev.waitq.lock);
 531         mutex_unlock(&ffs->mutex);
 532
 533         return copy_to_user(buf, events, size) ? -EFAULT : size;
 534 }
 535
 536 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 537                             size_t len, loff_t *ptr)
 538 {
 539         struct ffs_data *ffs = file->private_data;
 540         char *data = NULL;
 541         size_t n;
 542         int ret;
 543
 544         /* Fast check if setup was canceled */
 545         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 546                 return -EIDRM;
 547
 548         /* Acquire mutex */
 549         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 550         if (ret < 0)
 551                 return ret;
 552
 553         /* Check state */
 554         if (ffs->state != FFS_ACTIVE) {
 555                 ret = -EBADFD;
 556                 goto done_mutex;
 557         }
 558
 559         /*
 560          * We're called from user space, we can use _irq rather then
 561          * _irqsave
 562          */
 563         spin_lock_irq(&ffs->ev.waitq.lock);
 564
 565         switch (ffs_setup_state_clear_cancelled(ffs)) {
 566         case FFS_SETUP_CANCELLED:
 567                 ret = -EIDRM;
 568                 break;
 569
 570         case FFS_NO_SETUP:
 571                 n = len / sizeof(struct usb_functionfs_event);
 572                 if (!n) {
 573                         ret = -EINVAL;
 574                         break;
 575                 }
 576
 577                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 578                         ret = -EAGAIN;
 579                         break;
 580                 }
 581
 582                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 583                                                         ffs->ev.count)) {
 584                         ret = -EINTR;
 585                         break;
 586                 }
 587
 588                 /* unlocks spinlock */
 589                 return __ffs_ep0_read_events(ffs, buf,
 590                                              min(n, (size_t)ffs->ev.count));
 591
 592         case FFS_SETUP_PENDING:
 593                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 594                         spin_unlock_irq(&ffs->ev.waitq.lock);
 595                         ret = __ffs_ep0_stall(ffs);
 596                         goto done_mutex;
 597                 }
 598
 599                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 600
 601                 spin_unlock_irq(&ffs->ev.waitq.lock);
 602
 603                 if (len) {
 604                         data = kmalloc(len, GFP_KERNEL);
 605                         if (!data) {
 606                                 ret = -ENOMEM;
 607                                 goto done_mutex;
 608                         }
 609                 }
 610
 611                 spin_lock_irq(&ffs->ev.waitq.lock);
 612
 613                 /* See ffs_ep0_write() */
 614                 if (ffs_setup_state_clear_cancelled(ffs) ==
 615                     FFS_SETUP_CANCELLED) {
 616                         ret = -EIDRM;
 617                         break;
 618                 }
 619
 620                 /* unlocks spinlock */
 621                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 622                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 623                         ret = -EFAULT;
 624                 goto done_mutex;
 625
 626         default:
 627                 ret = -EBADFD;
 628                 break;
 629         }
 630
 631         spin_unlock_irq(&ffs->ev.waitq.lock);
 632 done_mutex:
 633         mutex_unlock(&ffs->mutex);
 634         kfree(data);
 635         return ret;
 636 }
 637
 638 static int ffs_ep0_open(struct inode *inode, struct file *file)
 639 {
 640         struct ffs_data *ffs = inode->i_private;
 641
 642         if (ffs->state == FFS_CLOSING)
 643                 return -EBUSY;
 644
 645         file->private_data = ffs;
 646         ffs_data_opened(ffs);
 647
 648         return stream_open(inode, file);
 649 }
 650
 651 static int ffs_ep0_release(struct inode *inode, struct file *file)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654
 655         ffs_data_closed(ffs);
 656
 657         return 0;
 658 }
 659
 660 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 661 {
 662         struct ffs_data *ffs = file->private_data;
 663         struct usb_gadget *gadget = ffs->gadget;
 664         long ret;
 665
 666         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 667                 struct ffs_function *func = ffs->func;
 668                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 669         } else if (gadget && gadget->ops->ioctl) {
 670                 ret = gadget->ops->ioctl(gadget, code, value);
 671         } else {
 672                 ret = -ENOTTY;
 673         }
 674
 675         return ret;
 676 }
 677
 678 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 679 {
 680         struct ffs_data *ffs = file->private_data;
 681         __poll_t mask = EPOLLWRNORM;
 682         int ret;
 683
 684         poll_wait(file, &ffs->ev.waitq, wait);
 685
 686         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 687         if (ret < 0)
 688                 return mask;
 689
 690         switch (ffs->state) {
 691         case FFS_READ_DESCRIPTORS:
 692         case FFS_READ_STRINGS:
 693                 mask |= EPOLLOUT;
 694                 break;
 695
 696         case FFS_ACTIVE:
 697                 switch (ffs->setup_state) {
 698                 case FFS_NO_SETUP:
 699                         if (ffs->ev.count)
 700                                 mask |= EPOLLIN;
 701                         break;
 702
 703                 case FFS_SETUP_PENDING:
 704                 case FFS_SETUP_CANCELLED:
 705                         mask |= (EPOLLIN | EPOLLOUT);
 706                         break;
 707                 }
 708                 break;
 709
 710         case FFS_CLOSING:
 711                 break;
 712         case FFS_DEACTIVATED:
 713                 break;
 714         }
 715
 716         mutex_unlock(&ffs->mutex);
 717
 718         return mask;
 719 }
 720
 721 static const struct file_operations ffs_ep0_operations = {
 722         .llseek =       no_llseek,
 723
 724         .open =         ffs_ep0_open,
 725         .write =        ffs_ep0_write,
 726         .read =         ffs_ep0_read,
 727         .release =      ffs_ep0_release,
 728         .unlocked_ioctl =       ffs_ep0_ioctl,
 729         .poll =         ffs_ep0_poll,
 730 };
 731
 732
 733 /* "Normal" endpoints operations ********************************************/
 734
 735 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 736 {
 737         struct ffs_io_data *io_data = req->context;
 738
 739         if (req->status)
 740                 io_data->status = req->status;
 741         else
 742                 io_data->status = req->actual;
 743
 744         complete(&io_data->done);
 745 }
 746
 747 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 748 {
 749         ssize_t ret = copy_to_iter(data, data_len, iter);
 750         if (ret == data_len)
 751                 return ret;
 752
 753         if (iov_iter_count(iter))
 754                 return -EFAULT;
 755
 756         /*
 757          * Dear user space developer!
 758          *
 759          * TL;DR: To stop getting below error message in your kernel log, change
 760          * user space code using functionfs to align read buffers to a max
 761          * packet size.
 762          *
 763          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 764          * packet size.  When unaligned buffer is passed to functionfs, it
 765          * internally uses a larger, aligned buffer so that such UDCs are happy.
 766          *
 767          * Unfortunately, this means that host may send more data than was
 768          * requested in read(2) system call.  f_fs doesn’t know what to do with
 769          * that excess data so it simply drops it.
 770          *
 771          * Was the buffer aligned in the first place, no such problem would
 772          * happen.
 773          *
 774          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 775          * by splitting a request into multiple parts.  This splitting may still
 776          * be a problem though so it’s likely best to align the buffer
 777          * regardless of it being AIO or not..
 778          *
 779          * This only affects OUT endpoints, i.e. reading data with a read(2),
 780          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 781          * affected.
 782          */
 783         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 784                "Align read buffer size to max packet size to avoid the problem.\n",
 785                data_len, ret);
 786
 787         return ret;
 788 }
 789
 790 /*
 791  * allocate a virtually contiguous buffer and create a scatterlist describing it
 792  * @sg_table    - pointer to a place to be filled with sg_table contents
 793  * @size        - required buffer size
 794  */
 795 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 796 {
 797         struct page **pages;
 798         void *vaddr, *ptr;
 799         unsigned int n_pages;
 800         int i;
 801
 802         vaddr = vmalloc(sz);
 803         if (!vaddr)
 804                 return NULL;
 805
 806         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 807         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 808         if (!pages) {
 809                 vfree(vaddr);
 810
 811                 return NULL;
 812         }
 813         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 814                 pages[i] = vmalloc_to_page(ptr);
 815
 816         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 817                 kvfree(pages);
 818                 vfree(vaddr);
 819
 820                 return NULL;
 821         }
 822         kvfree(pages);
 823
 824         return vaddr;
 825 }
 826
 827 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 828         size_t data_len)
 829 {
 830         if (io_data->use_sg)
 831                 return ffs_build_sg_list(&io_data->sgt, data_len);
 832
 833         return kmalloc(data_len, GFP_KERNEL);
 834 }
 835
 836 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 837 {
 838         if (!io_data->buf)
 839                 return;
 840
 841         if (io_data->use_sg) {
 842                 sg_free_table(&io_data->sgt);
 843                 vfree(io_data->buf);
 844         } else {
 845                 kfree(io_data->buf);
 846         }
 847 }
 848
 849 static void ffs_user_copy_worker(struct work_struct *work)
 850 {
 851         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 852                                                    work);
 853         int ret = io_data->status;
 854         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 855         unsigned long flags;
 856
 857         if (io_data->read && ret > 0) {
 858                 kthread_use_mm(io_data->mm);
 859                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 860                 kthread_unuse_mm(io_data->mm);
 861         }
 862
 863         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 864
 865         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 866                 eventfd_signal(io_data->ffs->ffs_eventfd);
 867
 868         spin_lock_irqsave(&io_data->ffs->eps_lock, flags);
 869         usb_ep_free_request(io_data->ep, io_data->req);
 870         io_data->req = NULL;
 871         spin_unlock_irqrestore(&io_data->ffs->eps_lock, flags);
 872
 873         if (io_data->read)
 874                 kfree(io_data->to_free);
 875         ffs_free_buffer(io_data);
 876         kfree(io_data);
 877 }
 878
 879 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 880                                          struct usb_request *req)
 881 {
 882         struct ffs_io_data *io_data = req->context;
 883         struct ffs_data *ffs = io_data->ffs;
 884
 885         io_data->status = req->status ? req->status : req->actual;
 886
 887         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 888         queue_work(ffs->io_completion_wq, &io_data->work);
 889 }
 890
 891 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 892 {
 893         /*
 894          * See comment in struct ffs_epfile for full read_buffer pointer
 895          * synchronisation story.
 896          */
 897         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 898         if (buf && buf != READ_BUFFER_DROP)
 899                 kfree(buf);
 900 }
 901
 902 /* Assumes epfile->mutex is held. */
 903 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 904                                           struct iov_iter *iter)
 905 {
 906         /*
 907          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 908          * the buffer while we are using it.  See comment in struct ffs_epfile
 909          * for full read_buffer pointer synchronisation story.
 910          */
 911         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 912         ssize_t ret;
 913         if (!buf || buf == READ_BUFFER_DROP)
 914                 return 0;
 915
 916         ret = copy_to_iter(buf->data, buf->length, iter);
 917         if (buf->length == ret) {
 918                 kfree(buf);
 919                 return ret;
 920         }
 921
 922         if (iov_iter_count(iter)) {
 923                 ret = -EFAULT;
 924         } else {
 925                 buf->length -= ret;
 926                 buf->data += ret;
 927         }
 928
 929         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 930                 kfree(buf);
 931
 932         return ret;
 933 }
 934
 935 /* Assumes epfile->mutex is held. */
 936 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 937                                       void *data, int data_len,
 938                                       struct iov_iter *iter)
 939 {
 940         struct ffs_buffer *buf;
 941
 942         ssize_t ret = copy_to_iter(data, data_len, iter);
 943         if (data_len == ret)
 944                 return ret;
 945
 946         if (iov_iter_count(iter))
 947                 return -EFAULT;
 948
 949         /* See ffs_copy_to_iter for more context. */
 950         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 951                 data_len, ret);
 952
 953         data_len -= ret;
 954         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 955         if (!buf)
 956                 return -ENOMEM;
 957         buf->length = data_len;
 958         buf->data = buf->storage;
 959         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 960
 961         /*
 962          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 963          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 964          * in struct ffs_epfile for full read_buffer pointer synchronisation
 965          * story.
 966          */
 967         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 968                 kfree(buf);
 969
 970         return ret;
 971 }
 972
 973 static struct ffs_ep *ffs_epfile_wait_ep(struct file *file)
 974 {
 975         struct ffs_epfile *epfile = file->private_data;
 976         struct ffs_ep *ep;
 977         int ret;
 978
 979         /* Wait for endpoint to be enabled */
 980         ep = epfile->ep;
 981         if (!ep) {
 982                 if (file->f_flags & O_NONBLOCK)
 983                         return ERR_PTR(-EAGAIN);
 984
 985                 ret = wait_event_interruptible(
 986                                 epfile->ffs->wait, (ep = epfile->ep));
 987                 if (ret)
 988                         return ERR_PTR(-EINTR);
 989         }
 990
 991         return ep;
 992 }
 993
 994 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 995 {
 996         struct ffs_epfile *epfile = file->private_data;
 997         struct usb_request *req;
 998         struct ffs_ep *ep;
 999         char *data = NULL;
1000         ssize_t ret, data_len = -EINVAL;
1001         int halt;
1002
1003         /* Are we still active? */
1004         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1005                 return -ENODEV;
1006
1007         ep = ffs_epfile_wait_ep(file);
1008         if (IS_ERR(ep))
1009                 return PTR_ERR(ep);
1010
1011         /* Do we halt? */
1012         halt = (!io_data->read == !epfile->in);
1013         if (halt && epfile->isoc)
1014                 return -EINVAL;
1015
1016         /* We will be using request and read_buffer */
1017         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
1018         if (ret)
1019                 goto error;
1020
1021         /* Allocate & copy */
1022         if (!halt) {
1023                 struct usb_gadget *gadget;
1024
1025                 /*
1026                  * Do we have buffered data from previous partial read?  Check
1027                  * that for synchronous case only because we do not have
1028                  * facility to ‘wake up’ a pending asynchronous read and push
1029                  * buffered data to it which we would need to make things behave
1030                  * consistently.
1031                  */
1032                 if (!io_data->aio && io_data->read) {
1033                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
1034                         if (ret)
1035                                 goto error_mutex;
1036                 }
1037
1038                 /*
1039                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
1040                  * before the waiting completes, so do not assign to 'gadget'
1041                  * earlier
1042                  */
1043                 gadget = epfile->ffs->gadget;
1044
1045                 spin_lock_irq(&epfile->ffs->eps_lock);
1046                 /* In the meantime, endpoint got disabled or changed. */
1047                 if (epfile->ep != ep) {
1048                         ret = -ESHUTDOWN;
1049                         goto error_lock;
1050                 }
1051                 data_len = iov_iter_count(&io_data->data);
1052                 /*
1053                  * Controller may require buffer size to be aligned to
1054                  * maxpacketsize of an out endpoint.
1055                  */
1056                 if (io_data->read)
1057                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1058
1059                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1060                 spin_unlock_irq(&epfile->ffs->eps_lock);
1061
1062                 data = ffs_alloc_buffer(io_data, data_len);
1063                 if (!data) {
1064                         ret = -ENOMEM;
1065                         goto error_mutex;
1066                 }
1067                 if (!io_data->read &&
1068                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1069                         ret = -EFAULT;
1070                         goto error_mutex;
1071                 }
1072         }
1073
1074         spin_lock_irq(&epfile->ffs->eps_lock);
1075
1076         if (epfile->ep != ep) {
1077                 /* In the meantime, endpoint got disabled or changed. */
1078                 ret = -ESHUTDOWN;
1079         } else if (halt) {
1080                 ret = usb_ep_set_halt(ep->ep);
1081                 if (!ret)
1082                         ret = -EBADMSG;
1083         } else if (data_len == -EINVAL) {
1084                 /*
1085                  * Sanity Check: even though data_len can't be used
1086                  * uninitialized at the time I write this comment, some
1087                  * compilers complain about this situation.
1088                  * In order to keep the code clean from warnings, data_len is
1089                  * being initialized to -EINVAL during its declaration, which
1090                  * means we can't rely on compiler anymore to warn no future
1091                  * changes won't result in data_len being used uninitialized.
1092                  * For such reason, we're adding this redundant sanity check
1093                  * here.
1094                  */
1095                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1096                 ret = -EINVAL;
1097         } else if (!io_data->aio) {
1098                 bool interrupted = false;
1099
1100                 req = ep->req;
1101                 if (io_data->use_sg) {
1102                         req->buf = NULL;
1103                         req->sg = io_data->sgt.sgl;
1104                         req->num_sgs = io_data->sgt.nents;
1105                 } else {
1106                         req->buf = data;
1107                         req->num_sgs = 0;
1108                 }
1109                 req->length = data_len;
1110
1111                 io_data->buf = data;
1112
1113                 init_completion(&io_data->done);
1114                 req->context  = io_data;
1115                 req->complete = ffs_epfile_io_complete;
1116
1117                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1118                 if (ret < 0)
1119                         goto error_lock;
1120
1121                 spin_unlock_irq(&epfile->ffs->eps_lock);
1122
1123                 if (wait_for_completion_interruptible(&io_data->done)) {
1124                         spin_lock_irq(&epfile->ffs->eps_lock);
1125                         if (epfile->ep != ep) {
1126                                 ret = -ESHUTDOWN;
1127                                 goto error_lock;
1128                         }
1129                         /*
1130                          * To avoid race condition with ffs_epfile_io_complete,
1131                          * dequeue the request first then check
1132                          * status. usb_ep_dequeue API should guarantee no race
1133                          * condition with req->complete callback.
1134                          */
1135                         usb_ep_dequeue(ep->ep, req);
1136                         spin_unlock_irq(&epfile->ffs->eps_lock);
1137                         wait_for_completion(&io_data->done);
1138                         interrupted = io_data->status < 0;
1139                 }
1140
1141                 if (interrupted)
1142                         ret = -EINTR;
1143                 else if (io_data->read && io_data->status > 0)
1144                         ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1145                                                      &io_data->data);
1146                 else
1147                         ret = io_data->status;
1148                 goto error_mutex;
1149         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1150                 ret = -ENOMEM;
1151         } else {
1152                 if (io_data->use_sg) {
1153                         req->buf = NULL;
1154                         req->sg = io_data->sgt.sgl;
1155                         req->num_sgs = io_data->sgt.nents;
1156                 } else {
1157                         req->buf = data;
1158                         req->num_sgs = 0;
1159                 }
1160                 req->length = data_len;
1161
1162                 io_data->buf = data;
1163                 io_data->ep = ep->ep;
1164                 io_data->req = req;
1165                 io_data->ffs = epfile->ffs;
1166
1167                 req->context  = io_data;
1168                 req->complete = ffs_epfile_async_io_complete;
1169
1170                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1171                 if (ret) {
1172                         io_data->req = NULL;
1173                         usb_ep_free_request(ep->ep, req);
1174                         goto error_lock;
1175                 }
1176
1177                 ret = -EIOCBQUEUED;
1178                 /*
1179                  * Do not kfree the buffer in this function.  It will be freed
1180                  * by ffs_user_copy_worker.
1181                  */
1182                 data = NULL;
1183         }
1184
1185 error_lock:
1186         spin_unlock_irq(&epfile->ffs->eps_lock);
1187 error_mutex:
1188         mutex_unlock(&epfile->mutex);
1189 error:
1190         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1191                 ffs_free_buffer(io_data);
1192         return ret;
1193 }
1194
1195 static int
1196 ffs_epfile_open(struct inode *inode, struct file *file)
1197 {
1198         struct ffs_epfile *epfile = inode->i_private;
1199
1200         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1201                 return -ENODEV;
1202
1203         file->private_data = epfile;
1204         ffs_data_opened(epfile->ffs);
1205
1206         return stream_open(inode, file);
1207 }
1208
1209 static int ffs_aio_cancel(struct kiocb *kiocb)
1210 {
1211         struct ffs_io_data *io_data = kiocb->private;
1212         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1213         unsigned long flags;
1214         int value;
1215
1216         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1217
1218         if (io_data && io_data->ep && io_data->req)
1219                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1220         else
1221                 value = -EINVAL;
1222
1223         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1224
1225         return value;
1226 }
1227
1228 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1229 {
1230         struct ffs_io_data io_data, *p = &io_data;
1231         ssize_t res;
1232
1233         if (!is_sync_kiocb(kiocb)) {
1234                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1235                 if (!p)
1236                         return -ENOMEM;
1237                 p->aio = true;
1238         } else {
1239                 memset(p, 0, sizeof(*p));
1240                 p->aio = false;
1241         }
1242
1243         p->read = false;
1244         p->kiocb = kiocb;
1245         p->data = *from;
1246         p->mm = current->mm;
1247
1248         kiocb->private = p;
1249
1250         if (p->aio)
1251                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1252
1253         res = ffs_epfile_io(kiocb->ki_filp, p);
1254         if (res == -EIOCBQUEUED)
1255                 return res;
1256         if (p->aio)
1257                 kfree(p);
1258         else
1259                 *from = p->data;
1260         return res;
1261 }
1262
1263 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1264 {
1265         struct ffs_io_data io_data, *p = &io_data;
1266         ssize_t res;
1267
1268         if (!is_sync_kiocb(kiocb)) {
1269                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1270                 if (!p)
1271                         return -ENOMEM;
1272                 p->aio = true;
1273         } else {
1274                 memset(p, 0, sizeof(*p));
1275                 p->aio = false;
1276         }
1277
1278         p->read = true;
1279         p->kiocb = kiocb;
1280         if (p->aio) {
1281                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1282                 if (!iter_is_ubuf(&p->data) && !p->to_free) {
1283                         kfree(p);
1284                         return -ENOMEM;
1285                 }
1286         } else {
1287                 p->data = *to;
1288                 p->to_free = NULL;
1289         }
1290         p->mm = current->mm;
1291
1292         kiocb->private = p;
1293
1294         if (p->aio)
1295                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1296
1297         res = ffs_epfile_io(kiocb->ki_filp, p);
1298         if (res == -EIOCBQUEUED)
1299                 return res;
1300
1301         if (p->aio) {
1302                 kfree(p->to_free);
1303                 kfree(p);
1304         } else {
1305                 *to = p->data;
1306         }
1307         return res;
1308 }
1309
1310 static void ffs_dmabuf_release(struct kref *ref)
1311 {
1312         struct ffs_dmabuf_priv *priv = container_of(ref, struct ffs_dmabuf_priv, ref);
1313         struct dma_buf_attachment *attach = priv->attach;
1314         struct dma_buf *dmabuf = attach->dmabuf;
1315
1316         pr_vdebug("FFS DMABUF release\n");
1317         dma_resv_lock(dmabuf->resv, NULL);
1318         dma_buf_unmap_attachment(attach, priv->sgt, priv->dir);
1319         dma_resv_unlock(dmabuf->resv);
1320
1321         dma_buf_detach(attach->dmabuf, attach);
1322         dma_buf_put(dmabuf);
1323         kfree(priv);
1324 }
1325
1326 static void ffs_dmabuf_get(struct dma_buf_attachment *attach)
1327 {
1328         struct ffs_dmabuf_priv *priv = attach->importer_priv;
1329
1330         kref_get(&priv->ref);
1331 }
1332
1333 static void ffs_dmabuf_put(struct dma_buf_attachment *attach)
1334 {
1335         struct ffs_dmabuf_priv *priv = attach->importer_priv;
1336
1337         kref_put(&priv->ref, ffs_dmabuf_release);
1338 }
1339
1340 static int
1341 ffs_epfile_release(struct inode *inode, struct file *file)
1342 {
1343         struct ffs_epfile *epfile = inode->i_private;
1344         struct ffs_dmabuf_priv *priv, *tmp;
1345         struct ffs_data *ffs = epfile->ffs;
1346
1347         mutex_lock(&epfile->dmabufs_mutex);
1348
1349         /* Close all attached DMABUFs */
1350         list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1351                 /* Cancel any pending transfer */
1352                 spin_lock_irq(&ffs->eps_lock);
1353                 if (priv->ep && priv->req)
1354                         usb_ep_dequeue(priv->ep, priv->req);
1355                 spin_unlock_irq(&ffs->eps_lock);
1356
1357                 list_del(&priv->entry);
1358                 ffs_dmabuf_put(priv->attach);
1359         }
1360
1361         mutex_unlock(&epfile->dmabufs_mutex);
1362
1363         __ffs_epfile_read_buffer_free(epfile);
1364         ffs_data_closed(epfile->ffs);
1365
1366         return 0;
1367 }
1368
1369 static void ffs_dmabuf_cleanup(struct work_struct *work)
1370 {
1371         struct ffs_dma_fence *dma_fence =
1372                 container_of(work, struct ffs_dma_fence, work);
1373         struct ffs_dmabuf_priv *priv = dma_fence->priv;
1374         struct dma_buf_attachment *attach = priv->attach;
1375         struct dma_fence *fence = &dma_fence->base;
1376
1377         ffs_dmabuf_put(attach);
1378         dma_fence_put(fence);
1379 }
1380
1381 static void ffs_dmabuf_signal_done(struct ffs_dma_fence *dma_fence, int ret)
1382 {
1383         struct ffs_dmabuf_priv *priv = dma_fence->priv;
1384         struct dma_fence *fence = &dma_fence->base;
1385         bool cookie = dma_fence_begin_signalling();
1386
1387         dma_fence_get(fence);
1388         fence->error = ret;
1389         dma_fence_signal(fence);
1390         dma_fence_end_signalling(cookie);
1391
1392         /*
1393          * The fence will be unref'd in ffs_dmabuf_cleanup.
1394          * It can't be done here, as the unref functions might try to lock
1395          * the resv object, which would deadlock.
1396          */
1397         INIT_WORK(&dma_fence->work, ffs_dmabuf_cleanup);
1398         queue_work(priv->ffs->io_completion_wq, &dma_fence->work);
1399 }
1400
1401 static void ffs_epfile_dmabuf_io_complete(struct usb_ep *ep,
1402                                           struct usb_request *req)
1403 {
1404         pr_vdebug("FFS: DMABUF transfer complete, status=%d\n", req->status);
1405         ffs_dmabuf_signal_done(req->context, req->status);
1406         usb_ep_free_request(ep, req);
1407 }
1408
1409 static const char *ffs_dmabuf_get_driver_name(struct dma_fence *fence)
1410 {
1411         return "functionfs";
1412 }
1413
1414 static const char *ffs_dmabuf_get_timeline_name(struct dma_fence *fence)
1415 {
1416         return "";
1417 }
1418
1419 static void ffs_dmabuf_fence_release(struct dma_fence *fence)
1420 {
1421         struct ffs_dma_fence *dma_fence =
1422                 container_of(fence, struct ffs_dma_fence, base);
1423
1424         kfree(dma_fence);
1425 }
1426
1427 static const struct dma_fence_ops ffs_dmabuf_fence_ops = {
1428         .get_driver_name        = ffs_dmabuf_get_driver_name,
1429         .get_timeline_name      = ffs_dmabuf_get_timeline_name,
1430         .release                = ffs_dmabuf_fence_release,
1431 };
1432
1433 static int ffs_dma_resv_lock(struct dma_buf *dmabuf, bool nonblock)
1434 {
1435         if (!nonblock)
1436                 return dma_resv_lock_interruptible(dmabuf->resv, NULL);
1437
1438         if (!dma_resv_trylock(dmabuf->resv))
1439                 return -EBUSY;
1440
1441         return 0;
1442 }
1443
1444 static struct dma_buf_attachment *
1445 ffs_dmabuf_find_attachment(struct ffs_epfile *epfile, struct dma_buf *dmabuf)
1446 {
1447         struct device *dev = epfile->ffs->gadget->dev.parent;
1448         struct dma_buf_attachment *attach = NULL;
1449         struct ffs_dmabuf_priv *priv;
1450
1451         mutex_lock(&epfile->dmabufs_mutex);
1452
1453         list_for_each_entry(priv, &epfile->dmabufs, entry) {
1454                 if (priv->attach->dev == dev
1455                     && priv->attach->dmabuf == dmabuf) {
1456                         attach = priv->attach;
1457                         break;
1458                 }
1459         }
1460
1461         if (attach)
1462                 ffs_dmabuf_get(attach);
1463
1464         mutex_unlock(&epfile->dmabufs_mutex);
1465
1466         return attach ?: ERR_PTR(-EPERM);
1467 }
1468
1469 static int ffs_dmabuf_attach(struct file *file, int fd)
1470 {
1471         bool nonblock = file->f_flags & O_NONBLOCK;
1472         struct ffs_epfile *epfile = file->private_data;
1473         struct usb_gadget *gadget = epfile->ffs->gadget;
1474         struct dma_buf_attachment *attach;
1475         struct ffs_dmabuf_priv *priv;
1476         enum dma_data_direction dir;
1477         struct sg_table *sg_table;
1478         struct dma_buf *dmabuf;
1479         int err;
1480
1481         if (!gadget || !gadget->sg_supported)
1482                 return -EPERM;
1483
1484         dmabuf = dma_buf_get(fd);
1485         if (IS_ERR(dmabuf))
1486                 return PTR_ERR(dmabuf);
1487
1488         attach = dma_buf_attach(dmabuf, gadget->dev.parent);
1489         if (IS_ERR(attach)) {
1490                 err = PTR_ERR(attach);
1491                 goto err_dmabuf_put;
1492         }
1493
1494         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1495         if (!priv) {
1496                 err = -ENOMEM;
1497                 goto err_dmabuf_detach;
1498         }
1499
1500         dir = epfile->in ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1501
1502         err = ffs_dma_resv_lock(dmabuf, nonblock);
1503         if (err)
1504                 goto err_free_priv;
1505
1506         sg_table = dma_buf_map_attachment(attach, dir);
1507         dma_resv_unlock(dmabuf->resv);
1508
1509         if (IS_ERR(sg_table)) {
1510                 err = PTR_ERR(sg_table);
1511                 goto err_free_priv;
1512         }
1513
1514         attach->importer_priv = priv;
1515
1516         priv->sgt = sg_table;
1517         priv->dir = dir;
1518         priv->ffs = epfile->ffs;
1519         priv->attach = attach;
1520         spin_lock_init(&priv->lock);
1521         kref_init(&priv->ref);
1522         priv->context = dma_fence_context_alloc(1);
1523
1524         mutex_lock(&epfile->dmabufs_mutex);
1525         list_add(&priv->entry, &epfile->dmabufs);
1526         mutex_unlock(&epfile->dmabufs_mutex);
1527
1528         return 0;
1529
1530 err_free_priv:
1531         kfree(priv);
1532 err_dmabuf_detach:
1533         dma_buf_detach(dmabuf, attach);
1534 err_dmabuf_put:
1535         dma_buf_put(dmabuf);
1536
1537         return err;
1538 }
1539
1540 static int ffs_dmabuf_detach(struct file *file, int fd)
1541 {
1542         struct ffs_epfile *epfile = file->private_data;
1543         struct ffs_data *ffs = epfile->ffs;
1544         struct device *dev = ffs->gadget->dev.parent;
1545         struct ffs_dmabuf_priv *priv, *tmp;
1546         struct dma_buf *dmabuf;
1547         int ret = -EPERM;
1548
1549         dmabuf = dma_buf_get(fd);
1550         if (IS_ERR(dmabuf))
1551                 return PTR_ERR(dmabuf);
1552
1553         mutex_lock(&epfile->dmabufs_mutex);
1554
1555         list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1556                 if (priv->attach->dev == dev
1557                     && priv->attach->dmabuf == dmabuf) {
1558                         /* Cancel any pending transfer */
1559                         spin_lock_irq(&ffs->eps_lock);
1560                         if (priv->ep && priv->req)
1561                                 usb_ep_dequeue(priv->ep, priv->req);
1562                         spin_unlock_irq(&ffs->eps_lock);
1563
1564                         list_del(&priv->entry);
1565
1566                         /* Unref the reference from ffs_dmabuf_attach() */
1567                         ffs_dmabuf_put(priv->attach);
1568                         ret = 0;
1569                         break;
1570                 }
1571         }
1572
1573         mutex_unlock(&epfile->dmabufs_mutex);
1574         dma_buf_put(dmabuf);
1575
1576         return ret;
1577 }
1578
1579 static int ffs_dmabuf_transfer(struct file *file,
1580                                const struct usb_ffs_dmabuf_transfer_req *req)
1581 {
1582         bool nonblock = file->f_flags & O_NONBLOCK;
1583         struct ffs_epfile *epfile = file->private_data;
1584         struct dma_buf_attachment *attach;
1585         struct ffs_dmabuf_priv *priv;
1586         struct ffs_dma_fence *fence;
1587         struct usb_request *usb_req;
1588         enum dma_resv_usage resv_dir;
1589         struct dma_buf *dmabuf;
1590         unsigned long timeout;
1591         struct ffs_ep *ep;
1592         bool cookie;
1593         u32 seqno;
1594         long retl;
1595         int ret;
1596
1597         if (req->flags & ~USB_FFS_DMABUF_TRANSFER_MASK)
1598                 return -EINVAL;
1599
1600         dmabuf = dma_buf_get(req->fd);
1601         if (IS_ERR(dmabuf))
1602                 return PTR_ERR(dmabuf);
1603
1604         if (req->length > dmabuf->size || req->length == 0) {
1605                 ret = -EINVAL;
1606                 goto err_dmabuf_put;
1607         }
1608
1609         attach = ffs_dmabuf_find_attachment(epfile, dmabuf);
1610         if (IS_ERR(attach)) {
1611                 ret = PTR_ERR(attach);
1612                 goto err_dmabuf_put;
1613         }
1614
1615         priv = attach->importer_priv;
1616
1617         ep = ffs_epfile_wait_ep(file);
1618         if (IS_ERR(ep)) {
1619                 ret = PTR_ERR(ep);
1620                 goto err_attachment_put;
1621         }
1622
1623         ret = ffs_dma_resv_lock(dmabuf, nonblock);
1624         if (ret)
1625                 goto err_attachment_put;
1626
1627         /* Make sure we don't have writers */
1628         timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS);
1629         retl = dma_resv_wait_timeout(dmabuf->resv,
1630                                      dma_resv_usage_rw(epfile->in),
1631                                      true, timeout);
1632         if (retl == 0)
1633                 retl = -EBUSY;
1634         if (retl < 0) {
1635                 ret = (int)retl;
1636                 goto err_resv_unlock;
1637         }
1638
1639         ret = dma_resv_reserve_fences(dmabuf->resv, 1);
1640         if (ret)
1641                 goto err_resv_unlock;
1642
1643         fence = kmalloc(sizeof(*fence), GFP_KERNEL);
1644         if (!fence) {
1645                 ret = -ENOMEM;
1646                 goto err_resv_unlock;
1647         }
1648
1649         fence->priv = priv;
1650
1651         spin_lock_irq(&epfile->ffs->eps_lock);
1652
1653         /* In the meantime, endpoint got disabled or changed. */
1654         if (epfile->ep != ep) {
1655                 ret = -ESHUTDOWN;
1656                 goto err_fence_put;
1657         }
1658
1659         usb_req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC);
1660         if (!usb_req) {
1661                 ret = -ENOMEM;
1662                 goto err_fence_put;
1663         }
1664
1665         /*
1666          * usb_ep_queue() guarantees that all transfers are processed in the
1667          * order they are enqueued, so we can use a simple incrementing
1668          * sequence number for the dma_fence.
1669          */
1670         seqno = atomic_add_return(1, &epfile->seqno);
1671
1672         dma_fence_init(&fence->base, &ffs_dmabuf_fence_ops,
1673                        &priv->lock, priv->context, seqno);
1674
1675         resv_dir = epfile->in ? DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ;
1676
1677         dma_resv_add_fence(dmabuf->resv, &fence->base, resv_dir);
1678         dma_resv_unlock(dmabuf->resv);
1679
1680         /* Now that the dma_fence is in place, queue the transfer. */
1681
1682         usb_req->length = req->length;
1683         usb_req->buf = NULL;
1684         usb_req->sg = priv->sgt->sgl;
1685         usb_req->num_sgs = sg_nents_for_len(priv->sgt->sgl, req->length);
1686         usb_req->sg_was_mapped = true;
1687         usb_req->context  = fence;
1688         usb_req->complete = ffs_epfile_dmabuf_io_complete;
1689
1690         cookie = dma_fence_begin_signalling();
1691         ret = usb_ep_queue(ep->ep, usb_req, GFP_ATOMIC);
1692         dma_fence_end_signalling(cookie);
1693         if (!ret) {
1694                 priv->req = usb_req;
1695                 priv->ep = ep->ep;
1696         } else {
1697                 pr_warn("FFS: Failed to queue DMABUF: %d\n", ret);
1698                 ffs_dmabuf_signal_done(fence, ret);
1699                 usb_ep_free_request(ep->ep, usb_req);
1700         }
1701
1702         spin_unlock_irq(&epfile->ffs->eps_lock);
1703         dma_buf_put(dmabuf);
1704
1705         return ret;
1706
1707 err_fence_put:
1708         spin_unlock_irq(&epfile->ffs->eps_lock);
1709         dma_fence_put(&fence->base);
1710 err_resv_unlock:
1711         dma_resv_unlock(dmabuf->resv);
1712 err_attachment_put:
1713         ffs_dmabuf_put(attach);
1714 err_dmabuf_put:
1715         dma_buf_put(dmabuf);
1716
1717         return ret;
1718 }
1719
1720 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1721                              unsigned long value)
1722 {
1723         struct ffs_epfile *epfile = file->private_data;
1724         struct ffs_ep *ep;
1725         int ret;
1726
1727         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1728                 return -ENODEV;
1729
1730         switch (code) {
1731         case FUNCTIONFS_DMABUF_ATTACH:
1732         {
1733                 int fd;
1734
1735                 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1736                         ret = -EFAULT;
1737                         break;
1738                 }
1739
1740                 return ffs_dmabuf_attach(file, fd);
1741         }
1742         case FUNCTIONFS_DMABUF_DETACH:
1743         {
1744                 int fd;
1745
1746                 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1747                         ret = -EFAULT;
1748                         break;
1749                 }
1750
1751                 return ffs_dmabuf_detach(file, fd);
1752         }
1753         case FUNCTIONFS_DMABUF_TRANSFER:
1754         {
1755                 struct usb_ffs_dmabuf_transfer_req req;
1756
1757                 if (copy_from_user(&req, (void __user *)value, sizeof(req))) {
1758                         ret = -EFAULT;
1759                         break;
1760                 }
1761
1762                 return ffs_dmabuf_transfer(file, &req);
1763         }
1764         default:
1765                 break;
1766         }
1767
1768         /* Wait for endpoint to be enabled */
1769         ep = ffs_epfile_wait_ep(file);
1770         if (IS_ERR(ep))
1771                 return PTR_ERR(ep);
1772
1773         spin_lock_irq(&epfile->ffs->eps_lock);
1774
1775         /* In the meantime, endpoint got disabled or changed. */
1776         if (epfile->ep != ep) {
1777                 spin_unlock_irq(&epfile->ffs->eps_lock);
1778                 return -ESHUTDOWN;
1779         }
1780
1781         switch (code) {
1782         case FUNCTIONFS_FIFO_STATUS:
1783                 ret = usb_ep_fifo_status(epfile->ep->ep);
1784                 break;
1785         case FUNCTIONFS_FIFO_FLUSH:
1786                 usb_ep_fifo_flush(epfile->ep->ep);
1787                 ret = 0;
1788                 break;
1789         case FUNCTIONFS_CLEAR_HALT:
1790                 ret = usb_ep_clear_halt(epfile->ep->ep);
1791                 break;
1792         case FUNCTIONFS_ENDPOINT_REVMAP:
1793                 ret = epfile->ep->num;
1794                 break;
1795         case FUNCTIONFS_ENDPOINT_DESC:
1796         {
1797                 int desc_idx;
1798                 struct usb_endpoint_descriptor desc1, *desc;
1799
1800                 switch (epfile->ffs->gadget->speed) {
1801                 case USB_SPEED_SUPER:
1802                 case USB_SPEED_SUPER_PLUS:
1803                         desc_idx = 2;
1804                         break;
1805                 case USB_SPEED_HIGH:
1806                         desc_idx = 1;
1807                         break;
1808                 default:
1809                         desc_idx = 0;
1810                 }
1811
1812                 desc = epfile->ep->descs[desc_idx];
1813                 memcpy(&desc1, desc, desc->bLength);
1814
1815                 spin_unlock_irq(&epfile->ffs->eps_lock);
1816                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1817                 if (ret)
1818                         ret = -EFAULT;
1819                 return ret;
1820         }
1821         default:
1822                 ret = -ENOTTY;
1823         }
1824         spin_unlock_irq(&epfile->ffs->eps_lock);
1825
1826         return ret;
1827 }
1828
1829 static const struct file_operations ffs_epfile_operations = {
1830         .llseek =       no_llseek,
1831
1832         .open =         ffs_epfile_open,
1833         .write_iter =   ffs_epfile_write_iter,
1834         .read_iter =    ffs_epfile_read_iter,
1835         .release =      ffs_epfile_release,
1836         .unlocked_ioctl =       ffs_epfile_ioctl,
1837         .compat_ioctl = compat_ptr_ioctl,
1838 };
1839
1840
1841 /* File system and super block operations ***********************************/
1842
1843 /*
1844  * Mounting the file system creates a controller file, used first for
1845  * function configuration then later for event monitoring.
1846  */
1847
1848 static struct inode *__must_check
1849 ffs_sb_make_inode(struct super_block *sb, void *data,
1850                   const struct file_operations *fops,
1851                   const struct inode_operations *iops,
1852                   struct ffs_file_perms *perms)
1853 {
1854         struct inode *inode;
1855
1856         inode = new_inode(sb);
1857
1858         if (inode) {
1859                 struct timespec64 ts = inode_set_ctime_current(inode);
1860
1861                 inode->i_ino     = get_next_ino();
1862                 inode->i_mode    = perms->mode;
1863                 inode->i_uid     = perms->uid;
1864                 inode->i_gid     = perms->gid;
1865                 inode_set_atime_to_ts(inode, ts);
1866                 inode_set_mtime_to_ts(inode, ts);
1867                 inode->i_private = data;
1868                 if (fops)
1869                         inode->i_fop = fops;
1870                 if (iops)
1871                         inode->i_op  = iops;
1872         }
1873
1874         return inode;
1875 }
1876
1877 /* Create "regular" file */
1878 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1879                                         const char *name, void *data,
1880                                         const struct file_operations *fops)
1881 {
1882         struct ffs_data *ffs = sb->s_fs_info;
1883         struct dentry   *dentry;
1884         struct inode    *inode;
1885
1886         dentry = d_alloc_name(sb->s_root, name);
1887         if (!dentry)
1888                 return NULL;
1889
1890         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1891         if (!inode) {
1892                 dput(dentry);
1893                 return NULL;
1894         }
1895
1896         d_add(dentry, inode);
1897         return dentry;
1898 }
1899
1900 /* Super block */
1901 static const struct super_operations ffs_sb_operations = {
1902         .statfs =       simple_statfs,
1903         .drop_inode =   generic_delete_inode,
1904 };
1905
1906 struct ffs_sb_fill_data {
1907         struct ffs_file_perms perms;
1908         umode_t root_mode;
1909         const char *dev_name;
1910         bool no_disconnect;
1911         struct ffs_data *ffs_data;
1912 };
1913
1914 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1915 {
1916         struct ffs_sb_fill_data *data = fc->fs_private;
1917         struct inode    *inode;
1918         struct ffs_data *ffs = data->ffs_data;
1919
1920         ffs->sb              = sb;
1921         data->ffs_data       = NULL;
1922         sb->s_fs_info        = ffs;
1923         sb->s_blocksize      = PAGE_SIZE;
1924         sb->s_blocksize_bits = PAGE_SHIFT;
1925         sb->s_magic          = FUNCTIONFS_MAGIC;
1926         sb->s_op             = &ffs_sb_operations;
1927         sb->s_time_gran      = 1;
1928
1929         /* Root inode */
1930         data->perms.mode = data->root_mode;
1931         inode = ffs_sb_make_inode(sb, NULL,
1932                                   &simple_dir_operations,
1933                                   &simple_dir_inode_operations,
1934                                   &data->perms);
1935         sb->s_root = d_make_root(inode);
1936         if (!sb->s_root)
1937                 return -ENOMEM;
1938
1939         /* EP0 file */
1940         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1941                 return -ENOMEM;
1942
1943         return 0;
1944 }
1945
1946 enum {
1947         Opt_no_disconnect,
1948         Opt_rmode,
1949         Opt_fmode,
1950         Opt_mode,
1951         Opt_uid,
1952         Opt_gid,
1953 };
1954
1955 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1956         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1957         fsparam_u32     ("rmode",               Opt_rmode),
1958         fsparam_u32     ("fmode",               Opt_fmode),
1959         fsparam_u32     ("mode",                Opt_mode),
1960         fsparam_u32     ("uid",                 Opt_uid),
1961         fsparam_u32     ("gid",                 Opt_gid),
1962         {}
1963 };
1964
1965 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1966 {
1967         struct ffs_sb_fill_data *data = fc->fs_private;
1968         struct fs_parse_result result;
1969         int opt;
1970
1971         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1972         if (opt < 0)
1973                 return opt;
1974
1975         switch (opt) {
1976         case Opt_no_disconnect:
1977                 data->no_disconnect = result.boolean;
1978                 break;
1979         case Opt_rmode:
1980                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1981                 break;
1982         case Opt_fmode:
1983                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1984                 break;
1985         case Opt_mode:
1986                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1987                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1988                 break;
1989
1990         case Opt_uid:
1991                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1992                 if (!uid_valid(data->perms.uid))
1993                         goto unmapped_value;
1994                 break;
1995         case Opt_gid:
1996                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1997                 if (!gid_valid(data->perms.gid))
1998                         goto unmapped_value;
1999                 break;
2000
2001         default:
2002                 return -ENOPARAM;
2003         }
2004
2005         return 0;
2006
2007 unmapped_value:
2008         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
2009 }
2010
2011 /*
2012  * Set up the superblock for a mount.
2013  */
2014 static int ffs_fs_get_tree(struct fs_context *fc)
2015 {
2016         struct ffs_sb_fill_data *ctx = fc->fs_private;
2017         struct ffs_data *ffs;
2018         int ret;
2019
2020         if (!fc->source)
2021                 return invalf(fc, "No source specified");
2022
2023         ffs = ffs_data_new(fc->source);
2024         if (!ffs)
2025                 return -ENOMEM;
2026         ffs->file_perms = ctx->perms;
2027         ffs->no_disconnect = ctx->no_disconnect;
2028
2029         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
2030         if (!ffs->dev_name) {
2031                 ffs_data_put(ffs);
2032                 return -ENOMEM;
2033         }
2034
2035         ret = ffs_acquire_dev(ffs->dev_name, ffs);
2036         if (ret) {
2037                 ffs_data_put(ffs);
2038                 return ret;
2039         }
2040
2041         ctx->ffs_data = ffs;
2042         return get_tree_nodev(fc, ffs_sb_fill);
2043 }
2044
2045 static void ffs_fs_free_fc(struct fs_context *fc)
2046 {
2047         struct ffs_sb_fill_data *ctx = fc->fs_private;
2048
2049         if (ctx) {
2050                 if (ctx->ffs_data) {
2051                         ffs_data_put(ctx->ffs_data);
2052                 }
2053
2054                 kfree(ctx);
2055         }
2056 }
2057
2058 static const struct fs_context_operations ffs_fs_context_ops = {
2059         .free           = ffs_fs_free_fc,
2060         .parse_param    = ffs_fs_parse_param,
2061         .get_tree       = ffs_fs_get_tree,
2062 };
2063
2064 static int ffs_fs_init_fs_context(struct fs_context *fc)
2065 {
2066         struct ffs_sb_fill_data *ctx;
2067
2068         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
2069         if (!ctx)
2070                 return -ENOMEM;
2071
2072         ctx->perms.mode = S_IFREG | 0600;
2073         ctx->perms.uid = GLOBAL_ROOT_UID;
2074         ctx->perms.gid = GLOBAL_ROOT_GID;
2075         ctx->root_mode = S_IFDIR | 0500;
2076         ctx->no_disconnect = false;
2077
2078         fc->fs_private = ctx;
2079         fc->ops = &ffs_fs_context_ops;
2080         return 0;
2081 }
2082
2083 static void
2084 ffs_fs_kill_sb(struct super_block *sb)
2085 {
2086         kill_litter_super(sb);
2087         if (sb->s_fs_info)
2088                 ffs_data_closed(sb->s_fs_info);
2089 }
2090
2091 static struct file_system_type ffs_fs_type = {
2092         .owner          = THIS_MODULE,
2093         .name           = "functionfs",
2094         .init_fs_context = ffs_fs_init_fs_context,
2095         .parameters     = ffs_fs_fs_parameters,
2096         .kill_sb        = ffs_fs_kill_sb,
2097 };
2098 MODULE_ALIAS_FS("functionfs");
2099
2100
2101 /* Driver's main init/cleanup functions *************************************/
2102
2103 static int functionfs_init(void)
2104 {
2105         int ret;
2106
2107         ret = register_filesystem(&ffs_fs_type);
2108         if (!ret)
2109                 pr_info("file system registered\n");
2110         else
2111                 pr_err("failed registering file system (%d)\n", ret);
2112
2113         return ret;
2114 }
2115
2116 static void functionfs_cleanup(void)
2117 {
2118         pr_info("unloading\n");
2119         unregister_filesystem(&ffs_fs_type);
2120 }
2121
2122
2123 /* ffs_data and ffs_function construction and destruction code **************/
2124
2125 static void ffs_data_clear(struct ffs_data *ffs);
2126 static void ffs_data_reset(struct ffs_data *ffs);
2127
2128 static void ffs_data_get(struct ffs_data *ffs)
2129 {
2130         refcount_inc(&ffs->ref);
2131 }
2132
2133 static void ffs_data_opened(struct ffs_data *ffs)
2134 {
2135         refcount_inc(&ffs->ref);
2136         if (atomic_add_return(1, &ffs->opened) == 1 &&
2137                         ffs->state == FFS_DEACTIVATED) {
2138                 ffs->state = FFS_CLOSING;
2139                 ffs_data_reset(ffs);
2140         }
2141 }
2142
2143 static void ffs_data_put(struct ffs_data *ffs)
2144 {
2145         if (refcount_dec_and_test(&ffs->ref)) {
2146                 pr_info("%s(): freeing\n", __func__);
2147                 ffs_data_clear(ffs);
2148                 ffs_release_dev(ffs->private_data);
2149                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
2150                        swait_active(&ffs->ep0req_completion.wait) ||
2151                        waitqueue_active(&ffs->wait));
2152                 destroy_workqueue(ffs->io_completion_wq);
2153                 kfree(ffs->dev_name);
2154                 kfree(ffs);
2155         }
2156 }
2157
2158 static void ffs_data_closed(struct ffs_data *ffs)
2159 {
2160         struct ffs_epfile *epfiles;
2161         unsigned long flags;
2162
2163         if (atomic_dec_and_test(&ffs->opened)) {
2164                 if (ffs->no_disconnect) {
2165                         ffs->state = FFS_DEACTIVATED;
2166                         spin_lock_irqsave(&ffs->eps_lock, flags);
2167                         epfiles = ffs->epfiles;
2168                         ffs->epfiles = NULL;
2169                         spin_unlock_irqrestore(&ffs->eps_lock,
2170                                                         flags);
2171
2172                         if (epfiles)
2173                                 ffs_epfiles_destroy(epfiles,
2174                                                  ffs->eps_count);
2175
2176                         if (ffs->setup_state == FFS_SETUP_PENDING)
2177                                 __ffs_ep0_stall(ffs);
2178                 } else {
2179                         ffs->state = FFS_CLOSING;
2180                         ffs_data_reset(ffs);
2181                 }
2182         }
2183         if (atomic_read(&ffs->opened) < 0) {
2184                 ffs->state = FFS_CLOSING;
2185                 ffs_data_reset(ffs);
2186         }
2187
2188         ffs_data_put(ffs);
2189 }
2190
2191 static struct ffs_data *ffs_data_new(const char *dev_name)
2192 {
2193         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
2194         if (!ffs)
2195                 return NULL;
2196
2197         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
2198         if (!ffs->io_completion_wq) {
2199                 kfree(ffs);
2200                 return NULL;
2201         }
2202
2203         refcount_set(&ffs->ref, 1);
2204         atomic_set(&ffs->opened, 0);
2205         ffs->state = FFS_READ_DESCRIPTORS;
2206         mutex_init(&ffs->mutex);
2207         spin_lock_init(&ffs->eps_lock);
2208         init_waitqueue_head(&ffs->ev.waitq);
2209         init_waitqueue_head(&ffs->wait);
2210         init_completion(&ffs->ep0req_completion);
2211
2212         /* XXX REVISIT need to update it in some places, or do we? */
2213         ffs->ev.can_stall = 1;
2214
2215         return ffs;
2216 }
2217
2218 static void ffs_data_clear(struct ffs_data *ffs)
2219 {
2220         struct ffs_epfile *epfiles;
2221         unsigned long flags;
2222
2223         ffs_closed(ffs);
2224
2225         BUG_ON(ffs->gadget);
2226
2227         spin_lock_irqsave(&ffs->eps_lock, flags);
2228         epfiles = ffs->epfiles;
2229         ffs->epfiles = NULL;
2230         spin_unlock_irqrestore(&ffs->eps_lock, flags);
2231
2232         /*
2233          * potential race possible between ffs_func_eps_disable
2234          * & ffs_epfile_release therefore maintaining a local
2235          * copy of epfile will save us from use-after-free.
2236          */
2237         if (epfiles) {
2238                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
2239                 ffs->epfiles = NULL;
2240         }
2241
2242         if (ffs->ffs_eventfd) {
2243                 eventfd_ctx_put(ffs->ffs_eventfd);
2244                 ffs->ffs_eventfd = NULL;
2245         }
2246
2247         kfree(ffs->raw_descs_data);
2248         kfree(ffs->raw_strings);
2249         kfree(ffs->stringtabs);
2250 }
2251
2252 static void ffs_data_reset(struct ffs_data *ffs)
2253 {
2254         ffs_data_clear(ffs);
2255
2256         ffs->raw_descs_data = NULL;
2257         ffs->raw_descs = NULL;
2258         ffs->raw_strings = NULL;
2259         ffs->stringtabs = NULL;
2260
2261         ffs->raw_descs_length = 0;
2262         ffs->fs_descs_count = 0;
2263         ffs->hs_descs_count = 0;
2264         ffs->ss_descs_count = 0;
2265
2266         ffs->strings_count = 0;
2267         ffs->interfaces_count = 0;
2268         ffs->eps_count = 0;
2269
2270         ffs->ev.count = 0;
2271
2272         ffs->state = FFS_READ_DESCRIPTORS;
2273         ffs->setup_state = FFS_NO_SETUP;
2274         ffs->flags = 0;
2275
2276         ffs->ms_os_descs_ext_prop_count = 0;
2277         ffs->ms_os_descs_ext_prop_name_len = 0;
2278         ffs->ms_os_descs_ext_prop_data_len = 0;
2279 }
2280
2281
2282 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
2283 {
2284         struct usb_gadget_strings **lang;
2285         int first_id;
2286
2287         if (WARN_ON(ffs->state != FFS_ACTIVE
2288                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
2289                 return -EBADFD;
2290
2291         first_id = usb_string_ids_n(cdev, ffs->strings_count);
2292         if (first_id < 0)
2293                 return first_id;
2294
2295         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
2296         if (!ffs->ep0req)
2297                 return -ENOMEM;
2298         ffs->ep0req->complete = ffs_ep0_complete;
2299         ffs->ep0req->context = ffs;
2300
2301         lang = ffs->stringtabs;
2302         if (lang) {
2303                 for (; *lang; ++lang) {
2304                         struct usb_string *str = (*lang)->strings;
2305                         int id = first_id;
2306                         for (; str->s; ++id, ++str)
2307                                 str->id = id;
2308                 }
2309         }
2310
2311         ffs->gadget = cdev->gadget;
2312         ffs_data_get(ffs);
2313         return 0;
2314 }
2315
2316 static void functionfs_unbind(struct ffs_data *ffs)
2317 {
2318         if (!WARN_ON(!ffs->gadget)) {
2319                 /* dequeue before freeing ep0req */
2320                 usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
2321                 mutex_lock(&ffs->mutex);
2322                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
2323                 ffs->ep0req = NULL;
2324                 ffs->gadget = NULL;
2325                 clear_bit(FFS_FL_BOUND, &ffs->flags);
2326                 mutex_unlock(&ffs->mutex);
2327                 ffs_data_put(ffs);
2328         }
2329 }
2330
2331 static int ffs_epfiles_create(struct ffs_data *ffs)
2332 {
2333         struct ffs_epfile *epfile, *epfiles;
2334         unsigned i, count;
2335
2336         count = ffs->eps_count;
2337         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
2338         if (!epfiles)
2339                 return -ENOMEM;
2340
2341         epfile = epfiles;
2342         for (i = 1; i <= count; ++i, ++epfile) {
2343                 epfile->ffs = ffs;
2344                 mutex_init(&epfile->mutex);
2345                 mutex_init(&epfile->dmabufs_mutex);
2346                 INIT_LIST_HEAD(&epfile->dmabufs);
2347                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2348                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
2349                 else
2350                         sprintf(epfile->name, "ep%u", i);
2351                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
2352                                                  epfile,
2353                                                  &ffs_epfile_operations);
2354                 if (!epfile->dentry) {
2355                         ffs_epfiles_destroy(epfiles, i - 1);
2356                         return -ENOMEM;
2357                 }
2358         }
2359
2360         ffs->epfiles = epfiles;
2361         return 0;
2362 }
2363
2364 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
2365 {
2366         struct ffs_epfile *epfile = epfiles;
2367
2368         for (; count; --count, ++epfile) {
2369                 BUG_ON(mutex_is_locked(&epfile->mutex));
2370                 if (epfile->dentry) {
2371                         d_delete(epfile->dentry);
2372                         dput(epfile->dentry);
2373                         epfile->dentry = NULL;
2374                 }
2375         }
2376
2377         kfree(epfiles);
2378 }
2379
2380 static void ffs_func_eps_disable(struct ffs_function *func)
2381 {
2382         struct ffs_ep *ep;
2383         struct ffs_epfile *epfile;
2384         unsigned short count;
2385         unsigned long flags;
2386
2387         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2388         count = func->ffs->eps_count;
2389         epfile = func->ffs->epfiles;
2390         ep = func->eps;
2391         while (count--) {
2392                 /* pending requests get nuked */
2393                 if (ep->ep)
2394                         usb_ep_disable(ep->ep);
2395                 ++ep;
2396
2397                 if (epfile) {
2398                         epfile->ep = NULL;
2399                         __ffs_epfile_read_buffer_free(epfile);
2400                         ++epfile;
2401                 }
2402         }
2403         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2404 }
2405
2406 static int ffs_func_eps_enable(struct ffs_function *func)
2407 {
2408         struct ffs_data *ffs;
2409         struct ffs_ep *ep;
2410         struct ffs_epfile *epfile;
2411         unsigned short count;
2412         unsigned long flags;
2413         int ret = 0;
2414
2415         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2416         ffs = func->ffs;
2417         ep = func->eps;
2418         epfile = ffs->epfiles;
2419         count = ffs->eps_count;
2420         while(count--) {
2421                 ep->ep->driver_data = ep;
2422
2423                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
2424                 if (ret) {
2425                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2426                                         __func__, ep->ep->name, ret);
2427                         break;
2428                 }
2429
2430                 ret = usb_ep_enable(ep->ep);
2431                 if (!ret) {
2432                         epfile->ep = ep;
2433                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2434                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2435                 } else {
2436                         break;
2437                 }
2438
2439                 ++ep;
2440                 ++epfile;
2441         }
2442
2443         wake_up_interruptible(&ffs->wait);
2444         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2445
2446         return ret;
2447 }
2448
2449
2450 /* Parsing and building descriptors and strings *****************************/
2451
2452 /*
2453  * This validates if data pointed by data is a valid USB descriptor as
2454  * well as record how many interfaces, endpoints and strings are
2455  * required by given configuration.  Returns address after the
2456  * descriptor or NULL if data is invalid.
2457  */
2458
2459 enum ffs_entity_type {
2460         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2461 };
2462
2463 enum ffs_os_desc_type {
2464         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2465 };
2466
2467 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2468                                    u8 *valuep,
2469                                    struct usb_descriptor_header *desc,
2470                                    void *priv);
2471
2472 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2473                                     struct usb_os_desc_header *h, void *data,
2474                                     unsigned len, void *priv);
2475
2476 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2477                                            ffs_entity_callback entity,
2478                                            void *priv, int *current_class)
2479 {
2480         struct usb_descriptor_header *_ds = (void *)data;
2481         u8 length;
2482         int ret;
2483
2484         /* At least two bytes are required: length and type */
2485         if (len < 2) {
2486                 pr_vdebug("descriptor too short\n");
2487                 return -EINVAL;
2488         }
2489
2490         /* If we have at least as many bytes as the descriptor takes? */
2491         length = _ds->bLength;
2492         if (len < length) {
2493                 pr_vdebug("descriptor longer then available data\n");
2494                 return -EINVAL;
2495         }
2496
2497 #define __entity_check_INTERFACE(val)  1
2498 #define __entity_check_STRING(val)     (val)
2499 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2500 #define __entity(type, val) do {                                        \
2501                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2502                 if (!__entity_check_ ##type(val)) {                     \
2503                         pr_vdebug("invalid entity's value\n");          \
2504                         return -EINVAL;                                 \
2505                 }                                                       \
2506                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2507                 if (ret < 0) {                                          \
2508                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2509                                  (val), ret);                           \
2510                         return ret;                                     \
2511                 }                                                       \
2512         } while (0)
2513
2514         /* Parse descriptor depending on type. */
2515         switch (_ds->bDescriptorType) {
2516         case USB_DT_DEVICE:
2517         case USB_DT_CONFIG:
2518         case USB_DT_STRING:
2519         case USB_DT_DEVICE_QUALIFIER:
2520                 /* function can't have any of those */
2521                 pr_vdebug("descriptor reserved for gadget: %d\n",
2522                       _ds->bDescriptorType);
2523                 return -EINVAL;
2524
2525         case USB_DT_INTERFACE: {
2526                 struct usb_interface_descriptor *ds = (void *)_ds;
2527                 pr_vdebug("interface descriptor\n");
2528                 if (length != sizeof *ds)
2529                         goto inv_length;
2530
2531                 __entity(INTERFACE, ds->bInterfaceNumber);
2532                 if (ds->iInterface)
2533                         __entity(STRING, ds->iInterface);
2534                 *current_class = ds->bInterfaceClass;
2535         }
2536                 break;
2537
2538         case USB_DT_ENDPOINT: {
2539                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2540                 pr_vdebug("endpoint descriptor\n");
2541                 if (length != USB_DT_ENDPOINT_SIZE &&
2542                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2543                         goto inv_length;
2544                 __entity(ENDPOINT, ds->bEndpointAddress);
2545         }
2546                 break;
2547
2548         case USB_TYPE_CLASS | 0x01:
2549                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2550                         pr_vdebug("hid descriptor\n");
2551                         if (length != sizeof(struct hid_descriptor))
2552                                 goto inv_length;
2553                         break;
2554                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2555                         pr_vdebug("ccid descriptor\n");
2556                         if (length != sizeof(struct ccid_descriptor))
2557                                 goto inv_length;
2558                         break;
2559                 } else {
2560                         pr_vdebug("unknown descriptor: %d for class %d\n",
2561                               _ds->bDescriptorType, *current_class);
2562                         return -EINVAL;
2563                 }
2564
2565         case USB_DT_OTG:
2566                 if (length != sizeof(struct usb_otg_descriptor))
2567                         goto inv_length;
2568                 break;
2569
2570         case USB_DT_INTERFACE_ASSOCIATION: {
2571                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2572                 pr_vdebug("interface association descriptor\n");
2573                 if (length != sizeof *ds)
2574                         goto inv_length;
2575                 if (ds->iFunction)
2576                         __entity(STRING, ds->iFunction);
2577         }
2578                 break;
2579
2580         case USB_DT_SS_ENDPOINT_COMP:
2581                 pr_vdebug("EP SS companion descriptor\n");
2582                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2583                         goto inv_length;
2584                 break;
2585
2586         case USB_DT_OTHER_SPEED_CONFIG:
2587         case USB_DT_INTERFACE_POWER:
2588         case USB_DT_DEBUG:
2589         case USB_DT_SECURITY:
2590         case USB_DT_CS_RADIO_CONTROL:
2591                 /* TODO */
2592                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2593                 return -EINVAL;
2594
2595         default:
2596                 /* We should never be here */
2597                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2598                 return -EINVAL;
2599
2600 inv_length:
2601                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2602                           _ds->bLength, _ds->bDescriptorType);
2603                 return -EINVAL;
2604         }
2605
2606 #undef __entity
2607 #undef __entity_check_DESCRIPTOR
2608 #undef __entity_check_INTERFACE
2609 #undef __entity_check_STRING
2610 #undef __entity_check_ENDPOINT
2611
2612         return length;
2613 }
2614
2615 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2616                                      ffs_entity_callback entity, void *priv)
2617 {
2618         const unsigned _len = len;
2619         unsigned long num = 0;
2620         int current_class = -1;
2621
2622         for (;;) {
2623                 int ret;
2624
2625                 if (num == count)
2626                         data = NULL;
2627
2628                 /* Record "descriptor" entity */
2629                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2630                 if (ret < 0) {
2631                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2632                                  num, ret);
2633                         return ret;
2634                 }
2635
2636                 if (!data)
2637                         return _len - len;
2638
2639                 ret = ffs_do_single_desc(data, len, entity, priv,
2640                         &current_class);
2641                 if (ret < 0) {
2642                         pr_debug("%s returns %d\n", __func__, ret);
2643                         return ret;
2644                 }
2645
2646                 len -= ret;
2647                 data += ret;
2648                 ++num;
2649         }
2650 }
2651
2652 static int __ffs_data_do_entity(enum ffs_entity_type type,
2653                                 u8 *valuep, struct usb_descriptor_header *desc,
2654                                 void *priv)
2655 {
2656         struct ffs_desc_helper *helper = priv;
2657         struct usb_endpoint_descriptor *d;
2658
2659         switch (type) {
2660         case FFS_DESCRIPTOR:
2661                 break;
2662
2663         case FFS_INTERFACE:
2664                 /*
2665                  * Interfaces are indexed from zero so if we
2666                  * encountered interface "n" then there are at least
2667                  * "n+1" interfaces.
2668                  */
2669                 if (*valuep >= helper->interfaces_count)
2670                         helper->interfaces_count = *valuep + 1;
2671                 break;
2672
2673         case FFS_STRING:
2674                 /*
2675                  * Strings are indexed from 1 (0 is reserved
2676                  * for languages list)
2677                  */
2678                 if (*valuep > helper->ffs->strings_count)
2679                         helper->ffs->strings_count = *valuep;
2680                 break;
2681
2682         case FFS_ENDPOINT:
2683                 d = (void *)desc;
2684                 helper->eps_count++;
2685                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2686                         return -EINVAL;
2687                 /* Check if descriptors for any speed were already parsed */
2688                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2689                         helper->ffs->eps_addrmap[helper->eps_count] =
2690                                 d->bEndpointAddress;
2691                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2692                                 d->bEndpointAddress)
2693                         return -EINVAL;
2694                 break;
2695         }
2696
2697         return 0;
2698 }
2699
2700 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2701                                    struct usb_os_desc_header *desc)
2702 {
2703         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2704         u16 w_index = le16_to_cpu(desc->wIndex);
2705
2706         if (bcd_version == 0x1) {
2707                 pr_warn("bcdVersion must be 0x0100, stored in Little Endian order. "
2708                         "Userspace driver should be fixed, accepting 0x0001 for compatibility.\n");
2709         } else if (bcd_version != 0x100) {
2710                 pr_vdebug("unsupported os descriptors version: 0x%x\n",
2711                           bcd_version);
2712                 return -EINVAL;
2713         }
2714         switch (w_index) {
2715         case 0x4:
2716                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2717                 break;
2718         case 0x5:
2719                 *next_type = FFS_OS_DESC_EXT_PROP;
2720                 break;
2721         default:
2722                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2723                 return -EINVAL;
2724         }
2725
2726         return sizeof(*desc);
2727 }
2728
2729 /*
2730  * Process all extended compatibility/extended property descriptors
2731  * of a feature descriptor
2732  */
2733 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2734                                               enum ffs_os_desc_type type,
2735                                               u16 feature_count,
2736                                               ffs_os_desc_callback entity,
2737                                               void *priv,
2738                                               struct usb_os_desc_header *h)
2739 {
2740         int ret;
2741         const unsigned _len = len;
2742
2743         /* loop over all ext compat/ext prop descriptors */
2744         while (feature_count--) {
2745                 ret = entity(type, h, data, len, priv);
2746                 if (ret < 0) {
2747                         pr_debug("bad OS descriptor, type: %d\n", type);
2748                         return ret;
2749                 }
2750                 data += ret;
2751                 len -= ret;
2752         }
2753         return _len - len;
2754 }
2755
2756 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2757 static int __must_check ffs_do_os_descs(unsigned count,
2758                                         char *data, unsigned len,
2759                                         ffs_os_desc_callback entity, void *priv)
2760 {
2761         const unsigned _len = len;
2762         unsigned long num = 0;
2763
2764         for (num = 0; num < count; ++num) {
2765                 int ret;
2766                 enum ffs_os_desc_type type;
2767                 u16 feature_count;
2768                 struct usb_os_desc_header *desc = (void *)data;
2769
2770                 if (len < sizeof(*desc))
2771                         return -EINVAL;
2772
2773                 /*
2774                  * Record "descriptor" entity.
2775                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2776                  * Move the data pointer to the beginning of extended
2777                  * compatibilities proper or extended properties proper
2778                  * portions of the data
2779                  */
2780                 if (le32_to_cpu(desc->dwLength) > len)
2781                         return -EINVAL;
2782
2783                 ret = __ffs_do_os_desc_header(&type, desc);
2784                 if (ret < 0) {
2785                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2786                                  num, ret);
2787                         return ret;
2788                 }
2789                 /*
2790                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2791                  */
2792                 feature_count = le16_to_cpu(desc->wCount);
2793                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2794                     (feature_count > 255 || desc->Reserved))
2795                                 return -EINVAL;
2796                 len -= ret;
2797                 data += ret;
2798
2799                 /*
2800                  * Process all function/property descriptors
2801                  * of this Feature Descriptor
2802                  */
2803                 ret = ffs_do_single_os_desc(data, len, type,
2804                                             feature_count, entity, priv, desc);
2805                 if (ret < 0) {
2806                         pr_debug("%s returns %d\n", __func__, ret);
2807                         return ret;
2808                 }
2809
2810                 len -= ret;
2811                 data += ret;
2812         }
2813         return _len - len;
2814 }
2815
2816 /*
2817  * Validate contents of the buffer from userspace related to OS descriptors.
2818  */
2819 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2820                                  struct usb_os_desc_header *h, void *data,
2821                                  unsigned len, void *priv)
2822 {
2823         struct ffs_data *ffs = priv;
2824         u8 length;
2825
2826         switch (type) {
2827         case FFS_OS_DESC_EXT_COMPAT: {
2828                 struct usb_ext_compat_desc *d = data;
2829                 int i;
2830
2831                 if (len < sizeof(*d) ||
2832                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2833                         return -EINVAL;
2834                 if (d->Reserved1 != 1) {
2835                         /*
2836                          * According to the spec, Reserved1 must be set to 1
2837                          * but older kernels incorrectly rejected non-zero
2838                          * values.  We fix it here to avoid returning EINVAL
2839                          * in response to values we used to accept.
2840                          */
2841                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2842                         d->Reserved1 = 1;
2843                 }
2844                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2845                         if (d->Reserved2[i])
2846                                 return -EINVAL;
2847
2848                 length = sizeof(struct usb_ext_compat_desc);
2849         }
2850                 break;
2851         case FFS_OS_DESC_EXT_PROP: {
2852                 struct usb_ext_prop_desc *d = data;
2853                 u32 type, pdl;
2854                 u16 pnl;
2855
2856                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2857                         return -EINVAL;
2858                 length = le32_to_cpu(d->dwSize);
2859                 if (len < length)
2860                         return -EINVAL;
2861                 type = le32_to_cpu(d->dwPropertyDataType);
2862                 if (type < USB_EXT_PROP_UNICODE ||
2863                     type > USB_EXT_PROP_UNICODE_MULTI) {
2864                         pr_vdebug("unsupported os descriptor property type: %d",
2865                                   type);
2866                         return -EINVAL;
2867                 }
2868                 pnl = le16_to_cpu(d->wPropertyNameLength);
2869                 if (length < 14 + pnl) {
2870                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2871                                   length, pnl, type);
2872                         return -EINVAL;
2873                 }
2874                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2875                 if (length != 14 + pnl + pdl) {
2876                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2877                                   length, pnl, pdl, type);
2878                         return -EINVAL;
2879                 }
2880                 ++ffs->ms_os_descs_ext_prop_count;
2881                 /* property name reported to the host as "WCHAR"s */
2882                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2883                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2884         }
2885                 break;
2886         default:
2887                 pr_vdebug("unknown descriptor: %d\n", type);
2888                 return -EINVAL;
2889         }
2890         return length;
2891 }
2892
2893 static int __ffs_data_got_descs(struct ffs_data *ffs,
2894                                 char *const _data, size_t len)
2895 {
2896         char *data = _data, *raw_descs;
2897         unsigned os_descs_count = 0, counts[3], flags;
2898         int ret = -EINVAL, i;
2899         struct ffs_desc_helper helper;
2900
2901         if (get_unaligned_le32(data + 4) != len)
2902                 goto error;
2903
2904         switch (get_unaligned_le32(data)) {
2905         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2906                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2907                 data += 8;
2908                 len  -= 8;
2909                 break;
2910         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2911                 flags = get_unaligned_le32(data + 8);
2912                 ffs->user_flags = flags;
2913                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2914                               FUNCTIONFS_HAS_HS_DESC |
2915                               FUNCTIONFS_HAS_SS_DESC |
2916                               FUNCTIONFS_HAS_MS_OS_DESC |
2917                               FUNCTIONFS_VIRTUAL_ADDR |
2918                               FUNCTIONFS_EVENTFD |
2919                               FUNCTIONFS_ALL_CTRL_RECIP |
2920                               FUNCTIONFS_CONFIG0_SETUP)) {
2921                         ret = -ENOSYS;
2922                         goto error;
2923                 }
2924                 data += 12;
2925                 len  -= 12;
2926                 break;
2927         default:
2928                 goto error;
2929         }
2930
2931         if (flags & FUNCTIONFS_EVENTFD) {
2932                 if (len < 4)
2933                         goto error;
2934                 ffs->ffs_eventfd =
2935                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2936                 if (IS_ERR(ffs->ffs_eventfd)) {
2937                         ret = PTR_ERR(ffs->ffs_eventfd);
2938                         ffs->ffs_eventfd = NULL;
2939                         goto error;
2940                 }
2941                 data += 4;
2942                 len  -= 4;
2943         }
2944
2945         /* Read fs_count, hs_count and ss_count (if present) */
2946         for (i = 0; i < 3; ++i) {
2947                 if (!(flags & (1 << i))) {
2948                         counts[i] = 0;
2949                 } else if (len < 4) {
2950                         goto error;
2951                 } else {
2952                         counts[i] = get_unaligned_le32(data);
2953                         data += 4;
2954                         len  -= 4;
2955                 }
2956         }
2957         if (flags & (1 << i)) {
2958                 if (len < 4) {
2959                         goto error;
2960                 }
2961                 os_descs_count = get_unaligned_le32(data);
2962                 data += 4;
2963                 len -= 4;
2964         }
2965
2966         /* Read descriptors */
2967         raw_descs = data;
2968         helper.ffs = ffs;
2969         for (i = 0; i < 3; ++i) {
2970                 if (!counts[i])
2971                         continue;
2972                 helper.interfaces_count = 0;
2973                 helper.eps_count = 0;
2974                 ret = ffs_do_descs(counts[i], data, len,
2975                                    __ffs_data_do_entity, &helper);
2976                 if (ret < 0)
2977                         goto error;
2978                 if (!ffs->eps_count && !ffs->interfaces_count) {
2979                         ffs->eps_count = helper.eps_count;
2980                         ffs->interfaces_count = helper.interfaces_count;
2981                 } else {
2982                         if (ffs->eps_count != helper.eps_count) {
2983                                 ret = -EINVAL;
2984                                 goto error;
2985                         }
2986                         if (ffs->interfaces_count != helper.interfaces_count) {
2987                                 ret = -EINVAL;
2988                                 goto error;
2989                         }
2990                 }
2991                 data += ret;
2992                 len  -= ret;
2993         }
2994         if (os_descs_count) {
2995                 ret = ffs_do_os_descs(os_descs_count, data, len,
2996                                       __ffs_data_do_os_desc, ffs);
2997                 if (ret < 0)
2998                         goto error;
2999                 data += ret;
3000                 len -= ret;
3001         }
3002
3003         if (raw_descs == data || len) {
3004                 ret = -EINVAL;
3005                 goto error;
3006         }
3007
3008         ffs->raw_descs_data     = _data;
3009         ffs->raw_descs          = raw_descs;
3010         ffs->raw_descs_length   = data - raw_descs;
3011         ffs->fs_descs_count     = counts[0];
3012         ffs->hs_descs_count     = counts[1];
3013         ffs->ss_descs_count     = counts[2];
3014         ffs->ms_os_descs_count  = os_descs_count;
3015
3016         return 0;
3017
3018 error:
3019         kfree(_data);
3020         return ret;
3021 }
3022
3023 static int __ffs_data_got_strings(struct ffs_data *ffs,
3024                                   char *const _data, size_t len)
3025 {
3026         u32 str_count, needed_count, lang_count;
3027         struct usb_gadget_strings **stringtabs, *t;
3028         const char *data = _data;
3029         struct usb_string *s;
3030
3031         if (len < 16 ||
3032             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
3033             get_unaligned_le32(data + 4) != len)
3034                 goto error;
3035         str_count  = get_unaligned_le32(data + 8);
3036         lang_count = get_unaligned_le32(data + 12);
3037
3038         /* if one is zero the other must be zero */
3039         if (!str_count != !lang_count)
3040                 goto error;
3041
3042         /* Do we have at least as many strings as descriptors need? */
3043         needed_count = ffs->strings_count;
3044         if (str_count < needed_count)
3045                 goto error;
3046
3047         /*
3048          * If we don't need any strings just return and free all
3049          * memory.
3050          */
3051         if (!needed_count) {
3052                 kfree(_data);
3053                 return 0;
3054         }
3055
3056         /* Allocate everything in one chunk so there's less maintenance. */
3057         {
3058                 unsigned i = 0;
3059                 vla_group(d);
3060                 vla_item(d, struct usb_gadget_strings *, stringtabs,
3061                         size_add(lang_count, 1));
3062                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
3063                 vla_item(d, struct usb_string, strings,
3064                         size_mul(lang_count, (needed_count + 1)));
3065
3066                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
3067
3068                 if (!vlabuf) {
3069                         kfree(_data);
3070                         return -ENOMEM;
3071                 }
3072
3073                 /* Initialize the VLA pointers */
3074                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3075                 t = vla_ptr(vlabuf, d, stringtab);
3076                 i = lang_count;
3077                 do {
3078                         *stringtabs++ = t++;
3079                 } while (--i);
3080                 *stringtabs = NULL;
3081
3082                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
3083                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3084                 t = vla_ptr(vlabuf, d, stringtab);
3085                 s = vla_ptr(vlabuf, d, strings);
3086         }
3087
3088         /* For each language */
3089         data += 16;
3090         len -= 16;
3091
3092         do { /* lang_count > 0 so we can use do-while */
3093                 unsigned needed = needed_count;
3094                 u32 str_per_lang = str_count;
3095
3096                 if (len < 3)
3097                         goto error_free;
3098                 t->language = get_unaligned_le16(data);
3099                 t->strings  = s;
3100                 ++t;
3101
3102                 data += 2;
3103                 len -= 2;
3104
3105                 /* For each string */
3106                 do { /* str_count > 0 so we can use do-while */
3107                         size_t length = strnlen(data, len);
3108
3109                         if (length == len)
3110                                 goto error_free;
3111
3112                         /*
3113                          * User may provide more strings then we need,
3114                          * if that's the case we simply ignore the
3115                          * rest
3116                          */
3117                         if (needed) {
3118                                 /*
3119                                  * s->id will be set while adding
3120                                  * function to configuration so for
3121                                  * now just leave garbage here.
3122                                  */
3123                                 s->s = data;
3124                                 --needed;
3125                                 ++s;
3126                         }
3127
3128                         data += length + 1;
3129                         len -= length + 1;
3130                 } while (--str_per_lang);
3131
3132                 s->id = 0;   /* terminator */
3133                 s->s = NULL;
3134                 ++s;
3135
3136         } while (--lang_count);
3137
3138         /* Some garbage left? */
3139         if (len)
3140                 goto error_free;
3141
3142         /* Done! */
3143         ffs->stringtabs = stringtabs;
3144         ffs->raw_strings = _data;
3145
3146         return 0;
3147
3148 error_free:
3149         kfree(stringtabs);
3150 error:
3151         kfree(_data);
3152         return -EINVAL;
3153 }
3154
3155
3156 /* Events handling and management *******************************************/
3157
3158 static void __ffs_event_add(struct ffs_data *ffs,
3159                             enum usb_functionfs_event_type type)
3160 {
3161         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
3162         int neg = 0;
3163
3164         /*
3165          * Abort any unhandled setup
3166          *
3167          * We do not need to worry about some cmpxchg() changing value
3168          * of ffs->setup_state without holding the lock because when
3169          * state is FFS_SETUP_PENDING cmpxchg() in several places in
3170          * the source does nothing.
3171          */
3172         if (ffs->setup_state == FFS_SETUP_PENDING)
3173                 ffs->setup_state = FFS_SETUP_CANCELLED;
3174
3175         /*
3176          * Logic of this function guarantees that there are at most four pending
3177          * evens on ffs->ev.types queue.  This is important because the queue
3178          * has space for four elements only and __ffs_ep0_read_events function
3179          * depends on that limit as well.  If more event types are added, those
3180          * limits have to be revisited or guaranteed to still hold.
3181          */
3182         switch (type) {
3183         case FUNCTIONFS_RESUME:
3184                 rem_type2 = FUNCTIONFS_SUSPEND;
3185                 fallthrough;
3186         case FUNCTIONFS_SUSPEND:
3187         case FUNCTIONFS_SETUP:
3188                 rem_type1 = type;
3189                 /* Discard all similar events */
3190                 break;
3191
3192         case FUNCTIONFS_BIND:
3193         case FUNCTIONFS_UNBIND:
3194         case FUNCTIONFS_DISABLE:
3195         case FUNCTIONFS_ENABLE:
3196                 /* Discard everything other then power management. */
3197                 rem_type1 = FUNCTIONFS_SUSPEND;
3198                 rem_type2 = FUNCTIONFS_RESUME;
3199                 neg = 1;
3200                 break;
3201
3202         default:
3203                 WARN(1, "%d: unknown event, this should not happen\n", type);
3204                 return;
3205         }
3206
3207         {
3208                 u8 *ev  = ffs->ev.types, *out = ev;
3209                 unsigned n = ffs->ev.count;
3210                 for (; n; --n, ++ev)
3211                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
3212                                 *out++ = *ev;
3213                         else
3214                                 pr_vdebug("purging event %d\n", *ev);
3215                 ffs->ev.count = out - ffs->ev.types;
3216         }
3217
3218         pr_vdebug("adding event %d\n", type);
3219         ffs->ev.types[ffs->ev.count++] = type;
3220         wake_up_locked(&ffs->ev.waitq);
3221         if (ffs->ffs_eventfd)
3222                 eventfd_signal(ffs->ffs_eventfd);
3223 }
3224
3225 static void ffs_event_add(struct ffs_data *ffs,
3226                           enum usb_functionfs_event_type type)
3227 {
3228         unsigned long flags;
3229         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3230         __ffs_event_add(ffs, type);
3231         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3232 }
3233
3234 /* Bind/unbind USB function hooks *******************************************/
3235
3236 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
3237 {
3238         int i;
3239
3240         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
3241                 if (ffs->eps_addrmap[i] == endpoint_address)
3242                         return i;
3243         return -ENOENT;
3244 }
3245
3246 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
3247                                     struct usb_descriptor_header *desc,
3248                                     void *priv)
3249 {
3250         struct usb_endpoint_descriptor *ds = (void *)desc;
3251         struct ffs_function *func = priv;
3252         struct ffs_ep *ffs_ep;
3253         unsigned ep_desc_id;
3254         int idx;
3255         static const char *speed_names[] = { "full", "high", "super" };
3256
3257         if (type != FFS_DESCRIPTOR)
3258                 return 0;
3259
3260         /*
3261          * If ss_descriptors is not NULL, we are reading super speed
3262          * descriptors; if hs_descriptors is not NULL, we are reading high
3263          * speed descriptors; otherwise, we are reading full speed
3264          * descriptors.
3265          */
3266         if (func->function.ss_descriptors) {
3267                 ep_desc_id = 2;
3268                 func->function.ss_descriptors[(long)valuep] = desc;
3269         } else if (func->function.hs_descriptors) {
3270                 ep_desc_id = 1;
3271                 func->function.hs_descriptors[(long)valuep] = desc;
3272         } else {
3273                 ep_desc_id = 0;
3274                 func->function.fs_descriptors[(long)valuep]    = desc;
3275         }
3276
3277         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
3278                 return 0;
3279
3280         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
3281         if (idx < 0)
3282                 return idx;
3283
3284         ffs_ep = func->eps + idx;
3285
3286         if (ffs_ep->descs[ep_desc_id]) {
3287                 pr_err("two %sspeed descriptors for EP %d\n",
3288                           speed_names[ep_desc_id],
3289                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
3290                 return -EINVAL;
3291         }
3292         ffs_ep->descs[ep_desc_id] = ds;
3293
3294         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
3295         if (ffs_ep->ep) {
3296                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
3297                 if (!ds->wMaxPacketSize)
3298                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
3299         } else {
3300                 struct usb_request *req;
3301                 struct usb_ep *ep;
3302                 u8 bEndpointAddress;
3303                 u16 wMaxPacketSize;
3304
3305                 /*
3306                  * We back up bEndpointAddress because autoconfig overwrites
3307                  * it with physical endpoint address.
3308                  */
3309                 bEndpointAddress = ds->bEndpointAddress;
3310                 /*
3311                  * We back up wMaxPacketSize because autoconfig treats
3312                  * endpoint descriptors as if they were full speed.
3313                  */
3314                 wMaxPacketSize = ds->wMaxPacketSize;
3315                 pr_vdebug("autoconfig\n");
3316                 ep = usb_ep_autoconfig(func->gadget, ds);
3317                 if (!ep)
3318                         return -ENOTSUPP;
3319                 ep->driver_data = func->eps + idx;
3320
3321                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
3322                 if (!req)
3323                         return -ENOMEM;
3324
3325                 ffs_ep->ep  = ep;
3326                 ffs_ep->req = req;
3327                 func->eps_revmap[ds->bEndpointAddress &
3328                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
3329                 /*
3330                  * If we use virtual address mapping, we restore
3331                  * original bEndpointAddress value.
3332                  */
3333                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3334                         ds->bEndpointAddress = bEndpointAddress;
3335                 /*
3336                  * Restore wMaxPacketSize which was potentially
3337                  * overwritten by autoconfig.
3338                  */
3339                 ds->wMaxPacketSize = wMaxPacketSize;
3340         }
3341         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
3342
3343         return 0;
3344 }
3345
3346 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
3347                                    struct usb_descriptor_header *desc,
3348                                    void *priv)
3349 {
3350         struct ffs_function *func = priv;
3351         unsigned idx;
3352         u8 newValue;
3353
3354         switch (type) {
3355         default:
3356         case FFS_DESCRIPTOR:
3357                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
3358                 return 0;
3359
3360         case FFS_INTERFACE:
3361                 idx = *valuep;
3362                 if (func->interfaces_nums[idx] < 0) {
3363                         int id = usb_interface_id(func->conf, &func->function);
3364                         if (id < 0)
3365                                 return id;
3366                         func->interfaces_nums[idx] = id;
3367                 }
3368                 newValue = func->interfaces_nums[idx];
3369                 break;
3370
3371         case FFS_STRING:
3372                 /* String' IDs are allocated when fsf_data is bound to cdev */
3373                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
3374                 break;
3375
3376         case FFS_ENDPOINT:
3377                 /*
3378                  * USB_DT_ENDPOINT are handled in
3379                  * __ffs_func_bind_do_descs().
3380                  */
3381                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
3382                         return 0;
3383
3384                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
3385                 if (!func->eps[idx].ep)
3386                         return -EINVAL;
3387
3388                 {
3389                         struct usb_endpoint_descriptor **descs;
3390                         descs = func->eps[idx].descs;
3391                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
3392                 }
3393                 break;
3394         }
3395
3396         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
3397         *valuep = newValue;
3398         return 0;
3399 }
3400
3401 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
3402                                       struct usb_os_desc_header *h, void *data,
3403                                       unsigned len, void *priv)
3404 {
3405         struct ffs_function *func = priv;
3406         u8 length = 0;
3407
3408         switch (type) {
3409         case FFS_OS_DESC_EXT_COMPAT: {
3410                 struct usb_ext_compat_desc *desc = data;
3411                 struct usb_os_desc_table *t;
3412
3413                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3414                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3415                 memcpy(t->os_desc->ext_compat_id, &desc->IDs,
3416                        sizeof_field(struct usb_ext_compat_desc, IDs));
3417                 length = sizeof(*desc);
3418         }
3419                 break;
3420         case FFS_OS_DESC_EXT_PROP: {
3421                 struct usb_ext_prop_desc *desc = data;
3422                 struct usb_os_desc_table *t;
3423                 struct usb_os_desc_ext_prop *ext_prop;
3424                 char *ext_prop_name;
3425                 char *ext_prop_data;
3426
3427                 t = &func->function.os_desc_table[h->interface];
3428                 t->if_id = func->interfaces_nums[h->interface];
3429
3430                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3431                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3432
3433                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3434                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3435                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3436                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3437                 length = ext_prop->name_len + ext_prop->data_len + 14;
3438
3439                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3440                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3441                         ext_prop->name_len;
3442
3443                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3444                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3445                         ext_prop->data_len;
3446                 memcpy(ext_prop_data,
3447                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3448                        ext_prop->data_len);
3449                 /* unicode data reported to the host as "WCHAR"s */
3450                 switch (ext_prop->type) {
3451                 case USB_EXT_PROP_UNICODE:
3452                 case USB_EXT_PROP_UNICODE_ENV:
3453                 case USB_EXT_PROP_UNICODE_LINK:
3454                 case USB_EXT_PROP_UNICODE_MULTI:
3455                         ext_prop->data_len *= 2;
3456                         break;
3457                 }
3458                 ext_prop->data = ext_prop_data;
3459
3460                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3461                        ext_prop->name_len);
3462                 /* property name reported to the host as "WCHAR"s */
3463                 ext_prop->name_len *= 2;
3464                 ext_prop->name = ext_prop_name;
3465
3466                 t->os_desc->ext_prop_len +=
3467                         ext_prop->name_len + ext_prop->data_len + 14;
3468                 ++t->os_desc->ext_prop_count;
3469                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3470         }
3471                 break;
3472         default:
3473                 pr_vdebug("unknown descriptor: %d\n", type);
3474         }
3475
3476         return length;
3477 }
3478
3479 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3480                                                 struct usb_configuration *c)
3481 {
3482         struct ffs_function *func = ffs_func_from_usb(f);
3483         struct f_fs_opts *ffs_opts =
3484                 container_of(f->fi, struct f_fs_opts, func_inst);
3485         struct ffs_data *ffs_data;
3486         int ret;
3487
3488         /*
3489          * Legacy gadget triggers binding in functionfs_ready_callback,
3490          * which already uses locking; taking the same lock here would
3491          * cause a deadlock.
3492          *
3493          * Configfs-enabled gadgets however do need ffs_dev_lock.
3494          */
3495         if (!ffs_opts->no_configfs)
3496                 ffs_dev_lock();
3497         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3498         ffs_data = ffs_opts->dev->ffs_data;
3499         if (!ffs_opts->no_configfs)
3500                 ffs_dev_unlock();
3501         if (ret)
3502                 return ERR_PTR(ret);
3503
3504         func->ffs = ffs_data;
3505         func->conf = c;
3506         func->gadget = c->cdev->gadget;
3507
3508         /*
3509          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3510          * configurations are bound in sequence with list_for_each_entry,
3511          * in each configuration its functions are bound in sequence
3512          * with list_for_each_entry, so we assume no race condition
3513          * with regard to ffs_opts->bound access
3514          */
3515         if (!ffs_opts->refcnt) {
3516                 ret = functionfs_bind(func->ffs, c->cdev);
3517                 if (ret)
3518                         return ERR_PTR(ret);
3519         }
3520         ffs_opts->refcnt++;
3521         func->function.strings = func->ffs->stringtabs;
3522
3523         return ffs_opts;
3524 }
3525
3526 static int _ffs_func_bind(struct usb_configuration *c,
3527                           struct usb_function *f)
3528 {
3529         struct ffs_function *func = ffs_func_from_usb(f);
3530         struct ffs_data *ffs = func->ffs;
3531
3532         const int full = !!func->ffs->fs_descs_count;
3533         const int high = !!func->ffs->hs_descs_count;
3534         const int super = !!func->ffs->ss_descs_count;
3535
3536         int fs_len, hs_len, ss_len, ret, i;
3537         struct ffs_ep *eps_ptr;
3538
3539         /* Make it a single chunk, less management later on */
3540         vla_group(d);
3541         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3542         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3543                 full ? ffs->fs_descs_count + 1 : 0);
3544         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3545                 high ? ffs->hs_descs_count + 1 : 0);
3546         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3547                 super ? ffs->ss_descs_count + 1 : 0);
3548         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3549         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3550                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3551         vla_item_with_sz(d, char[16], ext_compat,
3552                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3553         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3554                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3555         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3556                          ffs->ms_os_descs_ext_prop_count);
3557         vla_item_with_sz(d, char, ext_prop_name,
3558                          ffs->ms_os_descs_ext_prop_name_len);
3559         vla_item_with_sz(d, char, ext_prop_data,
3560                          ffs->ms_os_descs_ext_prop_data_len);
3561         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3562         char *vlabuf;
3563
3564         /* Has descriptors only for speeds gadget does not support */
3565         if (!(full | high | super))
3566                 return -ENOTSUPP;
3567
3568         /* Allocate a single chunk, less management later on */
3569         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3570         if (!vlabuf)
3571                 return -ENOMEM;
3572
3573         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3574         ffs->ms_os_descs_ext_prop_name_avail =
3575                 vla_ptr(vlabuf, d, ext_prop_name);
3576         ffs->ms_os_descs_ext_prop_data_avail =
3577                 vla_ptr(vlabuf, d, ext_prop_data);
3578
3579         /* Copy descriptors  */
3580         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3581                ffs->raw_descs_length);
3582
3583         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3584         eps_ptr = vla_ptr(vlabuf, d, eps);
3585         for (i = 0; i < ffs->eps_count; i++)
3586                 eps_ptr[i].num = -1;
3587
3588         /* Save pointers
3589          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3590         */
3591         func->eps             = vla_ptr(vlabuf, d, eps);
3592         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3593
3594         /*
3595          * Go through all the endpoint descriptors and allocate
3596          * endpoints first, so that later we can rewrite the endpoint
3597          * numbers without worrying that it may be described later on.
3598          */
3599         if (full) {
3600                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3601                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3602                                       vla_ptr(vlabuf, d, raw_descs),
3603                                       d_raw_descs__sz,
3604                                       __ffs_func_bind_do_descs, func);
3605                 if (fs_len < 0) {
3606                         ret = fs_len;
3607                         goto error;
3608                 }
3609         } else {
3610                 fs_len = 0;
3611         }
3612
3613         if (high) {
3614                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3615                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3616                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3617                                       d_raw_descs__sz - fs_len,
3618                                       __ffs_func_bind_do_descs, func);
3619                 if (hs_len < 0) {
3620                         ret = hs_len;
3621                         goto error;
3622                 }
3623         } else {
3624                 hs_len = 0;
3625         }
3626
3627         if (super) {
3628                 func->function.ss_descriptors = func->function.ssp_descriptors =
3629                         vla_ptr(vlabuf, d, ss_descs);
3630                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3631                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3632                                 d_raw_descs__sz - fs_len - hs_len,
3633                                 __ffs_func_bind_do_descs, func);
3634                 if (ss_len < 0) {
3635                         ret = ss_len;
3636                         goto error;
3637                 }
3638         } else {
3639                 ss_len = 0;
3640         }
3641
3642         /*
3643          * Now handle interface numbers allocation and interface and
3644          * endpoint numbers rewriting.  We can do that in one go
3645          * now.
3646          */
3647         ret = ffs_do_descs(ffs->fs_descs_count +
3648                            (high ? ffs->hs_descs_count : 0) +
3649                            (super ? ffs->ss_descs_count : 0),
3650                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3651                            __ffs_func_bind_do_nums, func);
3652         if (ret < 0)
3653                 goto error;
3654
3655         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3656         if (c->cdev->use_os_string) {
3657                 for (i = 0; i < ffs->interfaces_count; ++i) {
3658                         struct usb_os_desc *desc;
3659
3660                         desc = func->function.os_desc_table[i].os_desc =
3661                                 vla_ptr(vlabuf, d, os_desc) +
3662                                 i * sizeof(struct usb_os_desc);
3663                         desc->ext_compat_id =
3664                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3665                         INIT_LIST_HEAD(&desc->ext_prop);
3666                 }
3667                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3668                                       vla_ptr(vlabuf, d, raw_descs) +
3669                                       fs_len + hs_len + ss_len,
3670                                       d_raw_descs__sz - fs_len - hs_len -
3671                                       ss_len,
3672                                       __ffs_func_bind_do_os_desc, func);
3673                 if (ret < 0)
3674                         goto error;
3675         }
3676         func->function.os_desc_n =
3677                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3678
3679         /* And we're done */
3680         ffs_event_add(ffs, FUNCTIONFS_BIND);
3681         return 0;
3682
3683 error:
3684         /* XXX Do we need to release all claimed endpoints here? */
3685         return ret;
3686 }
3687
3688 static int ffs_func_bind(struct usb_configuration *c,
3689                          struct usb_function *f)
3690 {
3691         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3692         struct ffs_function *func = ffs_func_from_usb(f);
3693         int ret;
3694
3695         if (IS_ERR(ffs_opts))
3696                 return PTR_ERR(ffs_opts);
3697
3698         ret = _ffs_func_bind(c, f);
3699         if (ret && !--ffs_opts->refcnt)
3700                 functionfs_unbind(func->ffs);
3701
3702         return ret;
3703 }
3704
3705
3706 /* Other USB function hooks *************************************************/
3707
3708 static void ffs_reset_work(struct work_struct *work)
3709 {
3710         struct ffs_data *ffs = container_of(work,
3711                 struct ffs_data, reset_work);
3712         ffs_data_reset(ffs);
3713 }
3714
3715 static int ffs_func_set_alt(struct usb_function *f,
3716                             unsigned interface, unsigned alt)
3717 {
3718         struct ffs_function *func = ffs_func_from_usb(f);
3719         struct ffs_data *ffs = func->ffs;
3720         int ret = 0, intf;
3721
3722         if (alt != (unsigned)-1) {
3723                 intf = ffs_func_revmap_intf(func, interface);
3724                 if (intf < 0)
3725                         return intf;
3726         }
3727
3728         if (ffs->func)
3729                 ffs_func_eps_disable(ffs->func);
3730
3731         if (ffs->state == FFS_DEACTIVATED) {
3732                 ffs->state = FFS_CLOSING;
3733                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3734                 schedule_work(&ffs->reset_work);
3735                 return -ENODEV;
3736         }
3737
3738         if (ffs->state != FFS_ACTIVE)
3739                 return -ENODEV;
3740
3741         if (alt == (unsigned)-1) {
3742                 ffs->func = NULL;
3743                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3744                 return 0;
3745         }
3746
3747         ffs->func = func;
3748         ret = ffs_func_eps_enable(func);
3749         if (ret >= 0)
3750                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3751         return ret;
3752 }
3753
3754 static void ffs_func_disable(struct usb_function *f)
3755 {
3756         ffs_func_set_alt(f, 0, (unsigned)-1);
3757 }
3758
3759 static int ffs_func_setup(struct usb_function *f,
3760                           const struct usb_ctrlrequest *creq)
3761 {
3762         struct ffs_function *func = ffs_func_from_usb(f);
3763         struct ffs_data *ffs = func->ffs;
3764         unsigned long flags;
3765         int ret;
3766
3767         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3768         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3769         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3770         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3771         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3772
3773         /*
3774          * Most requests directed to interface go through here
3775          * (notable exceptions are set/get interface) so we need to
3776          * handle them.  All other either handled by composite or
3777          * passed to usb_configuration->setup() (if one is set).  No
3778          * matter, we will handle requests directed to endpoint here
3779          * as well (as it's straightforward).  Other request recipient
3780          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3781          * is being used.
3782          */
3783         if (ffs->state != FFS_ACTIVE)
3784                 return -ENODEV;
3785
3786         switch (creq->bRequestType & USB_RECIP_MASK) {
3787         case USB_RECIP_INTERFACE:
3788                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3789                 if (ret < 0)
3790                         return ret;
3791                 break;
3792
3793         case USB_RECIP_ENDPOINT:
3794                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3795                 if (ret < 0)
3796                         return ret;
3797                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3798                         ret = func->ffs->eps_addrmap[ret];
3799                 break;
3800
3801         default:
3802                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3803                         ret = le16_to_cpu(creq->wIndex);
3804                 else
3805                         return -EOPNOTSUPP;
3806         }
3807
3808         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3809         ffs->ev.setup = *creq;
3810         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3811         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3812         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3813
3814         return ffs->ev.setup.wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3815 }
3816
3817 static bool ffs_func_req_match(struct usb_function *f,
3818                                const struct usb_ctrlrequest *creq,
3819                                bool config0)
3820 {
3821         struct ffs_function *func = ffs_func_from_usb(f);
3822
3823         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3824                 return false;
3825
3826         switch (creq->bRequestType & USB_RECIP_MASK) {
3827         case USB_RECIP_INTERFACE:
3828                 return (ffs_func_revmap_intf(func,
3829                                              le16_to_cpu(creq->wIndex)) >= 0);
3830         case USB_RECIP_ENDPOINT:
3831                 return (ffs_func_revmap_ep(func,
3832                                            le16_to_cpu(creq->wIndex)) >= 0);
3833         default:
3834                 return (bool) (func->ffs->user_flags &
3835                                FUNCTIONFS_ALL_CTRL_RECIP);
3836         }
3837 }
3838
3839 static void ffs_func_suspend(struct usb_function *f)
3840 {
3841         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3842 }
3843
3844 static void ffs_func_resume(struct usb_function *f)
3845 {
3846         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3847 }
3848
3849
3850 /* Endpoint and interface numbers reverse mapping ***************************/
3851
3852 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3853 {
3854         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3855         return num ? num : -EDOM;
3856 }
3857
3858 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3859 {
3860         short *nums = func->interfaces_nums;
3861         unsigned count = func->ffs->interfaces_count;
3862
3863         for (; count; --count, ++nums) {
3864                 if (*nums >= 0 && *nums == intf)
3865                         return nums - func->interfaces_nums;
3866         }
3867
3868         return -EDOM;
3869 }
3870
3871
3872 /* Devices management *******************************************************/
3873
3874 static LIST_HEAD(ffs_devices);
3875
3876 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3877 {
3878         struct ffs_dev *dev;
3879
3880         if (!name)
3881                 return NULL;
3882
3883         list_for_each_entry(dev, &ffs_devices, entry) {
3884                 if (strcmp(dev->name, name) == 0)
3885                         return dev;
3886         }
3887
3888         return NULL;
3889 }
3890
3891 /*
3892  * ffs_lock must be taken by the caller of this function
3893  */
3894 static struct ffs_dev *_ffs_get_single_dev(void)
3895 {
3896         struct ffs_dev *dev;
3897
3898         if (list_is_singular(&ffs_devices)) {
3899                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3900                 if (dev->single)
3901                         return dev;
3902         }
3903
3904         return NULL;
3905 }
3906
3907 /*
3908  * ffs_lock must be taken by the caller of this function
3909  */
3910 static struct ffs_dev *_ffs_find_dev(const char *name)
3911 {
3912         struct ffs_dev *dev;
3913
3914         dev = _ffs_get_single_dev();
3915         if (dev)
3916                 return dev;
3917
3918         return _ffs_do_find_dev(name);
3919 }
3920
3921 /* Configfs support *********************************************************/
3922
3923 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3924 {
3925         return container_of(to_config_group(item), struct f_fs_opts,
3926                             func_inst.group);
3927 }
3928
3929 static ssize_t f_fs_opts_ready_show(struct config_item *item, char *page)
3930 {
3931         struct f_fs_opts *opts = to_ffs_opts(item);
3932         int ready;
3933
3934         ffs_dev_lock();
3935         ready = opts->dev->desc_ready;
3936         ffs_dev_unlock();
3937
3938         return sprintf(page, "%d\n", ready);
3939 }
3940
3941 CONFIGFS_ATTR_RO(f_fs_opts_, ready);
3942
3943 static struct configfs_attribute *ffs_attrs[] = {
3944         &f_fs_opts_attr_ready,
3945         NULL,
3946 };
3947
3948 static void ffs_attr_release(struct config_item *item)
3949 {
3950         struct f_fs_opts *opts = to_ffs_opts(item);
3951
3952         usb_put_function_instance(&opts->func_inst);
3953 }
3954
3955 static struct configfs_item_operations ffs_item_ops = {
3956         .release        = ffs_attr_release,
3957 };
3958
3959 static const struct config_item_type ffs_func_type = {
3960         .ct_item_ops    = &ffs_item_ops,
3961         .ct_attrs       = ffs_attrs,
3962         .ct_owner       = THIS_MODULE,
3963 };
3964
3965
3966 /* Function registration interface ******************************************/
3967
3968 static void ffs_free_inst(struct usb_function_instance *f)
3969 {
3970         struct f_fs_opts *opts;
3971
3972         opts = to_f_fs_opts(f);
3973         ffs_release_dev(opts->dev);
3974         ffs_dev_lock();
3975         _ffs_free_dev(opts->dev);
3976         ffs_dev_unlock();
3977         kfree(opts);
3978 }
3979
3980 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3981 {
3982         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3983                 return -ENAMETOOLONG;
3984         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3985 }
3986
3987 static struct usb_function_instance *ffs_alloc_inst(void)
3988 {
3989         struct f_fs_opts *opts;
3990         struct ffs_dev *dev;
3991
3992         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3993         if (!opts)
3994                 return ERR_PTR(-ENOMEM);
3995
3996         opts->func_inst.set_inst_name = ffs_set_inst_name;
3997         opts->func_inst.free_func_inst = ffs_free_inst;
3998         ffs_dev_lock();
3999         dev = _ffs_alloc_dev();
4000         ffs_dev_unlock();
4001         if (IS_ERR(dev)) {
4002                 kfree(opts);
4003                 return ERR_CAST(dev);
4004         }
4005         opts->dev = dev;
4006         dev->opts = opts;
4007
4008         config_group_init_type_name(&opts->func_inst.group, "",
4009                                     &ffs_func_type);
4010         return &opts->func_inst;
4011 }
4012
4013 static void ffs_free(struct usb_function *f)
4014 {
4015         kfree(ffs_func_from_usb(f));
4016 }
4017
4018 static void ffs_func_unbind(struct usb_configuration *c,
4019                             struct usb_function *f)
4020 {
4021         struct ffs_function *func = ffs_func_from_usb(f);
4022         struct ffs_data *ffs = func->ffs;
4023         struct f_fs_opts *opts =
4024                 container_of(f->fi, struct f_fs_opts, func_inst);
4025         struct ffs_ep *ep = func->eps;
4026         unsigned count = ffs->eps_count;
4027         unsigned long flags;
4028
4029         if (ffs->func == func) {
4030                 ffs_func_eps_disable(func);
4031                 ffs->func = NULL;
4032         }
4033
4034         /* Drain any pending AIO completions */
4035         drain_workqueue(ffs->io_completion_wq);
4036
4037         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
4038         if (!--opts->refcnt)
4039                 functionfs_unbind(ffs);
4040
4041         /* cleanup after autoconfig */
4042         spin_lock_irqsave(&func->ffs->eps_lock, flags);
4043         while (count--) {
4044                 if (ep->ep && ep->req)
4045                         usb_ep_free_request(ep->ep, ep->req);
4046                 ep->req = NULL;
4047                 ++ep;
4048         }
4049         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
4050         kfree(func->eps);
4051         func->eps = NULL;
4052         /*
4053          * eps, descriptors and interfaces_nums are allocated in the
4054          * same chunk so only one free is required.
4055          */
4056         func->function.fs_descriptors = NULL;
4057         func->function.hs_descriptors = NULL;
4058         func->function.ss_descriptors = NULL;
4059         func->function.ssp_descriptors = NULL;
4060         func->interfaces_nums = NULL;
4061
4062 }
4063
4064 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
4065 {
4066         struct ffs_function *func;
4067
4068         func = kzalloc(sizeof(*func), GFP_KERNEL);
4069         if (!func)
4070                 return ERR_PTR(-ENOMEM);
4071
4072         func->function.name    = "Function FS Gadget";
4073
4074         func->function.bind    = ffs_func_bind;
4075         func->function.unbind  = ffs_func_unbind;
4076         func->function.set_alt = ffs_func_set_alt;
4077         func->function.disable = ffs_func_disable;
4078         func->function.setup   = ffs_func_setup;
4079         func->function.req_match = ffs_func_req_match;
4080         func->function.suspend = ffs_func_suspend;
4081         func->function.resume  = ffs_func_resume;
4082         func->function.free_func = ffs_free;
4083
4084         return &func->function;
4085 }
4086
4087 /*
4088  * ffs_lock must be taken by the caller of this function
4089  */
4090 static struct ffs_dev *_ffs_alloc_dev(void)
4091 {
4092         struct ffs_dev *dev;
4093         int ret;
4094
4095         if (_ffs_get_single_dev())
4096                         return ERR_PTR(-EBUSY);
4097
4098         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4099         if (!dev)
4100                 return ERR_PTR(-ENOMEM);
4101
4102         if (list_empty(&ffs_devices)) {
4103                 ret = functionfs_init();
4104                 if (ret) {
4105                         kfree(dev);
4106                         return ERR_PTR(ret);
4107                 }
4108         }
4109
4110         list_add(&dev->entry, &ffs_devices);
4111
4112         return dev;
4113 }
4114
4115 int ffs_name_dev(struct ffs_dev *dev, const char *name)
4116 {
4117         struct ffs_dev *existing;
4118         int ret = 0;
4119
4120         ffs_dev_lock();
4121
4122         existing = _ffs_do_find_dev(name);
4123         if (!existing)
4124                 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
4125         else if (existing != dev)
4126                 ret = -EBUSY;
4127
4128         ffs_dev_unlock();
4129
4130         return ret;
4131 }
4132 EXPORT_SYMBOL_GPL(ffs_name_dev);
4133
4134 int ffs_single_dev(struct ffs_dev *dev)
4135 {
4136         int ret;
4137
4138         ret = 0;
4139         ffs_dev_lock();
4140
4141         if (!list_is_singular(&ffs_devices))
4142                 ret = -EBUSY;
4143         else
4144                 dev->single = true;
4145
4146         ffs_dev_unlock();
4147         return ret;
4148 }
4149 EXPORT_SYMBOL_GPL(ffs_single_dev);
4150
4151 /*
4152  * ffs_lock must be taken by the caller of this function
4153  */
4154 static void _ffs_free_dev(struct ffs_dev *dev)
4155 {
4156         list_del(&dev->entry);
4157
4158         kfree(dev);
4159         if (list_empty(&ffs_devices))
4160                 functionfs_cleanup();
4161 }
4162
4163 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
4164 {
4165         int ret = 0;
4166         struct ffs_dev *ffs_dev;
4167
4168         ffs_dev_lock();
4169
4170         ffs_dev = _ffs_find_dev(dev_name);
4171         if (!ffs_dev) {
4172                 ret = -ENOENT;
4173         } else if (ffs_dev->mounted) {
4174                 ret = -EBUSY;
4175         } else if (ffs_dev->ffs_acquire_dev_callback &&
4176                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
4177                 ret = -ENOENT;
4178         } else {
4179                 ffs_dev->mounted = true;
4180                 ffs_dev->ffs_data = ffs_data;
4181                 ffs_data->private_data = ffs_dev;
4182         }
4183
4184         ffs_dev_unlock();
4185         return ret;
4186 }
4187
4188 static void ffs_release_dev(struct ffs_dev *ffs_dev)
4189 {
4190         ffs_dev_lock();
4191
4192         if (ffs_dev && ffs_dev->mounted) {
4193                 ffs_dev->mounted = false;
4194                 if (ffs_dev->ffs_data) {
4195                         ffs_dev->ffs_data->private_data = NULL;
4196                         ffs_dev->ffs_data = NULL;
4197                 }
4198
4199                 if (ffs_dev->ffs_release_dev_callback)
4200                         ffs_dev->ffs_release_dev_callback(ffs_dev);
4201         }
4202
4203         ffs_dev_unlock();
4204 }
4205
4206 static int ffs_ready(struct ffs_data *ffs)
4207 {
4208         struct ffs_dev *ffs_obj;
4209         int ret = 0;
4210
4211         ffs_dev_lock();
4212
4213         ffs_obj = ffs->private_data;
4214         if (!ffs_obj) {
4215                 ret = -EINVAL;
4216                 goto done;
4217         }
4218         if (WARN_ON(ffs_obj->desc_ready)) {
4219                 ret = -EBUSY;
4220                 goto done;
4221         }
4222
4223         ffs_obj->desc_ready = true;
4224
4225         if (ffs_obj->ffs_ready_callback) {
4226                 ret = ffs_obj->ffs_ready_callback(ffs);
4227                 if (ret)
4228                         goto done;
4229         }
4230
4231         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
4232 done:
4233         ffs_dev_unlock();
4234         return ret;
4235 }
4236
4237 static void ffs_closed(struct ffs_data *ffs)
4238 {
4239         struct ffs_dev *ffs_obj;
4240         struct f_fs_opts *opts;
4241         struct config_item *ci;
4242
4243         ffs_dev_lock();
4244
4245         ffs_obj = ffs->private_data;
4246         if (!ffs_obj)
4247                 goto done;
4248
4249         ffs_obj->desc_ready = false;
4250
4251         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
4252             ffs_obj->ffs_closed_callback)
4253                 ffs_obj->ffs_closed_callback(ffs);
4254
4255         if (ffs_obj->opts)
4256                 opts = ffs_obj->opts;
4257         else
4258                 goto done;
4259
4260         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
4261             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
4262                 goto done;
4263
4264         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
4265         ffs_dev_unlock();
4266
4267         if (test_bit(FFS_FL_BOUND, &ffs->flags))
4268                 unregister_gadget_item(ci);
4269         return;
4270 done:
4271         ffs_dev_unlock();
4272 }
4273
4274 /* Misc helper functions ****************************************************/
4275
4276 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
4277 {
4278         return nonblock
4279                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
4280                 : mutex_lock_interruptible(mutex);
4281 }
4282
4283 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
4284 {
4285         char *data;
4286
4287         if (!len)
4288                 return NULL;
4289
4290         data = memdup_user(buf, len);
4291         if (IS_ERR(data))
4292                 return data;
4293
4294         pr_vdebug("Buffer from user space:\n");
4295         ffs_dump_mem("", data, len);
4296
4297         return data;
4298 }
4299
4300 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
4301 MODULE_LICENSE("GPL");
4302 MODULE_AUTHOR("Michal Nazarewicz");