fs/ksmbd/vfs_cache.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
   4  * Copyright (C) 2019 Samsung Electronics Co., Ltd.
   5  */
   6
   7 #include <linux/fs.h>
   8 #include <linux/filelock.h>
   9 #include <linux/slab.h>
  10 #include <linux/vmalloc.h>
  11
  12 #include "glob.h"
  13 #include "vfs_cache.h"
  14 #include "oplock.h"
  15 #include "vfs.h"
  16 #include "connection.h"
  17 #include "mgmt/tree_connect.h"
  18 #include "mgmt/user_session.h"
  19 #include "smb_common.h"
  20
  21 #define S_DEL_PENDING                   1
  22 #define S_DEL_ON_CLS                    2
  23 #define S_DEL_ON_CLS_STREAM             8
  24
  25 static unsigned int inode_hash_mask __read_mostly;
  26 static unsigned int inode_hash_shift __read_mostly;
  27 static struct hlist_head *inode_hashtable __read_mostly;
  28 static DEFINE_RWLOCK(inode_hash_lock);
  29
  30 static struct ksmbd_file_table global_ft;
  31 static atomic_long_t fd_limit;
  32 static struct kmem_cache *filp_cache;
  33
  34 void ksmbd_set_fd_limit(unsigned long limit)
  35 {
  36         limit = min(limit, get_max_files());
  37         atomic_long_set(&fd_limit, limit);
  38 }
  39
  40 static bool fd_limit_depleted(void)
  41 {
  42         long v = atomic_long_dec_return(&fd_limit);
  43
  44         if (v >= 0)
  45                 return false;
  46         atomic_long_inc(&fd_limit);
  47         return true;
  48 }
  49
  50 static void fd_limit_close(void)
  51 {
  52         atomic_long_inc(&fd_limit);
  53 }
  54
  55 /*
  56  * INODE hash
  57  */
  58
  59 static unsigned long inode_hash(struct super_block *sb, unsigned long hashval)
  60 {
  61         unsigned long tmp;
  62
  63         tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
  64                 L1_CACHE_BYTES;
  65         tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> inode_hash_shift);
  66         return tmp & inode_hash_mask;
  67 }
  68
  69 static struct ksmbd_inode *__ksmbd_inode_lookup(struct inode *inode)
  70 {
  71         struct hlist_head *head = inode_hashtable +
  72                 inode_hash(inode->i_sb, inode->i_ino);
  73         struct ksmbd_inode *ci = NULL, *ret_ci = NULL;
  74
  75         hlist_for_each_entry(ci, head, m_hash) {
  76                 if (ci->m_inode == inode) {
  77                         if (atomic_inc_not_zero(&ci->m_count))
  78                                 ret_ci = ci;
  79                         break;
  80                 }
  81         }
  82         return ret_ci;
  83 }
  84
  85 static struct ksmbd_inode *ksmbd_inode_lookup(struct ksmbd_file *fp)
  86 {
  87         return __ksmbd_inode_lookup(file_inode(fp->filp));
  88 }
  89
  90 static struct ksmbd_inode *ksmbd_inode_lookup_by_vfsinode(struct inode *inode)
  91 {
  92         struct ksmbd_inode *ci;
  93
  94         read_lock(&inode_hash_lock);
  95         ci = __ksmbd_inode_lookup(inode);
  96         read_unlock(&inode_hash_lock);
  97         return ci;
  98 }
  99
 100 int ksmbd_query_inode_status(struct inode *inode)
 101 {
 102         struct ksmbd_inode *ci;
 103         int ret = KSMBD_INODE_STATUS_UNKNOWN;
 104
 105         read_lock(&inode_hash_lock);
 106         ci = __ksmbd_inode_lookup(inode);
 107         if (ci) {
 108                 ret = KSMBD_INODE_STATUS_OK;
 109                 if (ci->m_flags & S_DEL_PENDING)
 110                         ret = KSMBD_INODE_STATUS_PENDING_DELETE;
 111                 atomic_dec(&ci->m_count);
 112         }
 113         read_unlock(&inode_hash_lock);
 114         return ret;
 115 }
 116
 117 bool ksmbd_inode_pending_delete(struct ksmbd_file *fp)
 118 {
 119         return (fp->f_ci->m_flags & S_DEL_PENDING);
 120 }
 121
 122 void ksmbd_set_inode_pending_delete(struct ksmbd_file *fp)
 123 {
 124         fp->f_ci->m_flags |= S_DEL_PENDING;
 125 }
 126
 127 void ksmbd_clear_inode_pending_delete(struct ksmbd_file *fp)
 128 {
 129         fp->f_ci->m_flags &= ~S_DEL_PENDING;
 130 }
 131
 132 void ksmbd_fd_set_delete_on_close(struct ksmbd_file *fp,
 133                                   int file_info)
 134 {
 135         if (ksmbd_stream_fd(fp)) {
 136                 fp->f_ci->m_flags |= S_DEL_ON_CLS_STREAM;
 137                 return;
 138         }
 139
 140         fp->f_ci->m_flags |= S_DEL_ON_CLS;
 141 }
 142
 143 static void ksmbd_inode_hash(struct ksmbd_inode *ci)
 144 {
 145         struct hlist_head *b = inode_hashtable +
 146                 inode_hash(ci->m_inode->i_sb, ci->m_inode->i_ino);
 147
 148         hlist_add_head(&ci->m_hash, b);
 149 }
 150
 151 static void ksmbd_inode_unhash(struct ksmbd_inode *ci)
 152 {
 153         write_lock(&inode_hash_lock);
 154         hlist_del_init(&ci->m_hash);
 155         write_unlock(&inode_hash_lock);
 156 }
 157
 158 static int ksmbd_inode_init(struct ksmbd_inode *ci, struct ksmbd_file *fp)
 159 {
 160         ci->m_inode = file_inode(fp->filp);
 161         atomic_set(&ci->m_count, 1);
 162         atomic_set(&ci->op_count, 0);
 163         atomic_set(&ci->sop_count, 0);
 164         ci->m_flags = 0;
 165         ci->m_fattr = 0;
 166         INIT_LIST_HEAD(&ci->m_fp_list);
 167         INIT_LIST_HEAD(&ci->m_op_list);
 168         rwlock_init(&ci->m_lock);
 169         return 0;
 170 }
 171
 172 static struct ksmbd_inode *ksmbd_inode_get(struct ksmbd_file *fp)
 173 {
 174         struct ksmbd_inode *ci, *tmpci;
 175         int rc;
 176
 177         read_lock(&inode_hash_lock);
 178         ci = ksmbd_inode_lookup(fp);
 179         read_unlock(&inode_hash_lock);
 180         if (ci)
 181                 return ci;
 182
 183         ci = kmalloc(sizeof(struct ksmbd_inode), GFP_KERNEL);
 184         if (!ci)
 185                 return NULL;
 186
 187         rc = ksmbd_inode_init(ci, fp);
 188         if (rc) {
 189                 pr_err("inode initialized failed\n");
 190                 kfree(ci);
 191                 return NULL;
 192         }
 193
 194         write_lock(&inode_hash_lock);
 195         tmpci = ksmbd_inode_lookup(fp);
 196         if (!tmpci) {
 197                 ksmbd_inode_hash(ci);
 198         } else {
 199                 kfree(ci);
 200                 ci = tmpci;
 201         }
 202         write_unlock(&inode_hash_lock);
 203         return ci;
 204 }
 205
 206 static void ksmbd_inode_free(struct ksmbd_inode *ci)
 207 {
 208         ksmbd_inode_unhash(ci);
 209         kfree(ci);
 210 }
 211
 212 static void ksmbd_inode_put(struct ksmbd_inode *ci)
 213 {
 214         if (atomic_dec_and_test(&ci->m_count))
 215                 ksmbd_inode_free(ci);
 216 }
 217
 218 int __init ksmbd_inode_hash_init(void)
 219 {
 220         unsigned int loop;
 221         unsigned long numentries = 16384;
 222         unsigned long bucketsize = sizeof(struct hlist_head);
 223         unsigned long size;
 224
 225         inode_hash_shift = ilog2(numentries);
 226         inode_hash_mask = (1 << inode_hash_shift) - 1;
 227
 228         size = bucketsize << inode_hash_shift;
 229
 230         /* init master fp hash table */
 231         inode_hashtable = vmalloc(size);
 232         if (!inode_hashtable)
 233                 return -ENOMEM;
 234
 235         for (loop = 0; loop < (1U << inode_hash_shift); loop++)
 236                 INIT_HLIST_HEAD(&inode_hashtable[loop]);
 237         return 0;
 238 }
 239
 240 void ksmbd_release_inode_hash(void)
 241 {
 242         vfree(inode_hashtable);
 243 }
 244
 245 static void __ksmbd_inode_close(struct ksmbd_file *fp)
 246 {
 247         struct ksmbd_inode *ci = fp->f_ci;
 248         int err;
 249         struct file *filp;
 250
 251         filp = fp->filp;
 252         if (ksmbd_stream_fd(fp) && (ci->m_flags & S_DEL_ON_CLS_STREAM)) {
 253                 ci->m_flags &= ~S_DEL_ON_CLS_STREAM;
 254                 err = ksmbd_vfs_remove_xattr(file_mnt_idmap(filp),
 255                                              filp->f_path.dentry,
 256                                              fp->stream.name);
 257                 if (err)
 258                         pr_err("remove xattr failed : %s\n",
 259                                fp->stream.name);
 260         }
 261
 262         if (atomic_dec_and_test(&ci->m_count)) {
 263                 write_lock(&ci->m_lock);
 264                 if (ci->m_flags & (S_DEL_ON_CLS | S_DEL_PENDING)) {
 265                         ci->m_flags &= ~(S_DEL_ON_CLS | S_DEL_PENDING);
 266                         write_unlock(&ci->m_lock);
 267                         ksmbd_vfs_unlink(filp);
 268                         write_lock(&ci->m_lock);
 269                 }
 270                 write_unlock(&ci->m_lock);
 271
 272                 ksmbd_inode_free(ci);
 273         }
 274 }
 275
 276 static void __ksmbd_remove_durable_fd(struct ksmbd_file *fp)
 277 {
 278         if (!has_file_id(fp->persistent_id))
 279                 return;
 280
 281         write_lock(&global_ft.lock);
 282         idr_remove(global_ft.idr, fp->persistent_id);
 283         write_unlock(&global_ft.lock);
 284 }
 285
 286 static void __ksmbd_remove_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
 287 {
 288         if (!has_file_id(fp->volatile_id))
 289                 return;
 290
 291         write_lock(&fp->f_ci->m_lock);
 292         list_del_init(&fp->node);
 293         write_unlock(&fp->f_ci->m_lock);
 294
 295         write_lock(&ft->lock);
 296         idr_remove(ft->idr, fp->volatile_id);
 297         write_unlock(&ft->lock);
 298 }
 299
 300 static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
 301 {
 302         struct file *filp;
 303         struct ksmbd_lock *smb_lock, *tmp_lock;
 304
 305         fd_limit_close();
 306         __ksmbd_remove_durable_fd(fp);
 307         __ksmbd_remove_fd(ft, fp);
 308
 309         close_id_del_oplock(fp);
 310         filp = fp->filp;
 311
 312         __ksmbd_inode_close(fp);
 313         if (!IS_ERR_OR_NULL(filp))
 314                 fput(filp);
 315
 316         /* because the reference count of fp is 0, it is guaranteed that
 317          * there are not accesses to fp->lock_list.
 318          */
 319         list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) {
 320                 spin_lock(&fp->conn->llist_lock);
 321                 list_del(&smb_lock->clist);
 322                 spin_unlock(&fp->conn->llist_lock);
 323
 324                 list_del(&smb_lock->flist);
 325                 locks_free_lock(smb_lock->fl);
 326                 kfree(smb_lock);
 327         }
 328
 329         if (ksmbd_stream_fd(fp))
 330                 kfree(fp->stream.name);
 331         kmem_cache_free(filp_cache, fp);
 332 }
 333
 334 static struct ksmbd_file *ksmbd_fp_get(struct ksmbd_file *fp)
 335 {
 336         if (!atomic_inc_not_zero(&fp->refcount))
 337                 return NULL;
 338         return fp;
 339 }
 340
 341 static struct ksmbd_file *__ksmbd_lookup_fd(struct ksmbd_file_table *ft,
 342                                             u64 id)
 343 {
 344         struct ksmbd_file *fp;
 345
 346         if (!has_file_id(id))
 347                 return NULL;
 348
 349         read_lock(&ft->lock);
 350         fp = idr_find(ft->idr, id);
 351         if (fp)
 352                 fp = ksmbd_fp_get(fp);
 353         read_unlock(&ft->lock);
 354         return fp;
 355 }
 356
 357 static void __put_fd_final(struct ksmbd_work *work, struct ksmbd_file *fp)
 358 {
 359         __ksmbd_close_fd(&work->sess->file_table, fp);
 360         atomic_dec(&work->conn->stats.open_files_count);
 361 }
 362
 363 static void set_close_state_blocked_works(struct ksmbd_file *fp)
 364 {
 365         struct ksmbd_work *cancel_work;
 366
 367         spin_lock(&fp->f_lock);
 368         list_for_each_entry(cancel_work, &fp->blocked_works,
 369                                  fp_entry) {
 370                 cancel_work->state = KSMBD_WORK_CLOSED;
 371                 cancel_work->cancel_fn(cancel_work->cancel_argv);
 372         }
 373         spin_unlock(&fp->f_lock);
 374 }
 375
 376 int ksmbd_close_fd(struct ksmbd_work *work, u64 id)
 377 {
 378         struct ksmbd_file       *fp;
 379         struct ksmbd_file_table *ft;
 380
 381         if (!has_file_id(id))
 382                 return 0;
 383
 384         ft = &work->sess->file_table;
 385         read_lock(&ft->lock);
 386         fp = idr_find(ft->idr, id);
 387         if (fp) {
 388                 set_close_state_blocked_works(fp);
 389
 390                 if (!atomic_dec_and_test(&fp->refcount))
 391                         fp = NULL;
 392         }
 393         read_unlock(&ft->lock);
 394
 395         if (!fp)
 396                 return -EINVAL;
 397
 398         __put_fd_final(work, fp);
 399         return 0;
 400 }
 401
 402 void ksmbd_fd_put(struct ksmbd_work *work, struct ksmbd_file *fp)
 403 {
 404         if (!fp)
 405                 return;
 406
 407         if (!atomic_dec_and_test(&fp->refcount))
 408                 return;
 409         __put_fd_final(work, fp);
 410 }
 411
 412 static bool __sanity_check(struct ksmbd_tree_connect *tcon, struct ksmbd_file *fp)
 413 {
 414         if (!fp)
 415                 return false;
 416         if (fp->tcon != tcon)
 417                 return false;
 418         return true;
 419 }
 420
 421 struct ksmbd_file *ksmbd_lookup_foreign_fd(struct ksmbd_work *work, u64 id)
 422 {
 423         return __ksmbd_lookup_fd(&work->sess->file_table, id);
 424 }
 425
 426 struct ksmbd_file *ksmbd_lookup_fd_fast(struct ksmbd_work *work, u64 id)
 427 {
 428         struct ksmbd_file *fp = __ksmbd_lookup_fd(&work->sess->file_table, id);
 429
 430         if (__sanity_check(work->tcon, fp))
 431                 return fp;
 432
 433         ksmbd_fd_put(work, fp);
 434         return NULL;
 435 }
 436
 437 struct ksmbd_file *ksmbd_lookup_fd_slow(struct ksmbd_work *work, u64 id,
 438                                         u64 pid)
 439 {
 440         struct ksmbd_file *fp;
 441
 442         if (!has_file_id(id)) {
 443                 id = work->compound_fid;
 444                 pid = work->compound_pfid;
 445         }
 446
 447         fp = __ksmbd_lookup_fd(&work->sess->file_table, id);
 448         if (!__sanity_check(work->tcon, fp)) {
 449                 ksmbd_fd_put(work, fp);
 450                 return NULL;
 451         }
 452         if (fp->persistent_id != pid) {
 453                 ksmbd_fd_put(work, fp);
 454                 return NULL;
 455         }
 456         return fp;
 457 }
 458
 459 struct ksmbd_file *ksmbd_lookup_durable_fd(unsigned long long id)
 460 {
 461         return __ksmbd_lookup_fd(&global_ft, id);
 462 }
 463
 464 struct ksmbd_file *ksmbd_lookup_fd_cguid(char *cguid)
 465 {
 466         struct ksmbd_file       *fp = NULL;
 467         unsigned int            id;
 468
 469         read_lock(&global_ft.lock);
 470         idr_for_each_entry(global_ft.idr, fp, id) {
 471                 if (!memcmp(fp->create_guid,
 472                             cguid,
 473                             SMB2_CREATE_GUID_SIZE)) {
 474                         fp = ksmbd_fp_get(fp);
 475                         break;
 476                 }
 477         }
 478         read_unlock(&global_ft.lock);
 479
 480         return fp;
 481 }
 482
 483 struct ksmbd_file *ksmbd_lookup_fd_inode(struct inode *inode)
 484 {
 485         struct ksmbd_file       *lfp;
 486         struct ksmbd_inode      *ci;
 487
 488         ci = ksmbd_inode_lookup_by_vfsinode(inode);
 489         if (!ci)
 490                 return NULL;
 491
 492         read_lock(&ci->m_lock);
 493         list_for_each_entry(lfp, &ci->m_fp_list, node) {
 494                 if (inode == file_inode(lfp->filp)) {
 495                         atomic_dec(&ci->m_count);
 496                         lfp = ksmbd_fp_get(lfp);
 497                         read_unlock(&ci->m_lock);
 498                         return lfp;
 499                 }
 500         }
 501         atomic_dec(&ci->m_count);
 502         read_unlock(&ci->m_lock);
 503         return NULL;
 504 }
 505
 506 #define OPEN_ID_TYPE_VOLATILE_ID        (0)
 507 #define OPEN_ID_TYPE_PERSISTENT_ID      (1)
 508
 509 static void __open_id_set(struct ksmbd_file *fp, u64 id, int type)
 510 {
 511         if (type == OPEN_ID_TYPE_VOLATILE_ID)
 512                 fp->volatile_id = id;
 513         if (type == OPEN_ID_TYPE_PERSISTENT_ID)
 514                 fp->persistent_id = id;
 515 }
 516
 517 static int __open_id(struct ksmbd_file_table *ft, struct ksmbd_file *fp,
 518                      int type)
 519 {
 520         u64                     id = 0;
 521         int                     ret;
 522
 523         if (type == OPEN_ID_TYPE_VOLATILE_ID && fd_limit_depleted()) {
 524                 __open_id_set(fp, KSMBD_NO_FID, type);
 525                 return -EMFILE;
 526         }
 527
 528         idr_preload(GFP_KERNEL);
 529         write_lock(&ft->lock);
 530         ret = idr_alloc_cyclic(ft->idr, fp, 0, INT_MAX - 1, GFP_NOWAIT);
 531         if (ret >= 0) {
 532                 id = ret;
 533                 ret = 0;
 534         } else {
 535                 id = KSMBD_NO_FID;
 536                 fd_limit_close();
 537         }
 538
 539         __open_id_set(fp, id, type);
 540         write_unlock(&ft->lock);
 541         idr_preload_end();
 542         return ret;
 543 }
 544
 545 unsigned int ksmbd_open_durable_fd(struct ksmbd_file *fp)
 546 {
 547         __open_id(&global_ft, fp, OPEN_ID_TYPE_PERSISTENT_ID);
 548         return fp->persistent_id;
 549 }
 550
 551 struct ksmbd_file *ksmbd_open_fd(struct ksmbd_work *work, struct file *filp)
 552 {
 553         struct ksmbd_file *fp;
 554         int ret;
 555
 556         fp = kmem_cache_zalloc(filp_cache, GFP_KERNEL);
 557         if (!fp) {
 558                 pr_err("Failed to allocate memory\n");
 559                 return ERR_PTR(-ENOMEM);
 560         }
 561
 562         INIT_LIST_HEAD(&fp->blocked_works);
 563         INIT_LIST_HEAD(&fp->node);
 564         INIT_LIST_HEAD(&fp->lock_list);
 565         spin_lock_init(&fp->f_lock);
 566         atomic_set(&fp->refcount, 1);
 567
 568         fp->filp                = filp;
 569         fp->conn                = work->conn;
 570         fp->tcon                = work->tcon;
 571         fp->volatile_id         = KSMBD_NO_FID;
 572         fp->persistent_id       = KSMBD_NO_FID;
 573         fp->f_ci                = ksmbd_inode_get(fp);
 574
 575         if (!fp->f_ci) {
 576                 ret = -ENOMEM;
 577                 goto err_out;
 578         }
 579
 580         ret = __open_id(&work->sess->file_table, fp, OPEN_ID_TYPE_VOLATILE_ID);
 581         if (ret) {
 582                 ksmbd_inode_put(fp->f_ci);
 583                 goto err_out;
 584         }
 585
 586         atomic_inc(&work->conn->stats.open_files_count);
 587         return fp;
 588
 589 err_out:
 590         kmem_cache_free(filp_cache, fp);
 591         return ERR_PTR(ret);
 592 }
 593
 594 static int
 595 __close_file_table_ids(struct ksmbd_file_table *ft,
 596                        struct ksmbd_tree_connect *tcon,
 597                        bool (*skip)(struct ksmbd_tree_connect *tcon,
 598                                     struct ksmbd_file *fp))
 599 {
 600         unsigned int                    id;
 601         struct ksmbd_file               *fp;
 602         int                             num = 0;
 603
 604         idr_for_each_entry(ft->idr, fp, id) {
 605                 if (skip(tcon, fp))
 606                         continue;
 607
 608                 set_close_state_blocked_works(fp);
 609
 610                 if (!atomic_dec_and_test(&fp->refcount))
 611                         continue;
 612                 __ksmbd_close_fd(ft, fp);
 613                 num++;
 614         }
 615         return num;
 616 }
 617
 618 static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon,
 619                                struct ksmbd_file *fp)
 620 {
 621         return fp->tcon != tcon;
 622 }
 623
 624 static bool session_fd_check(struct ksmbd_tree_connect *tcon,
 625                              struct ksmbd_file *fp)
 626 {
 627         return false;
 628 }
 629
 630 void ksmbd_close_tree_conn_fds(struct ksmbd_work *work)
 631 {
 632         int num = __close_file_table_ids(&work->sess->file_table,
 633                                          work->tcon,
 634                                          tree_conn_fd_check);
 635
 636         atomic_sub(num, &work->conn->stats.open_files_count);
 637 }
 638
 639 void ksmbd_close_session_fds(struct ksmbd_work *work)
 640 {
 641         int num = __close_file_table_ids(&work->sess->file_table,
 642                                          work->tcon,
 643                                          session_fd_check);
 644
 645         atomic_sub(num, &work->conn->stats.open_files_count);
 646 }
 647
 648 int ksmbd_init_global_file_table(void)
 649 {
 650         return ksmbd_init_file_table(&global_ft);
 651 }
 652
 653 void ksmbd_free_global_file_table(void)
 654 {
 655         struct ksmbd_file       *fp = NULL;
 656         unsigned int            id;
 657
 658         idr_for_each_entry(global_ft.idr, fp, id) {
 659                 __ksmbd_remove_durable_fd(fp);
 660                 kmem_cache_free(filp_cache, fp);
 661         }
 662
 663         ksmbd_destroy_file_table(&global_ft);
 664 }
 665
 666 int ksmbd_init_file_table(struct ksmbd_file_table *ft)
 667 {
 668         ft->idr = kzalloc(sizeof(struct idr), GFP_KERNEL);
 669         if (!ft->idr)
 670                 return -ENOMEM;
 671
 672         idr_init(ft->idr);
 673         rwlock_init(&ft->lock);
 674         return 0;
 675 }
 676
 677 void ksmbd_destroy_file_table(struct ksmbd_file_table *ft)
 678 {
 679         if (!ft->idr)
 680                 return;
 681
 682         __close_file_table_ids(ft, NULL, session_fd_check);
 683         idr_destroy(ft->idr);
 684         kfree(ft->idr);
 685         ft->idr = NULL;
 686 }
 687
 688 int ksmbd_init_file_cache(void)
 689 {
 690         filp_cache = kmem_cache_create("ksmbd_file_cache",
 691                                        sizeof(struct ksmbd_file), 0,
 692                                        SLAB_HWCACHE_ALIGN, NULL);
 693         if (!filp_cache)
 694                 goto out;
 695
 696         return 0;
 697
 698 out:
 699         pr_err("failed to allocate file cache\n");
 700         return -ENOMEM;
 701 }
 702
 703 void ksmbd_exit_file_cache(void)
 704 {
 705         kmem_cache_destroy(filp_cache);
 706 }