| 1 | /* |
| 2 | * blkfront.c |
| 3 | * |
| 4 | * XenLinux virtual block device driver. |
| 5 | * |
| 6 | * Copyright (c) 2003-2004, Keir Fraser & Steve Hand |
| 7 | * Modifications by Mark A. Williamson are (c) Intel Research Cambridge |
| 8 | * Copyright (c) 2004, Christian Limpach |
| 9 | * Copyright (c) 2004, Andrew Warfield |
| 10 | * Copyright (c) 2005, Christopher Clark |
| 11 | * Copyright (c) 2005, XenSource Ltd |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or |
| 14 | * modify it under the terms of the GNU General Public License version 2 |
| 15 | * as published by the Free Software Foundation; or, when distributed |
| 16 | * separately from the Linux kernel or incorporated into other |
| 17 | * software packages, subject to the following license: |
| 18 | * |
| 19 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 20 | * of this source file (the "Software"), to deal in the Software without |
| 21 | * restriction, including without limitation the rights to use, copy, modify, |
| 22 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| 23 | * and to permit persons to whom the Software is furnished to do so, subject to |
| 24 | * the following conditions: |
| 25 | * |
| 26 | * The above copyright notice and this permission notice shall be included in |
| 27 | * all copies or substantial portions of the Software. |
| 28 | * |
| 29 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 30 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 31 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 32 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 33 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 34 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| 35 | * IN THE SOFTWARE. |
| 36 | */ |
| 37 | |
| 38 | #include <linux/interrupt.h> |
| 39 | #include <linux/blkdev.h> |
| 40 | #include <linux/blk-mq.h> |
| 41 | #include <linux/hdreg.h> |
| 42 | #include <linux/cdrom.h> |
| 43 | #include <linux/module.h> |
| 44 | #include <linux/slab.h> |
| 45 | #include <linux/major.h> |
| 46 | #include <linux/mutex.h> |
| 47 | #include <linux/scatterlist.h> |
| 48 | #include <linux/bitmap.h> |
| 49 | #include <linux/list.h> |
| 50 | #include <linux/workqueue.h> |
| 51 | #include <linux/sched/mm.h> |
| 52 | |
| 53 | #include <xen/xen.h> |
| 54 | #include <xen/xenbus.h> |
| 55 | #include <xen/grant_table.h> |
| 56 | #include <xen/events.h> |
| 57 | #include <xen/page.h> |
| 58 | #include <xen/platform_pci.h> |
| 59 | |
| 60 | #include <xen/interface/grant_table.h> |
| 61 | #include <xen/interface/io/blkif.h> |
| 62 | #include <xen/interface/io/protocols.h> |
| 63 | |
| 64 | #include <asm/xen/hypervisor.h> |
| 65 | |
| 66 | /* |
| 67 | * The minimal size of segment supported by the block framework is PAGE_SIZE. |
| 68 | * When Linux is using a different page size than Xen, it may not be possible |
| 69 | * to put all the data in a single segment. |
| 70 | * This can happen when the backend doesn't support indirect descriptor and |
| 71 | * therefore the maximum amount of data that a request can carry is |
| 72 | * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB |
| 73 | * |
| 74 | * Note that we only support one extra request. So the Linux page size |
| 75 | * should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) = |
| 76 | * 88KB. |
| 77 | */ |
| 78 | #define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE) |
| 79 | |
| 80 | enum blkif_state { |
| 81 | BLKIF_STATE_DISCONNECTED, |
| 82 | BLKIF_STATE_CONNECTED, |
| 83 | BLKIF_STATE_SUSPENDED, |
| 84 | BLKIF_STATE_ERROR, |
| 85 | }; |
| 86 | |
| 87 | struct grant { |
| 88 | grant_ref_t gref; |
| 89 | struct page *page; |
| 90 | struct list_head node; |
| 91 | }; |
| 92 | |
| 93 | enum blk_req_status { |
| 94 | REQ_PROCESSING, |
| 95 | REQ_WAITING, |
| 96 | REQ_DONE, |
| 97 | REQ_ERROR, |
| 98 | REQ_EOPNOTSUPP, |
| 99 | }; |
| 100 | |
| 101 | struct blk_shadow { |
| 102 | struct blkif_request req; |
| 103 | struct request *request; |
| 104 | struct grant **grants_used; |
| 105 | struct grant **indirect_grants; |
| 106 | struct scatterlist *sg; |
| 107 | unsigned int num_sg; |
| 108 | enum blk_req_status status; |
| 109 | |
| 110 | #define NO_ASSOCIATED_ID ~0UL |
| 111 | /* |
| 112 | * Id of the sibling if we ever need 2 requests when handling a |
| 113 | * block I/O request |
| 114 | */ |
| 115 | unsigned long associated_id; |
| 116 | }; |
| 117 | |
| 118 | struct blkif_req { |
| 119 | blk_status_t error; |
| 120 | }; |
| 121 | |
| 122 | static inline struct blkif_req *blkif_req(struct request *rq) |
| 123 | { |
| 124 | return blk_mq_rq_to_pdu(rq); |
| 125 | } |
| 126 | |
| 127 | static DEFINE_MUTEX(blkfront_mutex); |
| 128 | static const struct block_device_operations xlvbd_block_fops; |
| 129 | static struct delayed_work blkfront_work; |
| 130 | static LIST_HEAD(info_list); |
| 131 | |
| 132 | /* |
| 133 | * Maximum number of segments in indirect requests, the actual value used by |
| 134 | * the frontend driver is the minimum of this value and the value provided |
| 135 | * by the backend driver. |
| 136 | */ |
| 137 | |
| 138 | static unsigned int xen_blkif_max_segments = 32; |
| 139 | module_param_named(max_indirect_segments, xen_blkif_max_segments, uint, 0444); |
| 140 | MODULE_PARM_DESC(max_indirect_segments, |
| 141 | "Maximum amount of segments in indirect requests (default is 32)"); |
| 142 | |
| 143 | static unsigned int xen_blkif_max_queues = 4; |
| 144 | module_param_named(max_queues, xen_blkif_max_queues, uint, 0444); |
| 145 | MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk"); |
| 146 | |
| 147 | /* |
| 148 | * Maximum order of pages to be used for the shared ring between front and |
| 149 | * backend, 4KB page granularity is used. |
| 150 | */ |
| 151 | static unsigned int xen_blkif_max_ring_order; |
| 152 | module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444); |
| 153 | MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); |
| 154 | |
| 155 | static bool __read_mostly xen_blkif_trusted = true; |
| 156 | module_param_named(trusted, xen_blkif_trusted, bool, 0644); |
| 157 | MODULE_PARM_DESC(trusted, "Is the backend trusted"); |
| 158 | |
| 159 | #define BLK_RING_SIZE(info) \ |
| 160 | __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) |
| 161 | |
| 162 | /* |
| 163 | * ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 |
| 164 | * characters are enough. Define to 20 to keep consistent with backend. |
| 165 | */ |
| 166 | #define RINGREF_NAME_LEN (20) |
| 167 | /* |
| 168 | * queue-%u would take 7 + 10(UINT_MAX) = 17 characters. |
| 169 | */ |
| 170 | #define QUEUE_NAME_LEN (17) |
| 171 | |
| 172 | /* |
| 173 | * Per-ring info. |
| 174 | * Every blkfront device can associate with one or more blkfront_ring_info, |
| 175 | * depending on how many hardware queues/rings to be used. |
| 176 | */ |
| 177 | struct blkfront_ring_info { |
| 178 | /* Lock to protect data in every ring buffer. */ |
| 179 | spinlock_t ring_lock; |
| 180 | struct blkif_front_ring ring; |
| 181 | unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
| 182 | unsigned int evtchn, irq; |
| 183 | struct work_struct work; |
| 184 | struct gnttab_free_callback callback; |
| 185 | struct list_head indirect_pages; |
| 186 | struct list_head grants; |
| 187 | unsigned int persistent_gnts_c; |
| 188 | unsigned long shadow_free; |
| 189 | struct blkfront_info *dev_info; |
| 190 | struct blk_shadow shadow[]; |
| 191 | }; |
| 192 | |
| 193 | /* |
| 194 | * We have one of these per vbd, whether ide, scsi or 'other'. They |
| 195 | * hang in private_data off the gendisk structure. We may end up |
| 196 | * putting all kinds of interesting stuff here :-) |
| 197 | */ |
| 198 | struct blkfront_info |
| 199 | { |
| 200 | struct mutex mutex; |
| 201 | struct xenbus_device *xbdev; |
| 202 | struct gendisk *gd; |
| 203 | u16 sector_size; |
| 204 | unsigned int physical_sector_size; |
| 205 | unsigned long vdisk_info; |
| 206 | int vdevice; |
| 207 | blkif_vdev_t handle; |
| 208 | enum blkif_state connected; |
| 209 | /* Number of pages per ring buffer. */ |
| 210 | unsigned int nr_ring_pages; |
| 211 | struct request_queue *rq; |
| 212 | unsigned int feature_flush:1; |
| 213 | unsigned int feature_fua:1; |
| 214 | unsigned int feature_discard:1; |
| 215 | unsigned int feature_secdiscard:1; |
| 216 | /* Connect-time cached feature_persistent parameter */ |
| 217 | unsigned int feature_persistent_parm:1; |
| 218 | /* Persistent grants feature negotiation result */ |
| 219 | unsigned int feature_persistent:1; |
| 220 | unsigned int bounce:1; |
| 221 | unsigned int discard_granularity; |
| 222 | unsigned int discard_alignment; |
| 223 | /* Number of 4KB segments handled */ |
| 224 | unsigned int max_indirect_segments; |
| 225 | int is_ready; |
| 226 | struct blk_mq_tag_set tag_set; |
| 227 | struct blkfront_ring_info *rinfo; |
| 228 | unsigned int nr_rings; |
| 229 | unsigned int rinfo_size; |
| 230 | /* Save uncomplete reqs and bios for migration. */ |
| 231 | struct list_head requests; |
| 232 | struct bio_list bio_list; |
| 233 | struct list_head info_list; |
| 234 | }; |
| 235 | |
| 236 | static unsigned int nr_minors; |
| 237 | static unsigned long *minors; |
| 238 | static DEFINE_SPINLOCK(minor_lock); |
| 239 | |
| 240 | #define PARTS_PER_DISK 16 |
| 241 | #define PARTS_PER_EXT_DISK 256 |
| 242 | |
| 243 | #define BLKIF_MAJOR(dev) ((dev)>>8) |
| 244 | #define BLKIF_MINOR(dev) ((dev) & 0xff) |
| 245 | |
| 246 | #define EXT_SHIFT 28 |
| 247 | #define EXTENDED (1<<EXT_SHIFT) |
| 248 | #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) |
| 249 | #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) |
| 250 | #define EMULATED_HD_DISK_MINOR_OFFSET (0) |
| 251 | #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) |
| 252 | #define EMULATED_SD_DISK_MINOR_OFFSET (0) |
| 253 | #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) |
| 254 | |
| 255 | #define DEV_NAME "xvd" /* name in /dev */ |
| 256 | |
| 257 | /* |
| 258 | * Grants are always the same size as a Xen page (i.e 4KB). |
| 259 | * A physical segment is always the same size as a Linux page. |
| 260 | * Number of grants per physical segment |
| 261 | */ |
| 262 | #define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE) |
| 263 | |
| 264 | #define GRANTS_PER_INDIRECT_FRAME \ |
| 265 | (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment)) |
| 266 | |
| 267 | #define INDIRECT_GREFS(_grants) \ |
| 268 | DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME) |
| 269 | |
| 270 | static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo); |
| 271 | static void blkfront_gather_backend_features(struct blkfront_info *info); |
| 272 | static int negotiate_mq(struct blkfront_info *info); |
| 273 | |
| 274 | #define for_each_rinfo(info, ptr, idx) \ |
| 275 | for ((ptr) = (info)->rinfo, (idx) = 0; \ |
| 276 | (idx) < (info)->nr_rings; \ |
| 277 | (idx)++, (ptr) = (void *)(ptr) + (info)->rinfo_size) |
| 278 | |
| 279 | static inline struct blkfront_ring_info * |
| 280 | get_rinfo(const struct blkfront_info *info, unsigned int i) |
| 281 | { |
| 282 | BUG_ON(i >= info->nr_rings); |
| 283 | return (void *)info->rinfo + i * info->rinfo_size; |
| 284 | } |
| 285 | |
| 286 | static int get_id_from_freelist(struct blkfront_ring_info *rinfo) |
| 287 | { |
| 288 | unsigned long free = rinfo->shadow_free; |
| 289 | |
| 290 | BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info)); |
| 291 | rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id; |
| 292 | rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ |
| 293 | return free; |
| 294 | } |
| 295 | |
| 296 | static int add_id_to_freelist(struct blkfront_ring_info *rinfo, |
| 297 | unsigned long id) |
| 298 | { |
| 299 | if (rinfo->shadow[id].req.u.rw.id != id) |
| 300 | return -EINVAL; |
| 301 | if (rinfo->shadow[id].request == NULL) |
| 302 | return -EINVAL; |
| 303 | rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free; |
| 304 | rinfo->shadow[id].request = NULL; |
| 305 | rinfo->shadow_free = id; |
| 306 | return 0; |
| 307 | } |
| 308 | |
| 309 | static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) |
| 310 | { |
| 311 | struct blkfront_info *info = rinfo->dev_info; |
| 312 | struct page *granted_page; |
| 313 | struct grant *gnt_list_entry, *n; |
| 314 | int i = 0; |
| 315 | |
| 316 | while (i < num) { |
| 317 | gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO); |
| 318 | if (!gnt_list_entry) |
| 319 | goto out_of_memory; |
| 320 | |
| 321 | if (info->bounce) { |
| 322 | granted_page = alloc_page(GFP_NOIO | __GFP_ZERO); |
| 323 | if (!granted_page) { |
| 324 | kfree(gnt_list_entry); |
| 325 | goto out_of_memory; |
| 326 | } |
| 327 | gnt_list_entry->page = granted_page; |
| 328 | } |
| 329 | |
| 330 | gnt_list_entry->gref = INVALID_GRANT_REF; |
| 331 | list_add(&gnt_list_entry->node, &rinfo->grants); |
| 332 | i++; |
| 333 | } |
| 334 | |
| 335 | return 0; |
| 336 | |
| 337 | out_of_memory: |
| 338 | list_for_each_entry_safe(gnt_list_entry, n, |
| 339 | &rinfo->grants, node) { |
| 340 | list_del(&gnt_list_entry->node); |
| 341 | if (info->bounce) |
| 342 | __free_page(gnt_list_entry->page); |
| 343 | kfree(gnt_list_entry); |
| 344 | i--; |
| 345 | } |
| 346 | BUG_ON(i != 0); |
| 347 | return -ENOMEM; |
| 348 | } |
| 349 | |
| 350 | static struct grant *get_free_grant(struct blkfront_ring_info *rinfo) |
| 351 | { |
| 352 | struct grant *gnt_list_entry; |
| 353 | |
| 354 | BUG_ON(list_empty(&rinfo->grants)); |
| 355 | gnt_list_entry = list_first_entry(&rinfo->grants, struct grant, |
| 356 | node); |
| 357 | list_del(&gnt_list_entry->node); |
| 358 | |
| 359 | if (gnt_list_entry->gref != INVALID_GRANT_REF) |
| 360 | rinfo->persistent_gnts_c--; |
| 361 | |
| 362 | return gnt_list_entry; |
| 363 | } |
| 364 | |
| 365 | static inline void grant_foreign_access(const struct grant *gnt_list_entry, |
| 366 | const struct blkfront_info *info) |
| 367 | { |
| 368 | gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref, |
| 369 | info->xbdev->otherend_id, |
| 370 | gnt_list_entry->page, |
| 371 | 0); |
| 372 | } |
| 373 | |
| 374 | static struct grant *get_grant(grant_ref_t *gref_head, |
| 375 | unsigned long gfn, |
| 376 | struct blkfront_ring_info *rinfo) |
| 377 | { |
| 378 | struct grant *gnt_list_entry = get_free_grant(rinfo); |
| 379 | struct blkfront_info *info = rinfo->dev_info; |
| 380 | |
| 381 | if (gnt_list_entry->gref != INVALID_GRANT_REF) |
| 382 | return gnt_list_entry; |
| 383 | |
| 384 | /* Assign a gref to this page */ |
| 385 | gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); |
| 386 | BUG_ON(gnt_list_entry->gref == -ENOSPC); |
| 387 | if (info->bounce) |
| 388 | grant_foreign_access(gnt_list_entry, info); |
| 389 | else { |
| 390 | /* Grant access to the GFN passed by the caller */ |
| 391 | gnttab_grant_foreign_access_ref(gnt_list_entry->gref, |
| 392 | info->xbdev->otherend_id, |
| 393 | gfn, 0); |
| 394 | } |
| 395 | |
| 396 | return gnt_list_entry; |
| 397 | } |
| 398 | |
| 399 | static struct grant *get_indirect_grant(grant_ref_t *gref_head, |
| 400 | struct blkfront_ring_info *rinfo) |
| 401 | { |
| 402 | struct grant *gnt_list_entry = get_free_grant(rinfo); |
| 403 | struct blkfront_info *info = rinfo->dev_info; |
| 404 | |
| 405 | if (gnt_list_entry->gref != INVALID_GRANT_REF) |
| 406 | return gnt_list_entry; |
| 407 | |
| 408 | /* Assign a gref to this page */ |
| 409 | gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); |
| 410 | BUG_ON(gnt_list_entry->gref == -ENOSPC); |
| 411 | if (!info->bounce) { |
| 412 | struct page *indirect_page; |
| 413 | |
| 414 | /* Fetch a pre-allocated page to use for indirect grefs */ |
| 415 | BUG_ON(list_empty(&rinfo->indirect_pages)); |
| 416 | indirect_page = list_first_entry(&rinfo->indirect_pages, |
| 417 | struct page, lru); |
| 418 | list_del(&indirect_page->lru); |
| 419 | gnt_list_entry->page = indirect_page; |
| 420 | } |
| 421 | grant_foreign_access(gnt_list_entry, info); |
| 422 | |
| 423 | return gnt_list_entry; |
| 424 | } |
| 425 | |
| 426 | static const char *op_name(int op) |
| 427 | { |
| 428 | static const char *const names[] = { |
| 429 | [BLKIF_OP_READ] = "read", |
| 430 | [BLKIF_OP_WRITE] = "write", |
| 431 | [BLKIF_OP_WRITE_BARRIER] = "barrier", |
| 432 | [BLKIF_OP_FLUSH_DISKCACHE] = "flush", |
| 433 | [BLKIF_OP_DISCARD] = "discard" }; |
| 434 | |
| 435 | if (op < 0 || op >= ARRAY_SIZE(names)) |
| 436 | return "unknown"; |
| 437 | |
| 438 | if (!names[op]) |
| 439 | return "reserved"; |
| 440 | |
| 441 | return names[op]; |
| 442 | } |
| 443 | static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) |
| 444 | { |
| 445 | unsigned int end = minor + nr; |
| 446 | int rc; |
| 447 | |
| 448 | if (end > nr_minors) { |
| 449 | unsigned long *bitmap, *old; |
| 450 | |
| 451 | bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap), |
| 452 | GFP_KERNEL); |
| 453 | if (bitmap == NULL) |
| 454 | return -ENOMEM; |
| 455 | |
| 456 | spin_lock(&minor_lock); |
| 457 | if (end > nr_minors) { |
| 458 | old = minors; |
| 459 | memcpy(bitmap, minors, |
| 460 | BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); |
| 461 | minors = bitmap; |
| 462 | nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; |
| 463 | } else |
| 464 | old = bitmap; |
| 465 | spin_unlock(&minor_lock); |
| 466 | kfree(old); |
| 467 | } |
| 468 | |
| 469 | spin_lock(&minor_lock); |
| 470 | if (find_next_bit(minors, end, minor) >= end) { |
| 471 | bitmap_set(minors, minor, nr); |
| 472 | rc = 0; |
| 473 | } else |
| 474 | rc = -EBUSY; |
| 475 | spin_unlock(&minor_lock); |
| 476 | |
| 477 | return rc; |
| 478 | } |
| 479 | |
| 480 | static void xlbd_release_minors(unsigned int minor, unsigned int nr) |
| 481 | { |
| 482 | unsigned int end = minor + nr; |
| 483 | |
| 484 | BUG_ON(end > nr_minors); |
| 485 | spin_lock(&minor_lock); |
| 486 | bitmap_clear(minors, minor, nr); |
| 487 | spin_unlock(&minor_lock); |
| 488 | } |
| 489 | |
| 490 | static void blkif_restart_queue_callback(void *arg) |
| 491 | { |
| 492 | struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg; |
| 493 | schedule_work(&rinfo->work); |
| 494 | } |
| 495 | |
| 496 | static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) |
| 497 | { |
| 498 | /* We don't have real geometry info, but let's at least return |
| 499 | values consistent with the size of the device */ |
| 500 | sector_t nsect = get_capacity(bd->bd_disk); |
| 501 | sector_t cylinders = nsect; |
| 502 | |
| 503 | hg->heads = 0xff; |
| 504 | hg->sectors = 0x3f; |
| 505 | sector_div(cylinders, hg->heads * hg->sectors); |
| 506 | hg->cylinders = cylinders; |
| 507 | if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) |
| 508 | hg->cylinders = 0xffff; |
| 509 | return 0; |
| 510 | } |
| 511 | |
| 512 | static int blkif_ioctl(struct block_device *bdev, blk_mode_t mode, |
| 513 | unsigned command, unsigned long argument) |
| 514 | { |
| 515 | struct blkfront_info *info = bdev->bd_disk->private_data; |
| 516 | int i; |
| 517 | |
| 518 | switch (command) { |
| 519 | case CDROMMULTISESSION: |
| 520 | for (i = 0; i < sizeof(struct cdrom_multisession); i++) |
| 521 | if (put_user(0, (char __user *)(argument + i))) |
| 522 | return -EFAULT; |
| 523 | return 0; |
| 524 | case CDROM_GET_CAPABILITY: |
| 525 | if (!(info->vdisk_info & VDISK_CDROM)) |
| 526 | return -EINVAL; |
| 527 | return 0; |
| 528 | default: |
| 529 | return -EINVAL; |
| 530 | } |
| 531 | } |
| 532 | |
| 533 | static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo, |
| 534 | struct request *req, |
| 535 | struct blkif_request **ring_req) |
| 536 | { |
| 537 | unsigned long id; |
| 538 | |
| 539 | *ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt); |
| 540 | rinfo->ring.req_prod_pvt++; |
| 541 | |
| 542 | id = get_id_from_freelist(rinfo); |
| 543 | rinfo->shadow[id].request = req; |
| 544 | rinfo->shadow[id].status = REQ_PROCESSING; |
| 545 | rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID; |
| 546 | |
| 547 | rinfo->shadow[id].req.u.rw.id = id; |
| 548 | |
| 549 | return id; |
| 550 | } |
| 551 | |
| 552 | static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo) |
| 553 | { |
| 554 | struct blkfront_info *info = rinfo->dev_info; |
| 555 | struct blkif_request *ring_req, *final_ring_req; |
| 556 | unsigned long id; |
| 557 | |
| 558 | /* Fill out a communications ring structure. */ |
| 559 | id = blkif_ring_get_request(rinfo, req, &final_ring_req); |
| 560 | ring_req = &rinfo->shadow[id].req; |
| 561 | |
| 562 | ring_req->operation = BLKIF_OP_DISCARD; |
| 563 | ring_req->u.discard.nr_sectors = blk_rq_sectors(req); |
| 564 | ring_req->u.discard.id = id; |
| 565 | ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); |
| 566 | if (req_op(req) == REQ_OP_SECURE_ERASE && info->feature_secdiscard) |
| 567 | ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; |
| 568 | else |
| 569 | ring_req->u.discard.flag = 0; |
| 570 | |
| 571 | /* Copy the request to the ring page. */ |
| 572 | *final_ring_req = *ring_req; |
| 573 | rinfo->shadow[id].status = REQ_WAITING; |
| 574 | |
| 575 | return 0; |
| 576 | } |
| 577 | |
| 578 | struct setup_rw_req { |
| 579 | unsigned int grant_idx; |
| 580 | struct blkif_request_segment *segments; |
| 581 | struct blkfront_ring_info *rinfo; |
| 582 | struct blkif_request *ring_req; |
| 583 | grant_ref_t gref_head; |
| 584 | unsigned int id; |
| 585 | /* Only used when persistent grant is used and it's a write request */ |
| 586 | bool need_copy; |
| 587 | unsigned int bvec_off; |
| 588 | char *bvec_data; |
| 589 | |
| 590 | bool require_extra_req; |
| 591 | struct blkif_request *extra_ring_req; |
| 592 | }; |
| 593 | |
| 594 | static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset, |
| 595 | unsigned int len, void *data) |
| 596 | { |
| 597 | struct setup_rw_req *setup = data; |
| 598 | int n, ref; |
| 599 | struct grant *gnt_list_entry; |
| 600 | unsigned int fsect, lsect; |
| 601 | /* Convenient aliases */ |
| 602 | unsigned int grant_idx = setup->grant_idx; |
| 603 | struct blkif_request *ring_req = setup->ring_req; |
| 604 | struct blkfront_ring_info *rinfo = setup->rinfo; |
| 605 | /* |
| 606 | * We always use the shadow of the first request to store the list |
| 607 | * of grant associated to the block I/O request. This made the |
| 608 | * completion more easy to handle even if the block I/O request is |
| 609 | * split. |
| 610 | */ |
| 611 | struct blk_shadow *shadow = &rinfo->shadow[setup->id]; |
| 612 | |
| 613 | if (unlikely(setup->require_extra_req && |
| 614 | grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) { |
| 615 | /* |
| 616 | * We are using the second request, setup grant_idx |
| 617 | * to be the index of the segment array. |
| 618 | */ |
| 619 | grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 620 | ring_req = setup->extra_ring_req; |
| 621 | } |
| 622 | |
| 623 | if ((ring_req->operation == BLKIF_OP_INDIRECT) && |
| 624 | (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) { |
| 625 | if (setup->segments) |
| 626 | kunmap_atomic(setup->segments); |
| 627 | |
| 628 | n = grant_idx / GRANTS_PER_INDIRECT_FRAME; |
| 629 | gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo); |
| 630 | shadow->indirect_grants[n] = gnt_list_entry; |
| 631 | setup->segments = kmap_atomic(gnt_list_entry->page); |
| 632 | ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; |
| 633 | } |
| 634 | |
| 635 | gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo); |
| 636 | ref = gnt_list_entry->gref; |
| 637 | /* |
| 638 | * All the grants are stored in the shadow of the first |
| 639 | * request. Therefore we have to use the global index. |
| 640 | */ |
| 641 | shadow->grants_used[setup->grant_idx] = gnt_list_entry; |
| 642 | |
| 643 | if (setup->need_copy) { |
| 644 | void *shared_data; |
| 645 | |
| 646 | shared_data = kmap_atomic(gnt_list_entry->page); |
| 647 | /* |
| 648 | * this does not wipe data stored outside the |
| 649 | * range sg->offset..sg->offset+sg->length. |
| 650 | * Therefore, blkback *could* see data from |
| 651 | * previous requests. This is OK as long as |
| 652 | * persistent grants are shared with just one |
| 653 | * domain. It may need refactoring if this |
| 654 | * changes |
| 655 | */ |
| 656 | memcpy(shared_data + offset, |
| 657 | setup->bvec_data + setup->bvec_off, |
| 658 | len); |
| 659 | |
| 660 | kunmap_atomic(shared_data); |
| 661 | setup->bvec_off += len; |
| 662 | } |
| 663 | |
| 664 | fsect = offset >> 9; |
| 665 | lsect = fsect + (len >> 9) - 1; |
| 666 | if (ring_req->operation != BLKIF_OP_INDIRECT) { |
| 667 | ring_req->u.rw.seg[grant_idx] = |
| 668 | (struct blkif_request_segment) { |
| 669 | .gref = ref, |
| 670 | .first_sect = fsect, |
| 671 | .last_sect = lsect }; |
| 672 | } else { |
| 673 | setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] = |
| 674 | (struct blkif_request_segment) { |
| 675 | .gref = ref, |
| 676 | .first_sect = fsect, |
| 677 | .last_sect = lsect }; |
| 678 | } |
| 679 | |
| 680 | (setup->grant_idx)++; |
| 681 | } |
| 682 | |
| 683 | static void blkif_setup_extra_req(struct blkif_request *first, |
| 684 | struct blkif_request *second) |
| 685 | { |
| 686 | uint16_t nr_segments = first->u.rw.nr_segments; |
| 687 | |
| 688 | /* |
| 689 | * The second request is only present when the first request uses |
| 690 | * all its segments. It's always the continuity of the first one. |
| 691 | */ |
| 692 | first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 693 | |
| 694 | second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 695 | second->u.rw.sector_number = first->u.rw.sector_number + |
| 696 | (BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512; |
| 697 | |
| 698 | second->u.rw.handle = first->u.rw.handle; |
| 699 | second->operation = first->operation; |
| 700 | } |
| 701 | |
| 702 | static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo) |
| 703 | { |
| 704 | struct blkfront_info *info = rinfo->dev_info; |
| 705 | struct blkif_request *ring_req, *extra_ring_req = NULL; |
| 706 | struct blkif_request *final_ring_req, *final_extra_ring_req = NULL; |
| 707 | unsigned long id, extra_id = NO_ASSOCIATED_ID; |
| 708 | bool require_extra_req = false; |
| 709 | int i; |
| 710 | struct setup_rw_req setup = { |
| 711 | .grant_idx = 0, |
| 712 | .segments = NULL, |
| 713 | .rinfo = rinfo, |
| 714 | .need_copy = rq_data_dir(req) && info->bounce, |
| 715 | }; |
| 716 | |
| 717 | /* |
| 718 | * Used to store if we are able to queue the request by just using |
| 719 | * existing persistent grants, or if we have to get new grants, |
| 720 | * as there are not sufficiently many free. |
| 721 | */ |
| 722 | bool new_persistent_gnts = false; |
| 723 | struct scatterlist *sg; |
| 724 | int num_sg, max_grefs, num_grant; |
| 725 | |
| 726 | max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG; |
| 727 | if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST) |
| 728 | /* |
| 729 | * If we are using indirect segments we need to account |
| 730 | * for the indirect grefs used in the request. |
| 731 | */ |
| 732 | max_grefs += INDIRECT_GREFS(max_grefs); |
| 733 | |
| 734 | /* Check if we have enough persistent grants to allocate a requests */ |
| 735 | if (rinfo->persistent_gnts_c < max_grefs) { |
| 736 | new_persistent_gnts = true; |
| 737 | |
| 738 | if (gnttab_alloc_grant_references( |
| 739 | max_grefs - rinfo->persistent_gnts_c, |
| 740 | &setup.gref_head) < 0) { |
| 741 | gnttab_request_free_callback( |
| 742 | &rinfo->callback, |
| 743 | blkif_restart_queue_callback, |
| 744 | rinfo, |
| 745 | max_grefs - rinfo->persistent_gnts_c); |
| 746 | return 1; |
| 747 | } |
| 748 | } |
| 749 | |
| 750 | /* Fill out a communications ring structure. */ |
| 751 | id = blkif_ring_get_request(rinfo, req, &final_ring_req); |
| 752 | ring_req = &rinfo->shadow[id].req; |
| 753 | |
| 754 | num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg); |
| 755 | num_grant = 0; |
| 756 | /* Calculate the number of grant used */ |
| 757 | for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) |
| 758 | num_grant += gnttab_count_grant(sg->offset, sg->length); |
| 759 | |
| 760 | require_extra_req = info->max_indirect_segments == 0 && |
| 761 | num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 762 | BUG_ON(!HAS_EXTRA_REQ && require_extra_req); |
| 763 | |
| 764 | rinfo->shadow[id].num_sg = num_sg; |
| 765 | if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST && |
| 766 | likely(!require_extra_req)) { |
| 767 | /* |
| 768 | * The indirect operation can only be a BLKIF_OP_READ or |
| 769 | * BLKIF_OP_WRITE |
| 770 | */ |
| 771 | BUG_ON(req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA); |
| 772 | ring_req->operation = BLKIF_OP_INDIRECT; |
| 773 | ring_req->u.indirect.indirect_op = rq_data_dir(req) ? |
| 774 | BLKIF_OP_WRITE : BLKIF_OP_READ; |
| 775 | ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); |
| 776 | ring_req->u.indirect.handle = info->handle; |
| 777 | ring_req->u.indirect.nr_segments = num_grant; |
| 778 | } else { |
| 779 | ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); |
| 780 | ring_req->u.rw.handle = info->handle; |
| 781 | ring_req->operation = rq_data_dir(req) ? |
| 782 | BLKIF_OP_WRITE : BLKIF_OP_READ; |
| 783 | if (req_op(req) == REQ_OP_FLUSH || |
| 784 | (req_op(req) == REQ_OP_WRITE && (req->cmd_flags & REQ_FUA))) { |
| 785 | /* |
| 786 | * Ideally we can do an unordered flush-to-disk. |
| 787 | * In case the backend onlysupports barriers, use that. |
| 788 | * A barrier request a superset of FUA, so we can |
| 789 | * implement it the same way. (It's also a FLUSH+FUA, |
| 790 | * since it is guaranteed ordered WRT previous writes.) |
| 791 | */ |
| 792 | if (info->feature_flush && info->feature_fua) |
| 793 | ring_req->operation = |
| 794 | BLKIF_OP_WRITE_BARRIER; |
| 795 | else if (info->feature_flush) |
| 796 | ring_req->operation = |
| 797 | BLKIF_OP_FLUSH_DISKCACHE; |
| 798 | else |
| 799 | ring_req->operation = 0; |
| 800 | } |
| 801 | ring_req->u.rw.nr_segments = num_grant; |
| 802 | if (unlikely(require_extra_req)) { |
| 803 | extra_id = blkif_ring_get_request(rinfo, req, |
| 804 | &final_extra_ring_req); |
| 805 | extra_ring_req = &rinfo->shadow[extra_id].req; |
| 806 | |
| 807 | /* |
| 808 | * Only the first request contains the scatter-gather |
| 809 | * list. |
| 810 | */ |
| 811 | rinfo->shadow[extra_id].num_sg = 0; |
| 812 | |
| 813 | blkif_setup_extra_req(ring_req, extra_ring_req); |
| 814 | |
| 815 | /* Link the 2 requests together */ |
| 816 | rinfo->shadow[extra_id].associated_id = id; |
| 817 | rinfo->shadow[id].associated_id = extra_id; |
| 818 | } |
| 819 | } |
| 820 | |
| 821 | setup.ring_req = ring_req; |
| 822 | setup.id = id; |
| 823 | |
| 824 | setup.require_extra_req = require_extra_req; |
| 825 | if (unlikely(require_extra_req)) |
| 826 | setup.extra_ring_req = extra_ring_req; |
| 827 | |
| 828 | for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) { |
| 829 | BUG_ON(sg->offset + sg->length > PAGE_SIZE); |
| 830 | |
| 831 | if (setup.need_copy) { |
| 832 | setup.bvec_off = sg->offset; |
| 833 | setup.bvec_data = kmap_atomic(sg_page(sg)); |
| 834 | } |
| 835 | |
| 836 | gnttab_foreach_grant_in_range(sg_page(sg), |
| 837 | sg->offset, |
| 838 | sg->length, |
| 839 | blkif_setup_rw_req_grant, |
| 840 | &setup); |
| 841 | |
| 842 | if (setup.need_copy) |
| 843 | kunmap_atomic(setup.bvec_data); |
| 844 | } |
| 845 | if (setup.segments) |
| 846 | kunmap_atomic(setup.segments); |
| 847 | |
| 848 | /* Copy request(s) to the ring page. */ |
| 849 | *final_ring_req = *ring_req; |
| 850 | rinfo->shadow[id].status = REQ_WAITING; |
| 851 | if (unlikely(require_extra_req)) { |
| 852 | *final_extra_ring_req = *extra_ring_req; |
| 853 | rinfo->shadow[extra_id].status = REQ_WAITING; |
| 854 | } |
| 855 | |
| 856 | if (new_persistent_gnts) |
| 857 | gnttab_free_grant_references(setup.gref_head); |
| 858 | |
| 859 | return 0; |
| 860 | } |
| 861 | |
| 862 | /* |
| 863 | * Generate a Xen blkfront IO request from a blk layer request. Reads |
| 864 | * and writes are handled as expected. |
| 865 | * |
| 866 | * @req: a request struct |
| 867 | */ |
| 868 | static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo) |
| 869 | { |
| 870 | if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED)) |
| 871 | return 1; |
| 872 | |
| 873 | if (unlikely(req_op(req) == REQ_OP_DISCARD || |
| 874 | req_op(req) == REQ_OP_SECURE_ERASE)) |
| 875 | return blkif_queue_discard_req(req, rinfo); |
| 876 | else |
| 877 | return blkif_queue_rw_req(req, rinfo); |
| 878 | } |
| 879 | |
| 880 | static inline void flush_requests(struct blkfront_ring_info *rinfo) |
| 881 | { |
| 882 | int notify; |
| 883 | |
| 884 | RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify); |
| 885 | |
| 886 | if (notify) |
| 887 | notify_remote_via_irq(rinfo->irq); |
| 888 | } |
| 889 | |
| 890 | static inline bool blkif_request_flush_invalid(struct request *req, |
| 891 | struct blkfront_info *info) |
| 892 | { |
| 893 | return (blk_rq_is_passthrough(req) || |
| 894 | ((req_op(req) == REQ_OP_FLUSH) && |
| 895 | !info->feature_flush) || |
| 896 | ((req->cmd_flags & REQ_FUA) && |
| 897 | !info->feature_fua)); |
| 898 | } |
| 899 | |
| 900 | static blk_status_t blkif_queue_rq(struct blk_mq_hw_ctx *hctx, |
| 901 | const struct blk_mq_queue_data *qd) |
| 902 | { |
| 903 | unsigned long flags; |
| 904 | int qid = hctx->queue_num; |
| 905 | struct blkfront_info *info = hctx->queue->queuedata; |
| 906 | struct blkfront_ring_info *rinfo = NULL; |
| 907 | |
| 908 | rinfo = get_rinfo(info, qid); |
| 909 | blk_mq_start_request(qd->rq); |
| 910 | spin_lock_irqsave(&rinfo->ring_lock, flags); |
| 911 | if (RING_FULL(&rinfo->ring)) |
| 912 | goto out_busy; |
| 913 | |
| 914 | if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info)) |
| 915 | goto out_err; |
| 916 | |
| 917 | if (blkif_queue_request(qd->rq, rinfo)) |
| 918 | goto out_busy; |
| 919 | |
| 920 | flush_requests(rinfo); |
| 921 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 922 | return BLK_STS_OK; |
| 923 | |
| 924 | out_err: |
| 925 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 926 | return BLK_STS_IOERR; |
| 927 | |
| 928 | out_busy: |
| 929 | blk_mq_stop_hw_queue(hctx); |
| 930 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 931 | return BLK_STS_DEV_RESOURCE; |
| 932 | } |
| 933 | |
| 934 | static void blkif_complete_rq(struct request *rq) |
| 935 | { |
| 936 | blk_mq_end_request(rq, blkif_req(rq)->error); |
| 937 | } |
| 938 | |
| 939 | static const struct blk_mq_ops blkfront_mq_ops = { |
| 940 | .queue_rq = blkif_queue_rq, |
| 941 | .complete = blkif_complete_rq, |
| 942 | }; |
| 943 | |
| 944 | static void blkif_set_queue_limits(struct blkfront_info *info) |
| 945 | { |
| 946 | struct request_queue *rq = info->rq; |
| 947 | struct gendisk *gd = info->gd; |
| 948 | unsigned int segments = info->max_indirect_segments ? : |
| 949 | BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 950 | |
| 951 | blk_queue_flag_set(QUEUE_FLAG_VIRT, rq); |
| 952 | |
| 953 | if (info->feature_discard) { |
| 954 | blk_queue_max_discard_sectors(rq, get_capacity(gd)); |
| 955 | rq->limits.discard_granularity = info->discard_granularity ?: |
| 956 | info->physical_sector_size; |
| 957 | rq->limits.discard_alignment = info->discard_alignment; |
| 958 | if (info->feature_secdiscard) |
| 959 | blk_queue_max_secure_erase_sectors(rq, |
| 960 | get_capacity(gd)); |
| 961 | } |
| 962 | |
| 963 | /* Hard sector size and max sectors impersonate the equiv. hardware. */ |
| 964 | blk_queue_logical_block_size(rq, info->sector_size); |
| 965 | blk_queue_physical_block_size(rq, info->physical_sector_size); |
| 966 | blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512); |
| 967 | |
| 968 | /* Each segment in a request is up to an aligned page in size. */ |
| 969 | blk_queue_segment_boundary(rq, PAGE_SIZE - 1); |
| 970 | blk_queue_max_segment_size(rq, PAGE_SIZE); |
| 971 | |
| 972 | /* Ensure a merged request will fit in a single I/O ring slot. */ |
| 973 | blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG); |
| 974 | |
| 975 | /* Make sure buffer addresses are sector-aligned. */ |
| 976 | blk_queue_dma_alignment(rq, 511); |
| 977 | } |
| 978 | |
| 979 | static const char *flush_info(struct blkfront_info *info) |
| 980 | { |
| 981 | if (info->feature_flush && info->feature_fua) |
| 982 | return "barrier: enabled;"; |
| 983 | else if (info->feature_flush) |
| 984 | return "flush diskcache: enabled;"; |
| 985 | else |
| 986 | return "barrier or flush: disabled;"; |
| 987 | } |
| 988 | |
| 989 | static void xlvbd_flush(struct blkfront_info *info) |
| 990 | { |
| 991 | blk_queue_write_cache(info->rq, info->feature_flush ? true : false, |
| 992 | info->feature_fua ? true : false); |
| 993 | pr_info("blkfront: %s: %s %s %s %s %s %s %s\n", |
| 994 | info->gd->disk_name, flush_info(info), |
| 995 | "persistent grants:", info->feature_persistent ? |
| 996 | "enabled;" : "disabled;", "indirect descriptors:", |
| 997 | info->max_indirect_segments ? "enabled;" : "disabled;", |
| 998 | "bounce buffer:", info->bounce ? "enabled" : "disabled;"); |
| 999 | } |
| 1000 | |
| 1001 | static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) |
| 1002 | { |
| 1003 | int major; |
| 1004 | major = BLKIF_MAJOR(vdevice); |
| 1005 | *minor = BLKIF_MINOR(vdevice); |
| 1006 | switch (major) { |
| 1007 | case XEN_IDE0_MAJOR: |
| 1008 | *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; |
| 1009 | *minor = ((*minor / 64) * PARTS_PER_DISK) + |
| 1010 | EMULATED_HD_DISK_MINOR_OFFSET; |
| 1011 | break; |
| 1012 | case XEN_IDE1_MAJOR: |
| 1013 | *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; |
| 1014 | *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + |
| 1015 | EMULATED_HD_DISK_MINOR_OFFSET; |
| 1016 | break; |
| 1017 | case XEN_SCSI_DISK0_MAJOR: |
| 1018 | *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; |
| 1019 | *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; |
| 1020 | break; |
| 1021 | case XEN_SCSI_DISK1_MAJOR: |
| 1022 | case XEN_SCSI_DISK2_MAJOR: |
| 1023 | case XEN_SCSI_DISK3_MAJOR: |
| 1024 | case XEN_SCSI_DISK4_MAJOR: |
| 1025 | case XEN_SCSI_DISK5_MAJOR: |
| 1026 | case XEN_SCSI_DISK6_MAJOR: |
| 1027 | case XEN_SCSI_DISK7_MAJOR: |
| 1028 | *offset = (*minor / PARTS_PER_DISK) + |
| 1029 | ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + |
| 1030 | EMULATED_SD_DISK_NAME_OFFSET; |
| 1031 | *minor = *minor + |
| 1032 | ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + |
| 1033 | EMULATED_SD_DISK_MINOR_OFFSET; |
| 1034 | break; |
| 1035 | case XEN_SCSI_DISK8_MAJOR: |
| 1036 | case XEN_SCSI_DISK9_MAJOR: |
| 1037 | case XEN_SCSI_DISK10_MAJOR: |
| 1038 | case XEN_SCSI_DISK11_MAJOR: |
| 1039 | case XEN_SCSI_DISK12_MAJOR: |
| 1040 | case XEN_SCSI_DISK13_MAJOR: |
| 1041 | case XEN_SCSI_DISK14_MAJOR: |
| 1042 | case XEN_SCSI_DISK15_MAJOR: |
| 1043 | *offset = (*minor / PARTS_PER_DISK) + |
| 1044 | ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + |
| 1045 | EMULATED_SD_DISK_NAME_OFFSET; |
| 1046 | *minor = *minor + |
| 1047 | ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + |
| 1048 | EMULATED_SD_DISK_MINOR_OFFSET; |
| 1049 | break; |
| 1050 | case XENVBD_MAJOR: |
| 1051 | *offset = *minor / PARTS_PER_DISK; |
| 1052 | break; |
| 1053 | default: |
| 1054 | printk(KERN_WARNING "blkfront: your disk configuration is " |
| 1055 | "incorrect, please use an xvd device instead\n"); |
| 1056 | return -ENODEV; |
| 1057 | } |
| 1058 | return 0; |
| 1059 | } |
| 1060 | |
| 1061 | static char *encode_disk_name(char *ptr, unsigned int n) |
| 1062 | { |
| 1063 | if (n >= 26) |
| 1064 | ptr = encode_disk_name(ptr, n / 26 - 1); |
| 1065 | *ptr = 'a' + n % 26; |
| 1066 | return ptr + 1; |
| 1067 | } |
| 1068 | |
| 1069 | static int xlvbd_alloc_gendisk(blkif_sector_t capacity, |
| 1070 | struct blkfront_info *info, u16 sector_size, |
| 1071 | unsigned int physical_sector_size) |
| 1072 | { |
| 1073 | struct gendisk *gd; |
| 1074 | int nr_minors = 1; |
| 1075 | int err; |
| 1076 | unsigned int offset; |
| 1077 | int minor; |
| 1078 | int nr_parts; |
| 1079 | char *ptr; |
| 1080 | |
| 1081 | BUG_ON(info->gd != NULL); |
| 1082 | BUG_ON(info->rq != NULL); |
| 1083 | |
| 1084 | if ((info->vdevice>>EXT_SHIFT) > 1) { |
| 1085 | /* this is above the extended range; something is wrong */ |
| 1086 | printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); |
| 1087 | return -ENODEV; |
| 1088 | } |
| 1089 | |
| 1090 | if (!VDEV_IS_EXTENDED(info->vdevice)) { |
| 1091 | err = xen_translate_vdev(info->vdevice, &minor, &offset); |
| 1092 | if (err) |
| 1093 | return err; |
| 1094 | nr_parts = PARTS_PER_DISK; |
| 1095 | } else { |
| 1096 | minor = BLKIF_MINOR_EXT(info->vdevice); |
| 1097 | nr_parts = PARTS_PER_EXT_DISK; |
| 1098 | offset = minor / nr_parts; |
| 1099 | if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) |
| 1100 | printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " |
| 1101 | "emulated IDE disks,\n\t choose an xvd device name" |
| 1102 | "from xvde on\n", info->vdevice); |
| 1103 | } |
| 1104 | if (minor >> MINORBITS) { |
| 1105 | pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n", |
| 1106 | info->vdevice, minor); |
| 1107 | return -ENODEV; |
| 1108 | } |
| 1109 | |
| 1110 | if ((minor % nr_parts) == 0) |
| 1111 | nr_minors = nr_parts; |
| 1112 | |
| 1113 | err = xlbd_reserve_minors(minor, nr_minors); |
| 1114 | if (err) |
| 1115 | return err; |
| 1116 | |
| 1117 | memset(&info->tag_set, 0, sizeof(info->tag_set)); |
| 1118 | info->tag_set.ops = &blkfront_mq_ops; |
| 1119 | info->tag_set.nr_hw_queues = info->nr_rings; |
| 1120 | if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) { |
| 1121 | /* |
| 1122 | * When indirect descriptior is not supported, the I/O request |
| 1123 | * will be split between multiple request in the ring. |
| 1124 | * To avoid problems when sending the request, divide by |
| 1125 | * 2 the depth of the queue. |
| 1126 | */ |
| 1127 | info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2; |
| 1128 | } else |
| 1129 | info->tag_set.queue_depth = BLK_RING_SIZE(info); |
| 1130 | info->tag_set.numa_node = NUMA_NO_NODE; |
| 1131 | info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; |
| 1132 | info->tag_set.cmd_size = sizeof(struct blkif_req); |
| 1133 | info->tag_set.driver_data = info; |
| 1134 | |
| 1135 | err = blk_mq_alloc_tag_set(&info->tag_set); |
| 1136 | if (err) |
| 1137 | goto out_release_minors; |
| 1138 | |
| 1139 | gd = blk_mq_alloc_disk(&info->tag_set, info); |
| 1140 | if (IS_ERR(gd)) { |
| 1141 | err = PTR_ERR(gd); |
| 1142 | goto out_free_tag_set; |
| 1143 | } |
| 1144 | |
| 1145 | strcpy(gd->disk_name, DEV_NAME); |
| 1146 | ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset); |
| 1147 | BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN); |
| 1148 | if (nr_minors > 1) |
| 1149 | *ptr = 0; |
| 1150 | else |
| 1151 | snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr, |
| 1152 | "%d", minor & (nr_parts - 1)); |
| 1153 | |
| 1154 | gd->major = XENVBD_MAJOR; |
| 1155 | gd->first_minor = minor; |
| 1156 | gd->minors = nr_minors; |
| 1157 | gd->fops = &xlvbd_block_fops; |
| 1158 | gd->private_data = info; |
| 1159 | set_capacity(gd, capacity); |
| 1160 | |
| 1161 | info->rq = gd->queue; |
| 1162 | info->gd = gd; |
| 1163 | info->sector_size = sector_size; |
| 1164 | info->physical_sector_size = physical_sector_size; |
| 1165 | blkif_set_queue_limits(info); |
| 1166 | |
| 1167 | xlvbd_flush(info); |
| 1168 | |
| 1169 | if (info->vdisk_info & VDISK_READONLY) |
| 1170 | set_disk_ro(gd, 1); |
| 1171 | if (info->vdisk_info & VDISK_REMOVABLE) |
| 1172 | gd->flags |= GENHD_FL_REMOVABLE; |
| 1173 | |
| 1174 | return 0; |
| 1175 | |
| 1176 | out_free_tag_set: |
| 1177 | blk_mq_free_tag_set(&info->tag_set); |
| 1178 | out_release_minors: |
| 1179 | xlbd_release_minors(minor, nr_minors); |
| 1180 | return err; |
| 1181 | } |
| 1182 | |
| 1183 | /* Already hold rinfo->ring_lock. */ |
| 1184 | static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) |
| 1185 | { |
| 1186 | if (!RING_FULL(&rinfo->ring)) |
| 1187 | blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); |
| 1188 | } |
| 1189 | |
| 1190 | static void kick_pending_request_queues(struct blkfront_ring_info *rinfo) |
| 1191 | { |
| 1192 | unsigned long flags; |
| 1193 | |
| 1194 | spin_lock_irqsave(&rinfo->ring_lock, flags); |
| 1195 | kick_pending_request_queues_locked(rinfo); |
| 1196 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 1197 | } |
| 1198 | |
| 1199 | static void blkif_restart_queue(struct work_struct *work) |
| 1200 | { |
| 1201 | struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work); |
| 1202 | |
| 1203 | if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED) |
| 1204 | kick_pending_request_queues(rinfo); |
| 1205 | } |
| 1206 | |
| 1207 | static void blkif_free_ring(struct blkfront_ring_info *rinfo) |
| 1208 | { |
| 1209 | struct grant *persistent_gnt, *n; |
| 1210 | struct blkfront_info *info = rinfo->dev_info; |
| 1211 | int i, j, segs; |
| 1212 | |
| 1213 | /* |
| 1214 | * Remove indirect pages, this only happens when using indirect |
| 1215 | * descriptors but not persistent grants |
| 1216 | */ |
| 1217 | if (!list_empty(&rinfo->indirect_pages)) { |
| 1218 | struct page *indirect_page, *n; |
| 1219 | |
| 1220 | BUG_ON(info->bounce); |
| 1221 | list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { |
| 1222 | list_del(&indirect_page->lru); |
| 1223 | __free_page(indirect_page); |
| 1224 | } |
| 1225 | } |
| 1226 | |
| 1227 | /* Remove all persistent grants. */ |
| 1228 | if (!list_empty(&rinfo->grants)) { |
| 1229 | list_for_each_entry_safe(persistent_gnt, n, |
| 1230 | &rinfo->grants, node) { |
| 1231 | list_del(&persistent_gnt->node); |
| 1232 | if (persistent_gnt->gref != INVALID_GRANT_REF) { |
| 1233 | gnttab_end_foreign_access(persistent_gnt->gref, |
| 1234 | NULL); |
| 1235 | rinfo->persistent_gnts_c--; |
| 1236 | } |
| 1237 | if (info->bounce) |
| 1238 | __free_page(persistent_gnt->page); |
| 1239 | kfree(persistent_gnt); |
| 1240 | } |
| 1241 | } |
| 1242 | BUG_ON(rinfo->persistent_gnts_c != 0); |
| 1243 | |
| 1244 | for (i = 0; i < BLK_RING_SIZE(info); i++) { |
| 1245 | /* |
| 1246 | * Clear persistent grants present in requests already |
| 1247 | * on the shared ring |
| 1248 | */ |
| 1249 | if (!rinfo->shadow[i].request) |
| 1250 | goto free_shadow; |
| 1251 | |
| 1252 | segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ? |
| 1253 | rinfo->shadow[i].req.u.indirect.nr_segments : |
| 1254 | rinfo->shadow[i].req.u.rw.nr_segments; |
| 1255 | for (j = 0; j < segs; j++) { |
| 1256 | persistent_gnt = rinfo->shadow[i].grants_used[j]; |
| 1257 | gnttab_end_foreign_access(persistent_gnt->gref, NULL); |
| 1258 | if (info->bounce) |
| 1259 | __free_page(persistent_gnt->page); |
| 1260 | kfree(persistent_gnt); |
| 1261 | } |
| 1262 | |
| 1263 | if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT) |
| 1264 | /* |
| 1265 | * If this is not an indirect operation don't try to |
| 1266 | * free indirect segments |
| 1267 | */ |
| 1268 | goto free_shadow; |
| 1269 | |
| 1270 | for (j = 0; j < INDIRECT_GREFS(segs); j++) { |
| 1271 | persistent_gnt = rinfo->shadow[i].indirect_grants[j]; |
| 1272 | gnttab_end_foreign_access(persistent_gnt->gref, NULL); |
| 1273 | __free_page(persistent_gnt->page); |
| 1274 | kfree(persistent_gnt); |
| 1275 | } |
| 1276 | |
| 1277 | free_shadow: |
| 1278 | kvfree(rinfo->shadow[i].grants_used); |
| 1279 | rinfo->shadow[i].grants_used = NULL; |
| 1280 | kvfree(rinfo->shadow[i].indirect_grants); |
| 1281 | rinfo->shadow[i].indirect_grants = NULL; |
| 1282 | kvfree(rinfo->shadow[i].sg); |
| 1283 | rinfo->shadow[i].sg = NULL; |
| 1284 | } |
| 1285 | |
| 1286 | /* No more gnttab callback work. */ |
| 1287 | gnttab_cancel_free_callback(&rinfo->callback); |
| 1288 | |
| 1289 | /* Flush gnttab callback work. Must be done with no locks held. */ |
| 1290 | flush_work(&rinfo->work); |
| 1291 | |
| 1292 | /* Free resources associated with old device channel. */ |
| 1293 | xenbus_teardown_ring((void **)&rinfo->ring.sring, info->nr_ring_pages, |
| 1294 | rinfo->ring_ref); |
| 1295 | |
| 1296 | if (rinfo->irq) |
| 1297 | unbind_from_irqhandler(rinfo->irq, rinfo); |
| 1298 | rinfo->evtchn = rinfo->irq = 0; |
| 1299 | } |
| 1300 | |
| 1301 | static void blkif_free(struct blkfront_info *info, int suspend) |
| 1302 | { |
| 1303 | unsigned int i; |
| 1304 | struct blkfront_ring_info *rinfo; |
| 1305 | |
| 1306 | /* Prevent new requests being issued until we fix things up. */ |
| 1307 | info->connected = suspend ? |
| 1308 | BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; |
| 1309 | /* No more blkif_request(). */ |
| 1310 | if (info->rq) |
| 1311 | blk_mq_stop_hw_queues(info->rq); |
| 1312 | |
| 1313 | for_each_rinfo(info, rinfo, i) |
| 1314 | blkif_free_ring(rinfo); |
| 1315 | |
| 1316 | kvfree(info->rinfo); |
| 1317 | info->rinfo = NULL; |
| 1318 | info->nr_rings = 0; |
| 1319 | } |
| 1320 | |
| 1321 | struct copy_from_grant { |
| 1322 | const struct blk_shadow *s; |
| 1323 | unsigned int grant_idx; |
| 1324 | unsigned int bvec_offset; |
| 1325 | char *bvec_data; |
| 1326 | }; |
| 1327 | |
| 1328 | static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset, |
| 1329 | unsigned int len, void *data) |
| 1330 | { |
| 1331 | struct copy_from_grant *info = data; |
| 1332 | char *shared_data; |
| 1333 | /* Convenient aliases */ |
| 1334 | const struct blk_shadow *s = info->s; |
| 1335 | |
| 1336 | shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page); |
| 1337 | |
| 1338 | memcpy(info->bvec_data + info->bvec_offset, |
| 1339 | shared_data + offset, len); |
| 1340 | |
| 1341 | info->bvec_offset += len; |
| 1342 | info->grant_idx++; |
| 1343 | |
| 1344 | kunmap_atomic(shared_data); |
| 1345 | } |
| 1346 | |
| 1347 | static enum blk_req_status blkif_rsp_to_req_status(int rsp) |
| 1348 | { |
| 1349 | switch (rsp) |
| 1350 | { |
| 1351 | case BLKIF_RSP_OKAY: |
| 1352 | return REQ_DONE; |
| 1353 | case BLKIF_RSP_EOPNOTSUPP: |
| 1354 | return REQ_EOPNOTSUPP; |
| 1355 | case BLKIF_RSP_ERROR: |
| 1356 | default: |
| 1357 | return REQ_ERROR; |
| 1358 | } |
| 1359 | } |
| 1360 | |
| 1361 | /* |
| 1362 | * Get the final status of the block request based on two ring response |
| 1363 | */ |
| 1364 | static int blkif_get_final_status(enum blk_req_status s1, |
| 1365 | enum blk_req_status s2) |
| 1366 | { |
| 1367 | BUG_ON(s1 < REQ_DONE); |
| 1368 | BUG_ON(s2 < REQ_DONE); |
| 1369 | |
| 1370 | if (s1 == REQ_ERROR || s2 == REQ_ERROR) |
| 1371 | return BLKIF_RSP_ERROR; |
| 1372 | else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP) |
| 1373 | return BLKIF_RSP_EOPNOTSUPP; |
| 1374 | return BLKIF_RSP_OKAY; |
| 1375 | } |
| 1376 | |
| 1377 | /* |
| 1378 | * Return values: |
| 1379 | * 1 response processed. |
| 1380 | * 0 missing further responses. |
| 1381 | * -1 error while processing. |
| 1382 | */ |
| 1383 | static int blkif_completion(unsigned long *id, |
| 1384 | struct blkfront_ring_info *rinfo, |
| 1385 | struct blkif_response *bret) |
| 1386 | { |
| 1387 | int i = 0; |
| 1388 | struct scatterlist *sg; |
| 1389 | int num_sg, num_grant; |
| 1390 | struct blkfront_info *info = rinfo->dev_info; |
| 1391 | struct blk_shadow *s = &rinfo->shadow[*id]; |
| 1392 | struct copy_from_grant data = { |
| 1393 | .grant_idx = 0, |
| 1394 | }; |
| 1395 | |
| 1396 | num_grant = s->req.operation == BLKIF_OP_INDIRECT ? |
| 1397 | s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; |
| 1398 | |
| 1399 | /* The I/O request may be split in two. */ |
| 1400 | if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) { |
| 1401 | struct blk_shadow *s2 = &rinfo->shadow[s->associated_id]; |
| 1402 | |
| 1403 | /* Keep the status of the current response in shadow. */ |
| 1404 | s->status = blkif_rsp_to_req_status(bret->status); |
| 1405 | |
| 1406 | /* Wait the second response if not yet here. */ |
| 1407 | if (s2->status < REQ_DONE) |
| 1408 | return 0; |
| 1409 | |
| 1410 | bret->status = blkif_get_final_status(s->status, |
| 1411 | s2->status); |
| 1412 | |
| 1413 | /* |
| 1414 | * All the grants is stored in the first shadow in order |
| 1415 | * to make the completion code simpler. |
| 1416 | */ |
| 1417 | num_grant += s2->req.u.rw.nr_segments; |
| 1418 | |
| 1419 | /* |
| 1420 | * The two responses may not come in order. Only the |
| 1421 | * first request will store the scatter-gather list. |
| 1422 | */ |
| 1423 | if (s2->num_sg != 0) { |
| 1424 | /* Update "id" with the ID of the first response. */ |
| 1425 | *id = s->associated_id; |
| 1426 | s = s2; |
| 1427 | } |
| 1428 | |
| 1429 | /* |
| 1430 | * We don't need anymore the second request, so recycling |
| 1431 | * it now. |
| 1432 | */ |
| 1433 | if (add_id_to_freelist(rinfo, s->associated_id)) |
| 1434 | WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n", |
| 1435 | info->gd->disk_name, s->associated_id); |
| 1436 | } |
| 1437 | |
| 1438 | data.s = s; |
| 1439 | num_sg = s->num_sg; |
| 1440 | |
| 1441 | if (bret->operation == BLKIF_OP_READ && info->bounce) { |
| 1442 | for_each_sg(s->sg, sg, num_sg, i) { |
| 1443 | BUG_ON(sg->offset + sg->length > PAGE_SIZE); |
| 1444 | |
| 1445 | data.bvec_offset = sg->offset; |
| 1446 | data.bvec_data = kmap_atomic(sg_page(sg)); |
| 1447 | |
| 1448 | gnttab_foreach_grant_in_range(sg_page(sg), |
| 1449 | sg->offset, |
| 1450 | sg->length, |
| 1451 | blkif_copy_from_grant, |
| 1452 | &data); |
| 1453 | |
| 1454 | kunmap_atomic(data.bvec_data); |
| 1455 | } |
| 1456 | } |
| 1457 | /* Add the persistent grant into the list of free grants */ |
| 1458 | for (i = 0; i < num_grant; i++) { |
| 1459 | if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) { |
| 1460 | /* |
| 1461 | * If the grant is still mapped by the backend (the |
| 1462 | * backend has chosen to make this grant persistent) |
| 1463 | * we add it at the head of the list, so it will be |
| 1464 | * reused first. |
| 1465 | */ |
| 1466 | if (!info->feature_persistent) { |
| 1467 | pr_alert("backed has not unmapped grant: %u\n", |
| 1468 | s->grants_used[i]->gref); |
| 1469 | return -1; |
| 1470 | } |
| 1471 | list_add(&s->grants_used[i]->node, &rinfo->grants); |
| 1472 | rinfo->persistent_gnts_c++; |
| 1473 | } else { |
| 1474 | /* |
| 1475 | * If the grant is not mapped by the backend we add it |
| 1476 | * to the tail of the list, so it will not be picked |
| 1477 | * again unless we run out of persistent grants. |
| 1478 | */ |
| 1479 | s->grants_used[i]->gref = INVALID_GRANT_REF; |
| 1480 | list_add_tail(&s->grants_used[i]->node, &rinfo->grants); |
| 1481 | } |
| 1482 | } |
| 1483 | if (s->req.operation == BLKIF_OP_INDIRECT) { |
| 1484 | for (i = 0; i < INDIRECT_GREFS(num_grant); i++) { |
| 1485 | if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) { |
| 1486 | if (!info->feature_persistent) { |
| 1487 | pr_alert("backed has not unmapped grant: %u\n", |
| 1488 | s->indirect_grants[i]->gref); |
| 1489 | return -1; |
| 1490 | } |
| 1491 | list_add(&s->indirect_grants[i]->node, &rinfo->grants); |
| 1492 | rinfo->persistent_gnts_c++; |
| 1493 | } else { |
| 1494 | struct page *indirect_page; |
| 1495 | |
| 1496 | /* |
| 1497 | * Add the used indirect page back to the list of |
| 1498 | * available pages for indirect grefs. |
| 1499 | */ |
| 1500 | if (!info->bounce) { |
| 1501 | indirect_page = s->indirect_grants[i]->page; |
| 1502 | list_add(&indirect_page->lru, &rinfo->indirect_pages); |
| 1503 | } |
| 1504 | s->indirect_grants[i]->gref = INVALID_GRANT_REF; |
| 1505 | list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants); |
| 1506 | } |
| 1507 | } |
| 1508 | } |
| 1509 | |
| 1510 | return 1; |
| 1511 | } |
| 1512 | |
| 1513 | static irqreturn_t blkif_interrupt(int irq, void *dev_id) |
| 1514 | { |
| 1515 | struct request *req; |
| 1516 | struct blkif_response bret; |
| 1517 | RING_IDX i, rp; |
| 1518 | unsigned long flags; |
| 1519 | struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id; |
| 1520 | struct blkfront_info *info = rinfo->dev_info; |
| 1521 | unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; |
| 1522 | |
| 1523 | if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { |
| 1524 | xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS); |
| 1525 | return IRQ_HANDLED; |
| 1526 | } |
| 1527 | |
| 1528 | spin_lock_irqsave(&rinfo->ring_lock, flags); |
| 1529 | again: |
| 1530 | rp = READ_ONCE(rinfo->ring.sring->rsp_prod); |
| 1531 | virt_rmb(); /* Ensure we see queued responses up to 'rp'. */ |
| 1532 | if (RING_RESPONSE_PROD_OVERFLOW(&rinfo->ring, rp)) { |
| 1533 | pr_alert("%s: illegal number of responses %u\n", |
| 1534 | info->gd->disk_name, rp - rinfo->ring.rsp_cons); |
| 1535 | goto err; |
| 1536 | } |
| 1537 | |
| 1538 | for (i = rinfo->ring.rsp_cons; i != rp; i++) { |
| 1539 | unsigned long id; |
| 1540 | unsigned int op; |
| 1541 | |
| 1542 | eoiflag = 0; |
| 1543 | |
| 1544 | RING_COPY_RESPONSE(&rinfo->ring, i, &bret); |
| 1545 | id = bret.id; |
| 1546 | |
| 1547 | /* |
| 1548 | * The backend has messed up and given us an id that we would |
| 1549 | * never have given to it (we stamp it up to BLK_RING_SIZE - |
| 1550 | * look in get_id_from_freelist. |
| 1551 | */ |
| 1552 | if (id >= BLK_RING_SIZE(info)) { |
| 1553 | pr_alert("%s: response has incorrect id (%ld)\n", |
| 1554 | info->gd->disk_name, id); |
| 1555 | goto err; |
| 1556 | } |
| 1557 | if (rinfo->shadow[id].status != REQ_WAITING) { |
| 1558 | pr_alert("%s: response references no pending request\n", |
| 1559 | info->gd->disk_name); |
| 1560 | goto err; |
| 1561 | } |
| 1562 | |
| 1563 | rinfo->shadow[id].status = REQ_PROCESSING; |
| 1564 | req = rinfo->shadow[id].request; |
| 1565 | |
| 1566 | op = rinfo->shadow[id].req.operation; |
| 1567 | if (op == BLKIF_OP_INDIRECT) |
| 1568 | op = rinfo->shadow[id].req.u.indirect.indirect_op; |
| 1569 | if (bret.operation != op) { |
| 1570 | pr_alert("%s: response has wrong operation (%u instead of %u)\n", |
| 1571 | info->gd->disk_name, bret.operation, op); |
| 1572 | goto err; |
| 1573 | } |
| 1574 | |
| 1575 | if (bret.operation != BLKIF_OP_DISCARD) { |
| 1576 | int ret; |
| 1577 | |
| 1578 | /* |
| 1579 | * We may need to wait for an extra response if the |
| 1580 | * I/O request is split in 2 |
| 1581 | */ |
| 1582 | ret = blkif_completion(&id, rinfo, &bret); |
| 1583 | if (!ret) |
| 1584 | continue; |
| 1585 | if (unlikely(ret < 0)) |
| 1586 | goto err; |
| 1587 | } |
| 1588 | |
| 1589 | if (add_id_to_freelist(rinfo, id)) { |
| 1590 | WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n", |
| 1591 | info->gd->disk_name, op_name(bret.operation), id); |
| 1592 | continue; |
| 1593 | } |
| 1594 | |
| 1595 | if (bret.status == BLKIF_RSP_OKAY) |
| 1596 | blkif_req(req)->error = BLK_STS_OK; |
| 1597 | else |
| 1598 | blkif_req(req)->error = BLK_STS_IOERR; |
| 1599 | |
| 1600 | switch (bret.operation) { |
| 1601 | case BLKIF_OP_DISCARD: |
| 1602 | if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) { |
| 1603 | struct request_queue *rq = info->rq; |
| 1604 | |
| 1605 | pr_warn_ratelimited("blkfront: %s: %s op failed\n", |
| 1606 | info->gd->disk_name, op_name(bret.operation)); |
| 1607 | blkif_req(req)->error = BLK_STS_NOTSUPP; |
| 1608 | info->feature_discard = 0; |
| 1609 | info->feature_secdiscard = 0; |
| 1610 | blk_queue_max_discard_sectors(rq, 0); |
| 1611 | blk_queue_max_secure_erase_sectors(rq, 0); |
| 1612 | } |
| 1613 | break; |
| 1614 | case BLKIF_OP_FLUSH_DISKCACHE: |
| 1615 | case BLKIF_OP_WRITE_BARRIER: |
| 1616 | if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) { |
| 1617 | pr_warn_ratelimited("blkfront: %s: %s op failed\n", |
| 1618 | info->gd->disk_name, op_name(bret.operation)); |
| 1619 | blkif_req(req)->error = BLK_STS_NOTSUPP; |
| 1620 | } |
| 1621 | if (unlikely(bret.status == BLKIF_RSP_ERROR && |
| 1622 | rinfo->shadow[id].req.u.rw.nr_segments == 0)) { |
| 1623 | pr_warn_ratelimited("blkfront: %s: empty %s op failed\n", |
| 1624 | info->gd->disk_name, op_name(bret.operation)); |
| 1625 | blkif_req(req)->error = BLK_STS_NOTSUPP; |
| 1626 | } |
| 1627 | if (unlikely(blkif_req(req)->error)) { |
| 1628 | if (blkif_req(req)->error == BLK_STS_NOTSUPP) |
| 1629 | blkif_req(req)->error = BLK_STS_OK; |
| 1630 | info->feature_fua = 0; |
| 1631 | info->feature_flush = 0; |
| 1632 | xlvbd_flush(info); |
| 1633 | } |
| 1634 | fallthrough; |
| 1635 | case BLKIF_OP_READ: |
| 1636 | case BLKIF_OP_WRITE: |
| 1637 | if (unlikely(bret.status != BLKIF_RSP_OKAY)) |
| 1638 | dev_dbg_ratelimited(&info->xbdev->dev, |
| 1639 | "Bad return from blkdev data request: %#x\n", |
| 1640 | bret.status); |
| 1641 | |
| 1642 | break; |
| 1643 | default: |
| 1644 | BUG(); |
| 1645 | } |
| 1646 | |
| 1647 | if (likely(!blk_should_fake_timeout(req->q))) |
| 1648 | blk_mq_complete_request(req); |
| 1649 | } |
| 1650 | |
| 1651 | rinfo->ring.rsp_cons = i; |
| 1652 | |
| 1653 | if (i != rinfo->ring.req_prod_pvt) { |
| 1654 | int more_to_do; |
| 1655 | RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do); |
| 1656 | if (more_to_do) |
| 1657 | goto again; |
| 1658 | } else |
| 1659 | rinfo->ring.sring->rsp_event = i + 1; |
| 1660 | |
| 1661 | kick_pending_request_queues_locked(rinfo); |
| 1662 | |
| 1663 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 1664 | |
| 1665 | xen_irq_lateeoi(irq, eoiflag); |
| 1666 | |
| 1667 | return IRQ_HANDLED; |
| 1668 | |
| 1669 | err: |
| 1670 | info->connected = BLKIF_STATE_ERROR; |
| 1671 | |
| 1672 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 1673 | |
| 1674 | /* No EOI in order to avoid further interrupts. */ |
| 1675 | |
| 1676 | pr_alert("%s disabled for further use\n", info->gd->disk_name); |
| 1677 | return IRQ_HANDLED; |
| 1678 | } |
| 1679 | |
| 1680 | |
| 1681 | static int setup_blkring(struct xenbus_device *dev, |
| 1682 | struct blkfront_ring_info *rinfo) |
| 1683 | { |
| 1684 | struct blkif_sring *sring; |
| 1685 | int err; |
| 1686 | struct blkfront_info *info = rinfo->dev_info; |
| 1687 | unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; |
| 1688 | |
| 1689 | err = xenbus_setup_ring(dev, GFP_NOIO, (void **)&sring, |
| 1690 | info->nr_ring_pages, rinfo->ring_ref); |
| 1691 | if (err) |
| 1692 | goto fail; |
| 1693 | |
| 1694 | XEN_FRONT_RING_INIT(&rinfo->ring, sring, ring_size); |
| 1695 | |
| 1696 | err = xenbus_alloc_evtchn(dev, &rinfo->evtchn); |
| 1697 | if (err) |
| 1698 | goto fail; |
| 1699 | |
| 1700 | err = bind_evtchn_to_irqhandler_lateeoi(rinfo->evtchn, blkif_interrupt, |
| 1701 | 0, "blkif", rinfo); |
| 1702 | if (err <= 0) { |
| 1703 | xenbus_dev_fatal(dev, err, |
| 1704 | "bind_evtchn_to_irqhandler failed"); |
| 1705 | goto fail; |
| 1706 | } |
| 1707 | rinfo->irq = err; |
| 1708 | |
| 1709 | return 0; |
| 1710 | fail: |
| 1711 | blkif_free(info, 0); |
| 1712 | return err; |
| 1713 | } |
| 1714 | |
| 1715 | /* |
| 1716 | * Write out per-ring/queue nodes including ring-ref and event-channel, and each |
| 1717 | * ring buffer may have multi pages depending on ->nr_ring_pages. |
| 1718 | */ |
| 1719 | static int write_per_ring_nodes(struct xenbus_transaction xbt, |
| 1720 | struct blkfront_ring_info *rinfo, const char *dir) |
| 1721 | { |
| 1722 | int err; |
| 1723 | unsigned int i; |
| 1724 | const char *message = NULL; |
| 1725 | struct blkfront_info *info = rinfo->dev_info; |
| 1726 | |
| 1727 | if (info->nr_ring_pages == 1) { |
| 1728 | err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]); |
| 1729 | if (err) { |
| 1730 | message = "writing ring-ref"; |
| 1731 | goto abort_transaction; |
| 1732 | } |
| 1733 | } else { |
| 1734 | for (i = 0; i < info->nr_ring_pages; i++) { |
| 1735 | char ring_ref_name[RINGREF_NAME_LEN]; |
| 1736 | |
| 1737 | snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); |
| 1738 | err = xenbus_printf(xbt, dir, ring_ref_name, |
| 1739 | "%u", rinfo->ring_ref[i]); |
| 1740 | if (err) { |
| 1741 | message = "writing ring-ref"; |
| 1742 | goto abort_transaction; |
| 1743 | } |
| 1744 | } |
| 1745 | } |
| 1746 | |
| 1747 | err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn); |
| 1748 | if (err) { |
| 1749 | message = "writing event-channel"; |
| 1750 | goto abort_transaction; |
| 1751 | } |
| 1752 | |
| 1753 | return 0; |
| 1754 | |
| 1755 | abort_transaction: |
| 1756 | xenbus_transaction_end(xbt, 1); |
| 1757 | if (message) |
| 1758 | xenbus_dev_fatal(info->xbdev, err, "%s", message); |
| 1759 | |
| 1760 | return err; |
| 1761 | } |
| 1762 | |
| 1763 | /* Enable the persistent grants feature. */ |
| 1764 | static bool feature_persistent = true; |
| 1765 | module_param(feature_persistent, bool, 0644); |
| 1766 | MODULE_PARM_DESC(feature_persistent, |
| 1767 | "Enables the persistent grants feature"); |
| 1768 | |
| 1769 | /* Common code used when first setting up, and when resuming. */ |
| 1770 | static int talk_to_blkback(struct xenbus_device *dev, |
| 1771 | struct blkfront_info *info) |
| 1772 | { |
| 1773 | const char *message = NULL; |
| 1774 | struct xenbus_transaction xbt; |
| 1775 | int err; |
| 1776 | unsigned int i, max_page_order; |
| 1777 | unsigned int ring_page_order; |
| 1778 | struct blkfront_ring_info *rinfo; |
| 1779 | |
| 1780 | if (!info) |
| 1781 | return -ENODEV; |
| 1782 | |
| 1783 | /* Check if backend is trusted. */ |
| 1784 | info->bounce = !xen_blkif_trusted || |
| 1785 | !xenbus_read_unsigned(dev->nodename, "trusted", 1); |
| 1786 | |
| 1787 | max_page_order = xenbus_read_unsigned(info->xbdev->otherend, |
| 1788 | "max-ring-page-order", 0); |
| 1789 | ring_page_order = min(xen_blkif_max_ring_order, max_page_order); |
| 1790 | info->nr_ring_pages = 1 << ring_page_order; |
| 1791 | |
| 1792 | err = negotiate_mq(info); |
| 1793 | if (err) |
| 1794 | goto destroy_blkring; |
| 1795 | |
| 1796 | for_each_rinfo(info, rinfo, i) { |
| 1797 | /* Create shared ring, alloc event channel. */ |
| 1798 | err = setup_blkring(dev, rinfo); |
| 1799 | if (err) |
| 1800 | goto destroy_blkring; |
| 1801 | } |
| 1802 | |
| 1803 | again: |
| 1804 | err = xenbus_transaction_start(&xbt); |
| 1805 | if (err) { |
| 1806 | xenbus_dev_fatal(dev, err, "starting transaction"); |
| 1807 | goto destroy_blkring; |
| 1808 | } |
| 1809 | |
| 1810 | if (info->nr_ring_pages > 1) { |
| 1811 | err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u", |
| 1812 | ring_page_order); |
| 1813 | if (err) { |
| 1814 | message = "writing ring-page-order"; |
| 1815 | goto abort_transaction; |
| 1816 | } |
| 1817 | } |
| 1818 | |
| 1819 | /* We already got the number of queues/rings in _probe */ |
| 1820 | if (info->nr_rings == 1) { |
| 1821 | err = write_per_ring_nodes(xbt, info->rinfo, dev->nodename); |
| 1822 | if (err) |
| 1823 | goto destroy_blkring; |
| 1824 | } else { |
| 1825 | char *path; |
| 1826 | size_t pathsize; |
| 1827 | |
| 1828 | err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u", |
| 1829 | info->nr_rings); |
| 1830 | if (err) { |
| 1831 | message = "writing multi-queue-num-queues"; |
| 1832 | goto abort_transaction; |
| 1833 | } |
| 1834 | |
| 1835 | pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN; |
| 1836 | path = kmalloc(pathsize, GFP_KERNEL); |
| 1837 | if (!path) { |
| 1838 | err = -ENOMEM; |
| 1839 | message = "ENOMEM while writing ring references"; |
| 1840 | goto abort_transaction; |
| 1841 | } |
| 1842 | |
| 1843 | for_each_rinfo(info, rinfo, i) { |
| 1844 | memset(path, 0, pathsize); |
| 1845 | snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i); |
| 1846 | err = write_per_ring_nodes(xbt, rinfo, path); |
| 1847 | if (err) { |
| 1848 | kfree(path); |
| 1849 | goto destroy_blkring; |
| 1850 | } |
| 1851 | } |
| 1852 | kfree(path); |
| 1853 | } |
| 1854 | err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", |
| 1855 | XEN_IO_PROTO_ABI_NATIVE); |
| 1856 | if (err) { |
| 1857 | message = "writing protocol"; |
| 1858 | goto abort_transaction; |
| 1859 | } |
| 1860 | info->feature_persistent_parm = feature_persistent; |
| 1861 | err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", |
| 1862 | info->feature_persistent_parm); |
| 1863 | if (err) |
| 1864 | dev_warn(&dev->dev, |
| 1865 | "writing persistent grants feature to xenbus"); |
| 1866 | |
| 1867 | err = xenbus_transaction_end(xbt, 0); |
| 1868 | if (err) { |
| 1869 | if (err == -EAGAIN) |
| 1870 | goto again; |
| 1871 | xenbus_dev_fatal(dev, err, "completing transaction"); |
| 1872 | goto destroy_blkring; |
| 1873 | } |
| 1874 | |
| 1875 | for_each_rinfo(info, rinfo, i) { |
| 1876 | unsigned int j; |
| 1877 | |
| 1878 | for (j = 0; j < BLK_RING_SIZE(info); j++) |
| 1879 | rinfo->shadow[j].req.u.rw.id = j + 1; |
| 1880 | rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff; |
| 1881 | } |
| 1882 | xenbus_switch_state(dev, XenbusStateInitialised); |
| 1883 | |
| 1884 | return 0; |
| 1885 | |
| 1886 | abort_transaction: |
| 1887 | xenbus_transaction_end(xbt, 1); |
| 1888 | if (message) |
| 1889 | xenbus_dev_fatal(dev, err, "%s", message); |
| 1890 | destroy_blkring: |
| 1891 | blkif_free(info, 0); |
| 1892 | return err; |
| 1893 | } |
| 1894 | |
| 1895 | static int negotiate_mq(struct blkfront_info *info) |
| 1896 | { |
| 1897 | unsigned int backend_max_queues; |
| 1898 | unsigned int i; |
| 1899 | struct blkfront_ring_info *rinfo; |
| 1900 | |
| 1901 | BUG_ON(info->nr_rings); |
| 1902 | |
| 1903 | /* Check if backend supports multiple queues. */ |
| 1904 | backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend, |
| 1905 | "multi-queue-max-queues", 1); |
| 1906 | info->nr_rings = min(backend_max_queues, xen_blkif_max_queues); |
| 1907 | /* We need at least one ring. */ |
| 1908 | if (!info->nr_rings) |
| 1909 | info->nr_rings = 1; |
| 1910 | |
| 1911 | info->rinfo_size = struct_size(info->rinfo, shadow, |
| 1912 | BLK_RING_SIZE(info)); |
| 1913 | info->rinfo = kvcalloc(info->nr_rings, info->rinfo_size, GFP_KERNEL); |
| 1914 | if (!info->rinfo) { |
| 1915 | xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); |
| 1916 | info->nr_rings = 0; |
| 1917 | return -ENOMEM; |
| 1918 | } |
| 1919 | |
| 1920 | for_each_rinfo(info, rinfo, i) { |
| 1921 | INIT_LIST_HEAD(&rinfo->indirect_pages); |
| 1922 | INIT_LIST_HEAD(&rinfo->grants); |
| 1923 | rinfo->dev_info = info; |
| 1924 | INIT_WORK(&rinfo->work, blkif_restart_queue); |
| 1925 | spin_lock_init(&rinfo->ring_lock); |
| 1926 | } |
| 1927 | return 0; |
| 1928 | } |
| 1929 | |
| 1930 | /* |
| 1931 | * Entry point to this code when a new device is created. Allocate the basic |
| 1932 | * structures and the ring buffer for communication with the backend, and |
| 1933 | * inform the backend of the appropriate details for those. Switch to |
| 1934 | * Initialised state. |
| 1935 | */ |
| 1936 | static int blkfront_probe(struct xenbus_device *dev, |
| 1937 | const struct xenbus_device_id *id) |
| 1938 | { |
| 1939 | int err, vdevice; |
| 1940 | struct blkfront_info *info; |
| 1941 | |
| 1942 | /* FIXME: Use dynamic device id if this is not set. */ |
| 1943 | err = xenbus_scanf(XBT_NIL, dev->nodename, |
| 1944 | "virtual-device", "%i", &vdevice); |
| 1945 | if (err != 1) { |
| 1946 | /* go looking in the extended area instead */ |
| 1947 | err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", |
| 1948 | "%i", &vdevice); |
| 1949 | if (err != 1) { |
| 1950 | xenbus_dev_fatal(dev, err, "reading virtual-device"); |
| 1951 | return err; |
| 1952 | } |
| 1953 | } |
| 1954 | |
| 1955 | if (xen_hvm_domain()) { |
| 1956 | char *type; |
| 1957 | int len; |
| 1958 | /* no unplug has been done: do not hook devices != xen vbds */ |
| 1959 | if (xen_has_pv_and_legacy_disk_devices()) { |
| 1960 | int major; |
| 1961 | |
| 1962 | if (!VDEV_IS_EXTENDED(vdevice)) |
| 1963 | major = BLKIF_MAJOR(vdevice); |
| 1964 | else |
| 1965 | major = XENVBD_MAJOR; |
| 1966 | |
| 1967 | if (major != XENVBD_MAJOR) { |
| 1968 | printk(KERN_INFO |
| 1969 | "%s: HVM does not support vbd %d as xen block device\n", |
| 1970 | __func__, vdevice); |
| 1971 | return -ENODEV; |
| 1972 | } |
| 1973 | } |
| 1974 | /* do not create a PV cdrom device if we are an HVM guest */ |
| 1975 | type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); |
| 1976 | if (IS_ERR(type)) |
| 1977 | return -ENODEV; |
| 1978 | if (strncmp(type, "cdrom", 5) == 0) { |
| 1979 | kfree(type); |
| 1980 | return -ENODEV; |
| 1981 | } |
| 1982 | kfree(type); |
| 1983 | } |
| 1984 | info = kzalloc(sizeof(*info), GFP_KERNEL); |
| 1985 | if (!info) { |
| 1986 | xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); |
| 1987 | return -ENOMEM; |
| 1988 | } |
| 1989 | |
| 1990 | info->xbdev = dev; |
| 1991 | |
| 1992 | mutex_init(&info->mutex); |
| 1993 | info->vdevice = vdevice; |
| 1994 | info->connected = BLKIF_STATE_DISCONNECTED; |
| 1995 | |
| 1996 | /* Front end dir is a number, which is used as the id. */ |
| 1997 | info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); |
| 1998 | dev_set_drvdata(&dev->dev, info); |
| 1999 | |
| 2000 | mutex_lock(&blkfront_mutex); |
| 2001 | list_add(&info->info_list, &info_list); |
| 2002 | mutex_unlock(&blkfront_mutex); |
| 2003 | |
| 2004 | return 0; |
| 2005 | } |
| 2006 | |
| 2007 | static int blkif_recover(struct blkfront_info *info) |
| 2008 | { |
| 2009 | unsigned int r_index; |
| 2010 | struct request *req, *n; |
| 2011 | int rc; |
| 2012 | struct bio *bio; |
| 2013 | unsigned int segs; |
| 2014 | struct blkfront_ring_info *rinfo; |
| 2015 | |
| 2016 | blkfront_gather_backend_features(info); |
| 2017 | /* Reset limits changed by blk_mq_update_nr_hw_queues(). */ |
| 2018 | blkif_set_queue_limits(info); |
| 2019 | segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 2020 | blk_queue_max_segments(info->rq, segs / GRANTS_PER_PSEG); |
| 2021 | |
| 2022 | for_each_rinfo(info, rinfo, r_index) { |
| 2023 | rc = blkfront_setup_indirect(rinfo); |
| 2024 | if (rc) |
| 2025 | return rc; |
| 2026 | } |
| 2027 | xenbus_switch_state(info->xbdev, XenbusStateConnected); |
| 2028 | |
| 2029 | /* Now safe for us to use the shared ring */ |
| 2030 | info->connected = BLKIF_STATE_CONNECTED; |
| 2031 | |
| 2032 | for_each_rinfo(info, rinfo, r_index) { |
| 2033 | /* Kick any other new requests queued since we resumed */ |
| 2034 | kick_pending_request_queues(rinfo); |
| 2035 | } |
| 2036 | |
| 2037 | list_for_each_entry_safe(req, n, &info->requests, queuelist) { |
| 2038 | /* Requeue pending requests (flush or discard) */ |
| 2039 | list_del_init(&req->queuelist); |
| 2040 | BUG_ON(req->nr_phys_segments > segs); |
| 2041 | blk_mq_requeue_request(req, false); |
| 2042 | } |
| 2043 | blk_mq_start_stopped_hw_queues(info->rq, true); |
| 2044 | blk_mq_kick_requeue_list(info->rq); |
| 2045 | |
| 2046 | while ((bio = bio_list_pop(&info->bio_list)) != NULL) { |
| 2047 | /* Traverse the list of pending bios and re-queue them */ |
| 2048 | submit_bio(bio); |
| 2049 | } |
| 2050 | |
| 2051 | return 0; |
| 2052 | } |
| 2053 | |
| 2054 | /* |
| 2055 | * We are reconnecting to the backend, due to a suspend/resume, or a backend |
| 2056 | * driver restart. We tear down our blkif structure and recreate it, but |
| 2057 | * leave the device-layer structures intact so that this is transparent to the |
| 2058 | * rest of the kernel. |
| 2059 | */ |
| 2060 | static int blkfront_resume(struct xenbus_device *dev) |
| 2061 | { |
| 2062 | struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
| 2063 | int err = 0; |
| 2064 | unsigned int i, j; |
| 2065 | struct blkfront_ring_info *rinfo; |
| 2066 | |
| 2067 | dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); |
| 2068 | |
| 2069 | bio_list_init(&info->bio_list); |
| 2070 | INIT_LIST_HEAD(&info->requests); |
| 2071 | for_each_rinfo(info, rinfo, i) { |
| 2072 | struct bio_list merge_bio; |
| 2073 | struct blk_shadow *shadow = rinfo->shadow; |
| 2074 | |
| 2075 | for (j = 0; j < BLK_RING_SIZE(info); j++) { |
| 2076 | /* Not in use? */ |
| 2077 | if (!shadow[j].request) |
| 2078 | continue; |
| 2079 | |
| 2080 | /* |
| 2081 | * Get the bios in the request so we can re-queue them. |
| 2082 | */ |
| 2083 | if (req_op(shadow[j].request) == REQ_OP_FLUSH || |
| 2084 | req_op(shadow[j].request) == REQ_OP_DISCARD || |
| 2085 | req_op(shadow[j].request) == REQ_OP_SECURE_ERASE || |
| 2086 | shadow[j].request->cmd_flags & REQ_FUA) { |
| 2087 | /* |
| 2088 | * Flush operations don't contain bios, so |
| 2089 | * we need to requeue the whole request |
| 2090 | * |
| 2091 | * XXX: but this doesn't make any sense for a |
| 2092 | * write with the FUA flag set.. |
| 2093 | */ |
| 2094 | list_add(&shadow[j].request->queuelist, &info->requests); |
| 2095 | continue; |
| 2096 | } |
| 2097 | merge_bio.head = shadow[j].request->bio; |
| 2098 | merge_bio.tail = shadow[j].request->biotail; |
| 2099 | bio_list_merge(&info->bio_list, &merge_bio); |
| 2100 | shadow[j].request->bio = NULL; |
| 2101 | blk_mq_end_request(shadow[j].request, BLK_STS_OK); |
| 2102 | } |
| 2103 | } |
| 2104 | |
| 2105 | blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); |
| 2106 | |
| 2107 | err = talk_to_blkback(dev, info); |
| 2108 | if (!err) |
| 2109 | blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings); |
| 2110 | |
| 2111 | /* |
| 2112 | * We have to wait for the backend to switch to |
| 2113 | * connected state, since we want to read which |
| 2114 | * features it supports. |
| 2115 | */ |
| 2116 | |
| 2117 | return err; |
| 2118 | } |
| 2119 | |
| 2120 | static void blkfront_closing(struct blkfront_info *info) |
| 2121 | { |
| 2122 | struct xenbus_device *xbdev = info->xbdev; |
| 2123 | struct blkfront_ring_info *rinfo; |
| 2124 | unsigned int i; |
| 2125 | |
| 2126 | if (xbdev->state == XenbusStateClosing) |
| 2127 | return; |
| 2128 | |
| 2129 | /* No more blkif_request(). */ |
| 2130 | if (info->rq && info->gd) { |
| 2131 | blk_mq_stop_hw_queues(info->rq); |
| 2132 | blk_mark_disk_dead(info->gd); |
| 2133 | } |
| 2134 | |
| 2135 | for_each_rinfo(info, rinfo, i) { |
| 2136 | /* No more gnttab callback work. */ |
| 2137 | gnttab_cancel_free_callback(&rinfo->callback); |
| 2138 | |
| 2139 | /* Flush gnttab callback work. Must be done with no locks held. */ |
| 2140 | flush_work(&rinfo->work); |
| 2141 | } |
| 2142 | |
| 2143 | xenbus_frontend_closed(xbdev); |
| 2144 | } |
| 2145 | |
| 2146 | static void blkfront_setup_discard(struct blkfront_info *info) |
| 2147 | { |
| 2148 | info->feature_discard = 1; |
| 2149 | info->discard_granularity = xenbus_read_unsigned(info->xbdev->otherend, |
| 2150 | "discard-granularity", |
| 2151 | 0); |
| 2152 | info->discard_alignment = xenbus_read_unsigned(info->xbdev->otherend, |
| 2153 | "discard-alignment", 0); |
| 2154 | info->feature_secdiscard = |
| 2155 | !!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure", |
| 2156 | 0); |
| 2157 | } |
| 2158 | |
| 2159 | static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) |
| 2160 | { |
| 2161 | unsigned int psegs, grants, memflags; |
| 2162 | int err, i; |
| 2163 | struct blkfront_info *info = rinfo->dev_info; |
| 2164 | |
| 2165 | memflags = memalloc_noio_save(); |
| 2166 | |
| 2167 | if (info->max_indirect_segments == 0) { |
| 2168 | if (!HAS_EXTRA_REQ) |
| 2169 | grants = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 2170 | else { |
| 2171 | /* |
| 2172 | * When an extra req is required, the maximum |
| 2173 | * grants supported is related to the size of the |
| 2174 | * Linux block segment. |
| 2175 | */ |
| 2176 | grants = GRANTS_PER_PSEG; |
| 2177 | } |
| 2178 | } |
| 2179 | else |
| 2180 | grants = info->max_indirect_segments; |
| 2181 | psegs = DIV_ROUND_UP(grants, GRANTS_PER_PSEG); |
| 2182 | |
| 2183 | err = fill_grant_buffer(rinfo, |
| 2184 | (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info)); |
| 2185 | if (err) |
| 2186 | goto out_of_memory; |
| 2187 | |
| 2188 | if (!info->bounce && info->max_indirect_segments) { |
| 2189 | /* |
| 2190 | * We are using indirect descriptors but don't have a bounce |
| 2191 | * buffer, we need to allocate a set of pages that can be |
| 2192 | * used for mapping indirect grefs |
| 2193 | */ |
| 2194 | int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); |
| 2195 | |
| 2196 | BUG_ON(!list_empty(&rinfo->indirect_pages)); |
| 2197 | for (i = 0; i < num; i++) { |
| 2198 | struct page *indirect_page = alloc_page(GFP_KERNEL | |
| 2199 | __GFP_ZERO); |
| 2200 | if (!indirect_page) |
| 2201 | goto out_of_memory; |
| 2202 | list_add(&indirect_page->lru, &rinfo->indirect_pages); |
| 2203 | } |
| 2204 | } |
| 2205 | |
| 2206 | for (i = 0; i < BLK_RING_SIZE(info); i++) { |
| 2207 | rinfo->shadow[i].grants_used = |
| 2208 | kvcalloc(grants, |
| 2209 | sizeof(rinfo->shadow[i].grants_used[0]), |
| 2210 | GFP_KERNEL); |
| 2211 | rinfo->shadow[i].sg = kvcalloc(psegs, |
| 2212 | sizeof(rinfo->shadow[i].sg[0]), |
| 2213 | GFP_KERNEL); |
| 2214 | if (info->max_indirect_segments) |
| 2215 | rinfo->shadow[i].indirect_grants = |
| 2216 | kvcalloc(INDIRECT_GREFS(grants), |
| 2217 | sizeof(rinfo->shadow[i].indirect_grants[0]), |
| 2218 | GFP_KERNEL); |
| 2219 | if ((rinfo->shadow[i].grants_used == NULL) || |
| 2220 | (rinfo->shadow[i].sg == NULL) || |
| 2221 | (info->max_indirect_segments && |
| 2222 | (rinfo->shadow[i].indirect_grants == NULL))) |
| 2223 | goto out_of_memory; |
| 2224 | sg_init_table(rinfo->shadow[i].sg, psegs); |
| 2225 | } |
| 2226 | |
| 2227 | memalloc_noio_restore(memflags); |
| 2228 | |
| 2229 | return 0; |
| 2230 | |
| 2231 | out_of_memory: |
| 2232 | for (i = 0; i < BLK_RING_SIZE(info); i++) { |
| 2233 | kvfree(rinfo->shadow[i].grants_used); |
| 2234 | rinfo->shadow[i].grants_used = NULL; |
| 2235 | kvfree(rinfo->shadow[i].sg); |
| 2236 | rinfo->shadow[i].sg = NULL; |
| 2237 | kvfree(rinfo->shadow[i].indirect_grants); |
| 2238 | rinfo->shadow[i].indirect_grants = NULL; |
| 2239 | } |
| 2240 | if (!list_empty(&rinfo->indirect_pages)) { |
| 2241 | struct page *indirect_page, *n; |
| 2242 | list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { |
| 2243 | list_del(&indirect_page->lru); |
| 2244 | __free_page(indirect_page); |
| 2245 | } |
| 2246 | } |
| 2247 | |
| 2248 | memalloc_noio_restore(memflags); |
| 2249 | |
| 2250 | return -ENOMEM; |
| 2251 | } |
| 2252 | |
| 2253 | /* |
| 2254 | * Gather all backend feature-* |
| 2255 | */ |
| 2256 | static void blkfront_gather_backend_features(struct blkfront_info *info) |
| 2257 | { |
| 2258 | unsigned int indirect_segments; |
| 2259 | |
| 2260 | info->feature_flush = 0; |
| 2261 | info->feature_fua = 0; |
| 2262 | |
| 2263 | /* |
| 2264 | * If there's no "feature-barrier" defined, then it means |
| 2265 | * we're dealing with a very old backend which writes |
| 2266 | * synchronously; nothing to do. |
| 2267 | * |
| 2268 | * If there are barriers, then we use flush. |
| 2269 | */ |
| 2270 | if (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) { |
| 2271 | info->feature_flush = 1; |
| 2272 | info->feature_fua = 1; |
| 2273 | } |
| 2274 | |
| 2275 | /* |
| 2276 | * And if there is "feature-flush-cache" use that above |
| 2277 | * barriers. |
| 2278 | */ |
| 2279 | if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache", |
| 2280 | 0)) { |
| 2281 | info->feature_flush = 1; |
| 2282 | info->feature_fua = 0; |
| 2283 | } |
| 2284 | |
| 2285 | if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) |
| 2286 | blkfront_setup_discard(info); |
| 2287 | |
| 2288 | if (info->feature_persistent_parm) |
| 2289 | info->feature_persistent = |
| 2290 | !!xenbus_read_unsigned(info->xbdev->otherend, |
| 2291 | "feature-persistent", 0); |
| 2292 | if (info->feature_persistent) |
| 2293 | info->bounce = true; |
| 2294 | |
| 2295 | indirect_segments = xenbus_read_unsigned(info->xbdev->otherend, |
| 2296 | "feature-max-indirect-segments", 0); |
| 2297 | if (indirect_segments > xen_blkif_max_segments) |
| 2298 | indirect_segments = xen_blkif_max_segments; |
| 2299 | if (indirect_segments <= BLKIF_MAX_SEGMENTS_PER_REQUEST) |
| 2300 | indirect_segments = 0; |
| 2301 | info->max_indirect_segments = indirect_segments; |
| 2302 | |
| 2303 | if (info->feature_persistent) { |
| 2304 | mutex_lock(&blkfront_mutex); |
| 2305 | schedule_delayed_work(&blkfront_work, HZ * 10); |
| 2306 | mutex_unlock(&blkfront_mutex); |
| 2307 | } |
| 2308 | } |
| 2309 | |
| 2310 | /* |
| 2311 | * Invoked when the backend is finally 'ready' (and has told produced |
| 2312 | * the details about the physical device - #sectors, size, etc). |
| 2313 | */ |
| 2314 | static void blkfront_connect(struct blkfront_info *info) |
| 2315 | { |
| 2316 | unsigned long long sectors; |
| 2317 | unsigned long sector_size; |
| 2318 | unsigned int physical_sector_size; |
| 2319 | int err, i; |
| 2320 | struct blkfront_ring_info *rinfo; |
| 2321 | |
| 2322 | switch (info->connected) { |
| 2323 | case BLKIF_STATE_CONNECTED: |
| 2324 | /* |
| 2325 | * Potentially, the back-end may be signalling |
| 2326 | * a capacity change; update the capacity. |
| 2327 | */ |
| 2328 | err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, |
| 2329 | "sectors", "%Lu", §ors); |
| 2330 | if (XENBUS_EXIST_ERR(err)) |
| 2331 | return; |
| 2332 | printk(KERN_INFO "Setting capacity to %Lu\n", |
| 2333 | sectors); |
| 2334 | set_capacity_and_notify(info->gd, sectors); |
| 2335 | |
| 2336 | return; |
| 2337 | case BLKIF_STATE_SUSPENDED: |
| 2338 | /* |
| 2339 | * If we are recovering from suspension, we need to wait |
| 2340 | * for the backend to announce it's features before |
| 2341 | * reconnecting, at least we need to know if the backend |
| 2342 | * supports indirect descriptors, and how many. |
| 2343 | */ |
| 2344 | blkif_recover(info); |
| 2345 | return; |
| 2346 | |
| 2347 | default: |
| 2348 | break; |
| 2349 | } |
| 2350 | |
| 2351 | dev_dbg(&info->xbdev->dev, "%s:%s.\n", |
| 2352 | __func__, info->xbdev->otherend); |
| 2353 | |
| 2354 | err = xenbus_gather(XBT_NIL, info->xbdev->otherend, |
| 2355 | "sectors", "%llu", §ors, |
| 2356 | "info", "%u", &info->vdisk_info, |
| 2357 | "sector-size", "%lu", §or_size, |
| 2358 | NULL); |
| 2359 | if (err) { |
| 2360 | xenbus_dev_fatal(info->xbdev, err, |
| 2361 | "reading backend fields at %s", |
| 2362 | info->xbdev->otherend); |
| 2363 | return; |
| 2364 | } |
| 2365 | |
| 2366 | /* |
| 2367 | * physical-sector-size is a newer field, so old backends may not |
| 2368 | * provide this. Assume physical sector size to be the same as |
| 2369 | * sector_size in that case. |
| 2370 | */ |
| 2371 | physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend, |
| 2372 | "physical-sector-size", |
| 2373 | sector_size); |
| 2374 | blkfront_gather_backend_features(info); |
| 2375 | for_each_rinfo(info, rinfo, i) { |
| 2376 | err = blkfront_setup_indirect(rinfo); |
| 2377 | if (err) { |
| 2378 | xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s", |
| 2379 | info->xbdev->otherend); |
| 2380 | blkif_free(info, 0); |
| 2381 | break; |
| 2382 | } |
| 2383 | } |
| 2384 | |
| 2385 | err = xlvbd_alloc_gendisk(sectors, info, sector_size, |
| 2386 | physical_sector_size); |
| 2387 | if (err) { |
| 2388 | xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", |
| 2389 | info->xbdev->otherend); |
| 2390 | goto fail; |
| 2391 | } |
| 2392 | |
| 2393 | xenbus_switch_state(info->xbdev, XenbusStateConnected); |
| 2394 | |
| 2395 | /* Kick pending requests. */ |
| 2396 | info->connected = BLKIF_STATE_CONNECTED; |
| 2397 | for_each_rinfo(info, rinfo, i) |
| 2398 | kick_pending_request_queues(rinfo); |
| 2399 | |
| 2400 | err = device_add_disk(&info->xbdev->dev, info->gd, NULL); |
| 2401 | if (err) { |
| 2402 | put_disk(info->gd); |
| 2403 | blk_mq_free_tag_set(&info->tag_set); |
| 2404 | info->rq = NULL; |
| 2405 | goto fail; |
| 2406 | } |
| 2407 | |
| 2408 | info->is_ready = 1; |
| 2409 | return; |
| 2410 | |
| 2411 | fail: |
| 2412 | blkif_free(info, 0); |
| 2413 | return; |
| 2414 | } |
| 2415 | |
| 2416 | /* |
| 2417 | * Callback received when the backend's state changes. |
| 2418 | */ |
| 2419 | static void blkback_changed(struct xenbus_device *dev, |
| 2420 | enum xenbus_state backend_state) |
| 2421 | { |
| 2422 | struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
| 2423 | |
| 2424 | dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); |
| 2425 | |
| 2426 | switch (backend_state) { |
| 2427 | case XenbusStateInitWait: |
| 2428 | if (dev->state != XenbusStateInitialising) |
| 2429 | break; |
| 2430 | if (talk_to_blkback(dev, info)) |
| 2431 | break; |
| 2432 | break; |
| 2433 | case XenbusStateInitialising: |
| 2434 | case XenbusStateInitialised: |
| 2435 | case XenbusStateReconfiguring: |
| 2436 | case XenbusStateReconfigured: |
| 2437 | case XenbusStateUnknown: |
| 2438 | break; |
| 2439 | |
| 2440 | case XenbusStateConnected: |
| 2441 | /* |
| 2442 | * talk_to_blkback sets state to XenbusStateInitialised |
| 2443 | * and blkfront_connect sets it to XenbusStateConnected |
| 2444 | * (if connection went OK). |
| 2445 | * |
| 2446 | * If the backend (or toolstack) decides to poke at backend |
| 2447 | * state (and re-trigger the watch by setting the state repeatedly |
| 2448 | * to XenbusStateConnected (4)) we need to deal with this. |
| 2449 | * This is allowed as this is used to communicate to the guest |
| 2450 | * that the size of disk has changed! |
| 2451 | */ |
| 2452 | if ((dev->state != XenbusStateInitialised) && |
| 2453 | (dev->state != XenbusStateConnected)) { |
| 2454 | if (talk_to_blkback(dev, info)) |
| 2455 | break; |
| 2456 | } |
| 2457 | |
| 2458 | blkfront_connect(info); |
| 2459 | break; |
| 2460 | |
| 2461 | case XenbusStateClosed: |
| 2462 | if (dev->state == XenbusStateClosed) |
| 2463 | break; |
| 2464 | fallthrough; |
| 2465 | case XenbusStateClosing: |
| 2466 | blkfront_closing(info); |
| 2467 | break; |
| 2468 | } |
| 2469 | } |
| 2470 | |
| 2471 | static void blkfront_remove(struct xenbus_device *xbdev) |
| 2472 | { |
| 2473 | struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); |
| 2474 | |
| 2475 | dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); |
| 2476 | |
| 2477 | if (info->gd) |
| 2478 | del_gendisk(info->gd); |
| 2479 | |
| 2480 | mutex_lock(&blkfront_mutex); |
| 2481 | list_del(&info->info_list); |
| 2482 | mutex_unlock(&blkfront_mutex); |
| 2483 | |
| 2484 | blkif_free(info, 0); |
| 2485 | if (info->gd) { |
| 2486 | xlbd_release_minors(info->gd->first_minor, info->gd->minors); |
| 2487 | put_disk(info->gd); |
| 2488 | blk_mq_free_tag_set(&info->tag_set); |
| 2489 | } |
| 2490 | |
| 2491 | kfree(info); |
| 2492 | } |
| 2493 | |
| 2494 | static int blkfront_is_ready(struct xenbus_device *dev) |
| 2495 | { |
| 2496 | struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
| 2497 | |
| 2498 | return info->is_ready && info->xbdev; |
| 2499 | } |
| 2500 | |
| 2501 | static const struct block_device_operations xlvbd_block_fops = |
| 2502 | { |
| 2503 | .owner = THIS_MODULE, |
| 2504 | .getgeo = blkif_getgeo, |
| 2505 | .ioctl = blkif_ioctl, |
| 2506 | .compat_ioctl = blkdev_compat_ptr_ioctl, |
| 2507 | }; |
| 2508 | |
| 2509 | |
| 2510 | static const struct xenbus_device_id blkfront_ids[] = { |
| 2511 | { "vbd" }, |
| 2512 | { "" } |
| 2513 | }; |
| 2514 | |
| 2515 | static struct xenbus_driver blkfront_driver = { |
| 2516 | .ids = blkfront_ids, |
| 2517 | .probe = blkfront_probe, |
| 2518 | .remove = blkfront_remove, |
| 2519 | .resume = blkfront_resume, |
| 2520 | .otherend_changed = blkback_changed, |
| 2521 | .is_ready = blkfront_is_ready, |
| 2522 | }; |
| 2523 | |
| 2524 | static void purge_persistent_grants(struct blkfront_info *info) |
| 2525 | { |
| 2526 | unsigned int i; |
| 2527 | unsigned long flags; |
| 2528 | struct blkfront_ring_info *rinfo; |
| 2529 | |
| 2530 | for_each_rinfo(info, rinfo, i) { |
| 2531 | struct grant *gnt_list_entry, *tmp; |
| 2532 | LIST_HEAD(grants); |
| 2533 | |
| 2534 | spin_lock_irqsave(&rinfo->ring_lock, flags); |
| 2535 | |
| 2536 | if (rinfo->persistent_gnts_c == 0) { |
| 2537 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 2538 | continue; |
| 2539 | } |
| 2540 | |
| 2541 | list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants, |
| 2542 | node) { |
| 2543 | if (gnt_list_entry->gref == INVALID_GRANT_REF || |
| 2544 | !gnttab_try_end_foreign_access(gnt_list_entry->gref)) |
| 2545 | continue; |
| 2546 | |
| 2547 | list_del(&gnt_list_entry->node); |
| 2548 | rinfo->persistent_gnts_c--; |
| 2549 | gnt_list_entry->gref = INVALID_GRANT_REF; |
| 2550 | list_add_tail(&gnt_list_entry->node, &grants); |
| 2551 | } |
| 2552 | |
| 2553 | list_splice_tail(&grants, &rinfo->grants); |
| 2554 | |
| 2555 | spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
| 2556 | } |
| 2557 | } |
| 2558 | |
| 2559 | static void blkfront_delay_work(struct work_struct *work) |
| 2560 | { |
| 2561 | struct blkfront_info *info; |
| 2562 | bool need_schedule_work = false; |
| 2563 | |
| 2564 | /* |
| 2565 | * Note that when using bounce buffers but not persistent grants |
| 2566 | * there's no need to run blkfront_delay_work because grants are |
| 2567 | * revoked in blkif_completion or else an error is reported and the |
| 2568 | * connection is closed. |
| 2569 | */ |
| 2570 | |
| 2571 | mutex_lock(&blkfront_mutex); |
| 2572 | |
| 2573 | list_for_each_entry(info, &info_list, info_list) { |
| 2574 | if (info->feature_persistent) { |
| 2575 | need_schedule_work = true; |
| 2576 | mutex_lock(&info->mutex); |
| 2577 | purge_persistent_grants(info); |
| 2578 | mutex_unlock(&info->mutex); |
| 2579 | } |
| 2580 | } |
| 2581 | |
| 2582 | if (need_schedule_work) |
| 2583 | schedule_delayed_work(&blkfront_work, HZ * 10); |
| 2584 | |
| 2585 | mutex_unlock(&blkfront_mutex); |
| 2586 | } |
| 2587 | |
| 2588 | static int __init xlblk_init(void) |
| 2589 | { |
| 2590 | int ret; |
| 2591 | int nr_cpus = num_online_cpus(); |
| 2592 | |
| 2593 | if (!xen_domain()) |
| 2594 | return -ENODEV; |
| 2595 | |
| 2596 | if (!xen_has_pv_disk_devices()) |
| 2597 | return -ENODEV; |
| 2598 | |
| 2599 | if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { |
| 2600 | pr_warn("xen_blk: can't get major %d with name %s\n", |
| 2601 | XENVBD_MAJOR, DEV_NAME); |
| 2602 | return -ENODEV; |
| 2603 | } |
| 2604 | |
| 2605 | if (xen_blkif_max_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST) |
| 2606 | xen_blkif_max_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| 2607 | |
| 2608 | if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) { |
| 2609 | pr_info("Invalid max_ring_order (%d), will use default max: %d.\n", |
| 2610 | xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER); |
| 2611 | xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER; |
| 2612 | } |
| 2613 | |
| 2614 | if (xen_blkif_max_queues > nr_cpus) { |
| 2615 | pr_info("Invalid max_queues (%d), will use default max: %d.\n", |
| 2616 | xen_blkif_max_queues, nr_cpus); |
| 2617 | xen_blkif_max_queues = nr_cpus; |
| 2618 | } |
| 2619 | |
| 2620 | INIT_DELAYED_WORK(&blkfront_work, blkfront_delay_work); |
| 2621 | |
| 2622 | ret = xenbus_register_frontend(&blkfront_driver); |
| 2623 | if (ret) { |
| 2624 | unregister_blkdev(XENVBD_MAJOR, DEV_NAME); |
| 2625 | return ret; |
| 2626 | } |
| 2627 | |
| 2628 | return 0; |
| 2629 | } |
| 2630 | module_init(xlblk_init); |
| 2631 | |
| 2632 | |
| 2633 | static void __exit xlblk_exit(void) |
| 2634 | { |
| 2635 | cancel_delayed_work_sync(&blkfront_work); |
| 2636 | |
| 2637 | xenbus_unregister_driver(&blkfront_driver); |
| 2638 | unregister_blkdev(XENVBD_MAJOR, DEV_NAME); |
| 2639 | kfree(minors); |
| 2640 | } |
| 2641 | module_exit(xlblk_exit); |
| 2642 | |
| 2643 | MODULE_DESCRIPTION("Xen virtual block device frontend"); |
| 2644 | MODULE_LICENSE("GPL"); |
| 2645 | MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); |
| 2646 | MODULE_ALIAS("xen:vbd"); |
| 2647 | MODULE_ALIAS("xenblk"); |