fs/bio-integrity.c

   1 /*
   2  * bio-integrity.c - bio data integrity extensions
   3  *
   4  * Copyright (C) 2007, 2008, 2009 Oracle Corporation
   5  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; see the file COPYING.  If not, write to
  18  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  19  * USA.
  20  *
  21  */
  22
  23 #include <linux/blkdev.h>
  24 #include <linux/mempool.h>
  25 #include <linux/bio.h>
  26 #include <linux/workqueue.h>
  27
  28 struct integrity_slab {
  29         struct kmem_cache *slab;
  30         unsigned short nr_vecs;
  31         char name[8];
  32 };
  33
  34 #define IS(x) { .nr_vecs = x, .name = "bip-"__stringify(x) }
  35 struct integrity_slab bip_slab[BIOVEC_NR_POOLS] __read_mostly = {
  36         IS(1), IS(4), IS(16), IS(64), IS(128), IS(BIO_MAX_PAGES),
  37 };
  38 #undef IS
  39
  40 static struct workqueue_struct *kintegrityd_wq;
  41
  42 static inline unsigned int vecs_to_idx(unsigned int nr)
  43 {
  44         switch (nr) {
  45         case 1:
  46                 return 0;
  47         case 2 ... 4:
  48                 return 1;
  49         case 5 ... 16:
  50                 return 2;
  51         case 17 ... 64:
  52                 return 3;
  53         case 65 ... 128:
  54                 return 4;
  55         case 129 ... BIO_MAX_PAGES:
  56                 return 5;
  57         default:
  58                 BUG();
  59         }
  60 }
  61
  62 static inline int use_bip_pool(unsigned int idx)
  63 {
  64         if (idx == BIOVEC_NR_POOLS)
  65                 return 1;
  66
  67         return 0;
  68 }
  69
  70 /**
  71  * bio_integrity_alloc_bioset - Allocate integrity payload and attach it to bio
  72  * @bio:        bio to attach integrity metadata to
  73  * @gfp_mask:   Memory allocation mask
  74  * @nr_vecs:    Number of integrity metadata scatter-gather elements
  75  * @bs:         bio_set to allocate from
  76  *
  77  * Description: This function prepares a bio for attaching integrity
  78  * metadata.  nr_vecs specifies the maximum number of pages containing
  79  * integrity metadata that can be attached.
  80  */
  81 struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *bio,
  82                                                          gfp_t gfp_mask,
  83                                                          unsigned int nr_vecs,
  84                                                          struct bio_set *bs)
  85 {
  86         struct bio_integrity_payload *bip;
  87         unsigned int idx = vecs_to_idx(nr_vecs);
  88
  89         BUG_ON(bio == NULL);
  90         bip = NULL;
  91
  92         /* Lower order allocations come straight from slab */
  93         if (!use_bip_pool(idx))
  94                 bip = kmem_cache_alloc(bip_slab[idx].slab, gfp_mask);
  95
  96         /* Use mempool if lower order alloc failed or max vecs were requested */
  97         if (bip == NULL) {
  98                 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
  99
 100                 if (unlikely(bip == NULL)) {
 101                         printk(KERN_ERR "%s: could not alloc bip\n", __func__);
 102                         return NULL;
 103                 }
 104         }
 105
 106         memset(bip, 0, sizeof(*bip));
 107
 108         bip->bip_slab = idx;
 109         bip->bip_bio = bio;
 110         bio->bi_integrity = bip;
 111
 112         return bip;
 113 }
 114 EXPORT_SYMBOL(bio_integrity_alloc_bioset);
 115
 116 /**
 117  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
 118  * @bio:        bio to attach integrity metadata to
 119  * @gfp_mask:   Memory allocation mask
 120  * @nr_vecs:    Number of integrity metadata scatter-gather elements
 121  *
 122  * Description: This function prepares a bio for attaching integrity
 123  * metadata.  nr_vecs specifies the maximum number of pages containing
 124  * integrity metadata that can be attached.
 125  */
 126 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 127                                                   gfp_t gfp_mask,
 128                                                   unsigned int nr_vecs)
 129 {
 130         return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set);
 131 }
 132 EXPORT_SYMBOL(bio_integrity_alloc);
 133
 134 /**
 135  * bio_integrity_free - Free bio integrity payload
 136  * @bio:        bio containing bip to be freed
 137  * @bs:         bio_set this bio was allocated from
 138  *
 139  * Description: Used to free the integrity portion of a bio. Usually
 140  * called from bio_free().
 141  */
 142 void bio_integrity_free(struct bio *bio, struct bio_set *bs)
 143 {
 144         struct bio_integrity_payload *bip = bio->bi_integrity;
 145
 146         BUG_ON(bip == NULL);
 147
 148         /* A cloned bio doesn't own the integrity metadata */
 149         if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
 150             && bip->bip_buf != NULL)
 151                 kfree(bip->bip_buf);
 152
 153         if (use_bip_pool(bip->bip_slab))
 154                 mempool_free(bip, bs->bio_integrity_pool);
 155         else
 156                 kmem_cache_free(bip_slab[bip->bip_slab].slab, bip);
 157
 158         bio->bi_integrity = NULL;
 159 }
 160 EXPORT_SYMBOL(bio_integrity_free);
 161
 162 /**
 163  * bio_integrity_add_page - Attach integrity metadata
 164  * @bio:        bio to update
 165  * @page:       page containing integrity metadata
 166  * @len:        number of bytes of integrity metadata in page
 167  * @offset:     start offset within page
 168  *
 169  * Description: Attach a page containing integrity metadata to bio.
 170  */
 171 int bio_integrity_add_page(struct bio *bio, struct page *page,
 172                            unsigned int len, unsigned int offset)
 173 {
 174         struct bio_integrity_payload *bip = bio->bi_integrity;
 175         struct bio_vec *iv;
 176
 177         if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
 178                 printk(KERN_ERR "%s: bip_vec full\n", __func__);
 179                 return 0;
 180         }
 181
 182         iv = bip_vec_idx(bip, bip->bip_vcnt);
 183         BUG_ON(iv == NULL);
 184
 185         iv->bv_page = page;
 186         iv->bv_len = len;
 187         iv->bv_offset = offset;
 188         bip->bip_vcnt++;
 189
 190         return len;
 191 }
 192 EXPORT_SYMBOL(bio_integrity_add_page);
 193
 194 static int bdev_integrity_enabled(struct block_device *bdev, int rw)
 195 {
 196         struct blk_integrity *bi = bdev_get_integrity(bdev);
 197
 198         if (bi == NULL)
 199                 return 0;
 200
 201         if (rw == READ && bi->verify_fn != NULL &&
 202             (bi->flags & INTEGRITY_FLAG_READ))
 203                 return 1;
 204
 205         if (rw == WRITE && bi->generate_fn != NULL &&
 206             (bi->flags & INTEGRITY_FLAG_WRITE))
 207                 return 1;
 208
 209         return 0;
 210 }
 211
 212 /**
 213  * bio_integrity_enabled - Check whether integrity can be passed
 214  * @bio:        bio to check
 215  *
 216  * Description: Determines whether bio_integrity_prep() can be called
 217  * on this bio or not.  bio data direction and target device must be
 218  * set prior to calling.  The functions honors the write_generate and
 219  * read_verify flags in sysfs.
 220  */
 221 int bio_integrity_enabled(struct bio *bio)
 222 {
 223         /* Already protected? */
 224         if (bio_integrity(bio))
 225                 return 0;
 226
 227         return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio));
 228 }
 229 EXPORT_SYMBOL(bio_integrity_enabled);
 230
 231 /**
 232  * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
 233  * @bi:         blk_integrity profile for device
 234  * @sectors:    Number of 512 sectors to convert
 235  *
 236  * Description: The block layer calculates everything in 512 byte
 237  * sectors but integrity metadata is done in terms of the hardware
 238  * sector size of the storage device.  Convert the block layer sectors
 239  * to physical sectors.
 240  */
 241 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi,
 242                                                     unsigned int sectors)
 243 {
 244         /* At this point there are only 512b or 4096b DIF/EPP devices */
 245         if (bi->sector_size == 4096)
 246                 return sectors >>= 3;
 247
 248         return sectors;
 249 }
 250
 251 /**
 252  * bio_integrity_tag_size - Retrieve integrity tag space
 253  * @bio:        bio to inspect
 254  *
 255  * Description: Returns the maximum number of tag bytes that can be
 256  * attached to this bio. Filesystems can use this to determine how
 257  * much metadata to attach to an I/O.
 258  */
 259 unsigned int bio_integrity_tag_size(struct bio *bio)
 260 {
 261         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 262
 263         BUG_ON(bio->bi_size == 0);
 264
 265         return bi->tag_size * (bio->bi_size / bi->sector_size);
 266 }
 267 EXPORT_SYMBOL(bio_integrity_tag_size);
 268
 269 int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set)
 270 {
 271         struct bio_integrity_payload *bip = bio->bi_integrity;
 272         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 273         unsigned int nr_sectors;
 274
 275         BUG_ON(bip->bip_buf == NULL);
 276
 277         if (bi->tag_size == 0)
 278                 return -1;
 279
 280         nr_sectors = bio_integrity_hw_sectors(bi,
 281                                         DIV_ROUND_UP(len, bi->tag_size));
 282
 283         if (nr_sectors * bi->tuple_size > bip->bip_size) {
 284                 printk(KERN_ERR "%s: tag too big for bio: %u > %u\n",
 285                        __func__, nr_sectors * bi->tuple_size, bip->bip_size);
 286                 return -1;
 287         }
 288
 289         if (set)
 290                 bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
 291         else
 292                 bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
 293
 294         return 0;
 295 }
 296
 297 /**
 298  * bio_integrity_set_tag - Attach a tag buffer to a bio
 299  * @bio:        bio to attach buffer to
 300  * @tag_buf:    Pointer to a buffer containing tag data
 301  * @len:        Length of the included buffer
 302  *
 303  * Description: Use this function to tag a bio by leveraging the extra
 304  * space provided by devices formatted with integrity protection.  The
 305  * size of the integrity buffer must be <= to the size reported by
 306  * bio_integrity_tag_size().
 307  */
 308 int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len)
 309 {
 310         BUG_ON(bio_data_dir(bio) != WRITE);
 311
 312         return bio_integrity_tag(bio, tag_buf, len, 1);
 313 }
 314 EXPORT_SYMBOL(bio_integrity_set_tag);
 315
 316 /**
 317  * bio_integrity_get_tag - Retrieve a tag buffer from a bio
 318  * @bio:        bio to retrieve buffer from
 319  * @tag_buf:    Pointer to a buffer for the tag data
 320  * @len:        Length of the target buffer
 321  *
 322  * Description: Use this function to retrieve the tag buffer from a
 323  * completed I/O. The size of the integrity buffer must be <= to the
 324  * size reported by bio_integrity_tag_size().
 325  */
 326 int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
 327 {
 328         BUG_ON(bio_data_dir(bio) != READ);
 329
 330         return bio_integrity_tag(bio, tag_buf, len, 0);
 331 }
 332 EXPORT_SYMBOL(bio_integrity_get_tag);
 333
 334 /**
 335  * bio_integrity_generate - Generate integrity metadata for a bio
 336  * @bio:        bio to generate integrity metadata for
 337  *
 338  * Description: Generates integrity metadata for a bio by calling the
 339  * block device's generation callback function.  The bio must have a
 340  * bip attached with enough room to accommodate the generated
 341  * integrity metadata.
 342  */
 343 static void bio_integrity_generate(struct bio *bio)
 344 {
 345         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 346         struct blk_integrity_exchg bix;
 347         struct bio_vec *bv;
 348         sector_t sector = bio->bi_sector;
 349         unsigned int i, sectors, total;
 350         void *prot_buf = bio->bi_integrity->bip_buf;
 351
 352         total = 0;
 353         bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 354         bix.sector_size = bi->sector_size;
 355
 356         bio_for_each_segment(bv, bio, i) {
 357                 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
 358                 bix.data_buf = kaddr + bv->bv_offset;
 359                 bix.data_size = bv->bv_len;
 360                 bix.prot_buf = prot_buf;
 361                 bix.sector = sector;
 362
 363                 bi->generate_fn(&bix);
 364
 365                 sectors = bv->bv_len / bi->sector_size;
 366                 sector += sectors;
 367                 prot_buf += sectors * bi->tuple_size;
 368                 total += sectors * bi->tuple_size;
 369                 BUG_ON(total > bio->bi_integrity->bip_size);
 370
 371                 kunmap_atomic(kaddr, KM_USER0);
 372         }
 373 }
 374
 375 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
 376 {
 377         if (bi)
 378                 return bi->tuple_size;
 379
 380         return 0;
 381 }
 382
 383 /**
 384  * bio_integrity_prep - Prepare bio for integrity I/O
 385  * @bio:        bio to prepare
 386  *
 387  * Description: Allocates a buffer for integrity metadata, maps the
 388  * pages and attaches them to a bio.  The bio must have data
 389  * direction, target device and start sector set priot to calling.  In
 390  * the WRITE case, integrity metadata will be generated using the
 391  * block device's integrity function.  In the READ case, the buffer
 392  * will be prepared for DMA and a suitable end_io handler set up.
 393  */
 394 int bio_integrity_prep(struct bio *bio)
 395 {
 396         struct bio_integrity_payload *bip;
 397         struct blk_integrity *bi;
 398         struct request_queue *q;
 399         void *buf;
 400         unsigned long start, end;
 401         unsigned int len, nr_pages;
 402         unsigned int bytes, offset, i;
 403         unsigned int sectors;
 404
 405         bi = bdev_get_integrity(bio->bi_bdev);
 406         q = bdev_get_queue(bio->bi_bdev);
 407         BUG_ON(bi == NULL);
 408         BUG_ON(bio_integrity(bio));
 409
 410         sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
 411
 412         /* Allocate kernel buffer for protection data */
 413         len = sectors * blk_integrity_tuple_size(bi);
 414         buf = kmalloc(len, GFP_NOIO | __GFP_NOFAIL | q->bounce_gfp);
 415         if (unlikely(buf == NULL)) {
 416                 printk(KERN_ERR "could not allocate integrity buffer\n");
 417                 return -EIO;
 418         }
 419
 420         end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 421         start = ((unsigned long) buf) >> PAGE_SHIFT;
 422         nr_pages = end - start;
 423
 424         /* Allocate bio integrity payload and integrity vectors */
 425         bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
 426         if (unlikely(bip == NULL)) {
 427                 printk(KERN_ERR "could not allocate data integrity bioset\n");
 428                 kfree(buf);
 429                 return -EIO;
 430         }
 431
 432         bip->bip_buf = buf;
 433         bip->bip_size = len;
 434         bip->bip_sector = bio->bi_sector;
 435
 436         /* Map it */
 437         offset = offset_in_page(buf);
 438         for (i = 0 ; i < nr_pages ; i++) {
 439                 int ret;
 440                 bytes = PAGE_SIZE - offset;
 441
 442                 if (len <= 0)
 443                         break;
 444
 445                 if (bytes > len)
 446                         bytes = len;
 447
 448                 ret = bio_integrity_add_page(bio, virt_to_page(buf),
 449                                              bytes, offset);
 450
 451                 if (ret == 0)
 452                         return 0;
 453
 454                 if (ret < bytes)
 455                         break;
 456
 457                 buf += bytes;
 458                 len -= bytes;
 459                 offset = 0;
 460         }
 461
 462         /* Install custom I/O completion handler if read verify is enabled */
 463         if (bio_data_dir(bio) == READ) {
 464                 bip->bip_end_io = bio->bi_end_io;
 465                 bio->bi_end_io = bio_integrity_endio;
 466         }
 467
 468         /* Auto-generate integrity metadata if this is a write */
 469         if (bio_data_dir(bio) == WRITE)
 470                 bio_integrity_generate(bio);
 471
 472         return 0;
 473 }
 474 EXPORT_SYMBOL(bio_integrity_prep);
 475
 476 /**
 477  * bio_integrity_verify - Verify integrity metadata for a bio
 478  * @bio:        bio to verify
 479  *
 480  * Description: This function is called to verify the integrity of a
 481  * bio.  The data in the bio io_vec is compared to the integrity
 482  * metadata returned by the HBA.
 483  */
 484 static int bio_integrity_verify(struct bio *bio)
 485 {
 486         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 487         struct blk_integrity_exchg bix;
 488         struct bio_vec *bv;
 489         sector_t sector = bio->bi_integrity->bip_sector;
 490         unsigned int i, sectors, total, ret;
 491         void *prot_buf = bio->bi_integrity->bip_buf;
 492
 493         ret = total = 0;
 494         bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 495         bix.sector_size = bi->sector_size;
 496
 497         bio_for_each_segment(bv, bio, i) {
 498                 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
 499                 bix.data_buf = kaddr + bv->bv_offset;
 500                 bix.data_size = bv->bv_len;
 501                 bix.prot_buf = prot_buf;
 502                 bix.sector = sector;
 503
 504                 ret = bi->verify_fn(&bix);
 505
 506                 if (ret) {
 507                         kunmap_atomic(kaddr, KM_USER0);
 508                         return ret;
 509                 }
 510
 511                 sectors = bv->bv_len / bi->sector_size;
 512                 sector += sectors;
 513                 prot_buf += sectors * bi->tuple_size;
 514                 total += sectors * bi->tuple_size;
 515                 BUG_ON(total > bio->bi_integrity->bip_size);
 516
 517                 kunmap_atomic(kaddr, KM_USER0);
 518         }
 519
 520         return ret;
 521 }
 522
 523 /**
 524  * bio_integrity_verify_fn - Integrity I/O completion worker
 525  * @work:       Work struct stored in bio to be verified
 526  *
 527  * Description: This workqueue function is called to complete a READ
 528  * request.  The function verifies the transferred integrity metadata
 529  * and then calls the original bio end_io function.
 530  */
 531 static void bio_integrity_verify_fn(struct work_struct *work)
 532 {
 533         struct bio_integrity_payload *bip =
 534                 container_of(work, struct bio_integrity_payload, bip_work);
 535         struct bio *bio = bip->bip_bio;
 536         int error;
 537
 538         error = bio_integrity_verify(bio);
 539
 540         /* Restore original bio completion handler */
 541         bio->bi_end_io = bip->bip_end_io;
 542         bio_endio(bio, error);
 543 }
 544
 545 /**
 546  * bio_integrity_endio - Integrity I/O completion function
 547  * @bio:        Protected bio
 548  * @error:      Pointer to errno
 549  *
 550  * Description: Completion for integrity I/O
 551  *
 552  * Normally I/O completion is done in interrupt context.  However,
 553  * verifying I/O integrity is a time-consuming task which must be run
 554  * in process context.  This function postpones completion
 555  * accordingly.
 556  */
 557 void bio_integrity_endio(struct bio *bio, int error)
 558 {
 559         struct bio_integrity_payload *bip = bio->bi_integrity;
 560
 561         BUG_ON(bip->bip_bio != bio);
 562
 563         /* In case of an I/O error there is no point in verifying the
 564          * integrity metadata.  Restore original bio end_io handler
 565          * and run it.
 566          */
 567         if (error) {
 568                 bio->bi_end_io = bip->bip_end_io;
 569                 bio_endio(bio, error);
 570
 571                 return;
 572         }
 573
 574         INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 575         queue_work(kintegrityd_wq, &bip->bip_work);
 576 }
 577 EXPORT_SYMBOL(bio_integrity_endio);
 578
 579 /**
 580  * bio_integrity_mark_head - Advance bip_vec skip bytes
 581  * @bip:        Integrity vector to advance
 582  * @skip:       Number of bytes to advance it
 583  */
 584 void bio_integrity_mark_head(struct bio_integrity_payload *bip,
 585                              unsigned int skip)
 586 {
 587         struct bio_vec *iv;
 588         unsigned int i;
 589
 590         bip_for_each_vec(iv, bip, i) {
 591                 if (skip == 0) {
 592                         bip->bip_idx = i;
 593                         return;
 594                 } else if (skip >= iv->bv_len) {
 595                         skip -= iv->bv_len;
 596                 } else { /* skip < iv->bv_len) */
 597                         iv->bv_offset += skip;
 598                         iv->bv_len -= skip;
 599                         bip->bip_idx = i;
 600                         return;
 601                 }
 602         }
 603 }
 604
 605 /**
 606  * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long
 607  * @bip:        Integrity vector to truncate
 608  * @len:        New length of integrity vector
 609  */
 610 void bio_integrity_mark_tail(struct bio_integrity_payload *bip,
 611                              unsigned int len)
 612 {
 613         struct bio_vec *iv;
 614         unsigned int i;
 615
 616         bip_for_each_vec(iv, bip, i) {
 617                 if (len == 0) {
 618                         bip->bip_vcnt = i;
 619                         return;
 620                 } else if (len >= iv->bv_len) {
 621                         len -= iv->bv_len;
 622                 } else { /* len < iv->bv_len) */
 623                         iv->bv_len = len;
 624                         len = 0;
 625                 }
 626         }
 627 }
 628
 629 /**
 630  * bio_integrity_advance - Advance integrity vector
 631  * @bio:        bio whose integrity vector to update
 632  * @bytes_done: number of data bytes that have been completed
 633  *
 634  * Description: This function calculates how many integrity bytes the
 635  * number of completed data bytes correspond to and advances the
 636  * integrity vector accordingly.
 637  */
 638 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 639 {
 640         struct bio_integrity_payload *bip = bio->bi_integrity;
 641         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 642         unsigned int nr_sectors;
 643
 644         BUG_ON(bip == NULL);
 645         BUG_ON(bi == NULL);
 646
 647         nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9);
 648         bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size);
 649 }
 650 EXPORT_SYMBOL(bio_integrity_advance);
 651
 652 /**
 653  * bio_integrity_trim - Trim integrity vector
 654  * @bio:        bio whose integrity vector to update
 655  * @offset:     offset to first data sector
 656  * @sectors:    number of data sectors
 657  *
 658  * Description: Used to trim the integrity vector in a cloned bio.
 659  * The ivec will be advanced corresponding to 'offset' data sectors
 660  * and the length will be truncated corresponding to 'len' data
 661  * sectors.
 662  */
 663 void bio_integrity_trim(struct bio *bio, unsigned int offset,
 664                         unsigned int sectors)
 665 {
 666         struct bio_integrity_payload *bip = bio->bi_integrity;
 667         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 668         unsigned int nr_sectors;
 669
 670         BUG_ON(bip == NULL);
 671         BUG_ON(bi == NULL);
 672         BUG_ON(!bio_flagged(bio, BIO_CLONED));
 673
 674         nr_sectors = bio_integrity_hw_sectors(bi, sectors);
 675         bip->bip_sector = bip->bip_sector + offset;
 676         bio_integrity_mark_head(bip, offset * bi->tuple_size);
 677         bio_integrity_mark_tail(bip, sectors * bi->tuple_size);
 678 }
 679 EXPORT_SYMBOL(bio_integrity_trim);
 680
 681 /**
 682  * bio_integrity_split - Split integrity metadata
 683  * @bio:        Protected bio
 684  * @bp:         Resulting bio_pair
 685  * @sectors:    Offset
 686  *
 687  * Description: Splits an integrity page into a bio_pair.
 688  */
 689 void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
 690 {
 691         struct blk_integrity *bi;
 692         struct bio_integrity_payload *bip = bio->bi_integrity;
 693         unsigned int nr_sectors;
 694
 695         if (bio_integrity(bio) == 0)
 696                 return;
 697
 698         bi = bdev_get_integrity(bio->bi_bdev);
 699         BUG_ON(bi == NULL);
 700         BUG_ON(bip->bip_vcnt != 1);
 701
 702         nr_sectors = bio_integrity_hw_sectors(bi, sectors);
 703
 704         bp->bio1.bi_integrity = &bp->bip1;
 705         bp->bio2.bi_integrity = &bp->bip2;
 706
 707         bp->iv1 = bip->bip_vec[0];
 708         bp->iv2 = bip->bip_vec[0];
 709
 710         bp->bip1.bip_vec[0] = bp->iv1;
 711         bp->bip2.bip_vec[0] = bp->iv2;
 712
 713         bp->iv1.bv_len = sectors * bi->tuple_size;
 714         bp->iv2.bv_offset += sectors * bi->tuple_size;
 715         bp->iv2.bv_len -= sectors * bi->tuple_size;
 716
 717         bp->bip1.bip_sector = bio->bi_integrity->bip_sector;
 718         bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors;
 719
 720         bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1;
 721         bp->bip1.bip_idx = bp->bip2.bip_idx = 0;
 722 }
 723 EXPORT_SYMBOL(bio_integrity_split);
 724
 725 /**
 726  * bio_integrity_clone - Callback for cloning bios with integrity metadata
 727  * @bio:        New bio
 728  * @bio_src:    Original bio
 729  * @gfp_mask:   Memory allocation mask
 730  * @bs:         bio_set to allocate bip from
 731  *
 732  * Description: Called to allocate a bip when cloning a bio
 733  */
 734 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 735                         gfp_t gfp_mask, struct bio_set *bs)
 736 {
 737         struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
 738         struct bio_integrity_payload *bip;
 739
 740         BUG_ON(bip_src == NULL);
 741
 742         bip = bio_integrity_alloc_bioset(bio, gfp_mask, bip_src->bip_vcnt, bs);
 743
 744         if (bip == NULL)
 745                 return -EIO;
 746
 747         memcpy(bip->bip_vec, bip_src->bip_vec,
 748                bip_src->bip_vcnt * sizeof(struct bio_vec));
 749
 750         bip->bip_sector = bip_src->bip_sector;
 751         bip->bip_vcnt = bip_src->bip_vcnt;
 752         bip->bip_idx = bip_src->bip_idx;
 753
 754         return 0;
 755 }
 756 EXPORT_SYMBOL(bio_integrity_clone);
 757
 758 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 759 {
 760         unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
 761
 762         bs->bio_integrity_pool =
 763                 mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
 764
 765         if (!bs->bio_integrity_pool)
 766                 return -1;
 767
 768         return 0;
 769 }
 770 EXPORT_SYMBOL(bioset_integrity_create);
 771
 772 void bioset_integrity_free(struct bio_set *bs)
 773 {
 774         if (bs->bio_integrity_pool)
 775                 mempool_destroy(bs->bio_integrity_pool);
 776 }
 777 EXPORT_SYMBOL(bioset_integrity_free);
 778
 779 void __init bio_integrity_init(void)
 780 {
 781         unsigned int i;
 782
 783         kintegrityd_wq = create_workqueue("kintegrityd");
 784         if (!kintegrityd_wq)
 785                 panic("Failed to create kintegrityd\n");
 786
 787         for (i = 0 ; i < BIOVEC_NR_POOLS ; i++) {
 788                 unsigned int size;
 789
 790                 size = sizeof(struct bio_integrity_payload)
 791                         + bip_slab[i].nr_vecs * sizeof(struct bio_vec);
 792
 793                 bip_slab[i].slab =
 794                         kmem_cache_create(bip_slab[i].name, size, 0,
 795                                           SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 796         }
 797 }