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/export.h>
  26 #include <linux/bio.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29
  30 struct integrity_slab {
  31         struct kmem_cache *slab;
  32         unsigned short nr_vecs;
  33         char name[8];
  34 };
  35
  36 #define IS(x) { .nr_vecs = x, .name = "bip-"__stringify(x) }
  37 struct integrity_slab bip_slab[BIOVEC_NR_POOLS] __read_mostly = {
  38         IS(1), IS(4), IS(16), IS(64), IS(128), IS(BIO_MAX_PAGES),
  39 };
  40 #undef IS
  41
  42 static struct workqueue_struct *kintegrityd_wq;
  43
  44 static inline unsigned int vecs_to_idx(unsigned int nr)
  45 {
  46         switch (nr) {
  47         case 1:
  48                 return 0;
  49         case 2 ... 4:
  50                 return 1;
  51         case 5 ... 16:
  52                 return 2;
  53         case 17 ... 64:
  54                 return 3;
  55         case 65 ... 128:
  56                 return 4;
  57         case 129 ... BIO_MAX_PAGES:
  58                 return 5;
  59         default:
  60                 BUG();
  61         }
  62 }
  63
  64 static inline int use_bip_pool(unsigned int idx)
  65 {
  66         if (idx == BIOVEC_MAX_IDX)
  67                 return 1;
  68
  69         return 0;
  70 }
  71
  72 /**
  73  * bio_integrity_alloc_bioset - Allocate integrity payload and attach it to bio
  74  * @bio:        bio to attach integrity metadata to
  75  * @gfp_mask:   Memory allocation mask
  76  * @nr_vecs:    Number of integrity metadata scatter-gather elements
  77  * @bs:         bio_set to allocate from
  78  *
  79  * Description: This function prepares a bio for attaching integrity
  80  * metadata.  nr_vecs specifies the maximum number of pages containing
  81  * integrity metadata that can be attached.
  82  */
  83 struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *bio,
  84                                                          gfp_t gfp_mask,
  85                                                          unsigned int nr_vecs,
  86                                                          struct bio_set *bs)
  87 {
  88         struct bio_integrity_payload *bip;
  89         unsigned int idx = vecs_to_idx(nr_vecs);
  90
  91         BUG_ON(bio == NULL);
  92         bip = NULL;
  93
  94         /* Lower order allocations come straight from slab */
  95         if (!use_bip_pool(idx))
  96                 bip = kmem_cache_alloc(bip_slab[idx].slab, gfp_mask);
  97
  98         /* Use mempool if lower order alloc failed or max vecs were requested */
  99         if (bip == NULL) {
 100                 idx = BIOVEC_MAX_IDX;  /* so we free the payload properly later */
 101                 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
 102
 103                 if (unlikely(bip == NULL)) {
 104                         printk(KERN_ERR "%s: could not alloc bip\n", __func__);
 105                         return NULL;
 106                 }
 107         }
 108
 109         memset(bip, 0, sizeof(*bip));
 110
 111         bip->bip_slab = idx;
 112         bip->bip_bio = bio;
 113         bio->bi_integrity = bip;
 114
 115         return bip;
 116 }
 117 EXPORT_SYMBOL(bio_integrity_alloc_bioset);
 118
 119 /**
 120  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
 121  * @bio:        bio to attach integrity metadata to
 122  * @gfp_mask:   Memory allocation mask
 123  * @nr_vecs:    Number of integrity metadata scatter-gather elements
 124  *
 125  * Description: This function prepares a bio for attaching integrity
 126  * metadata.  nr_vecs specifies the maximum number of pages containing
 127  * integrity metadata that can be attached.
 128  */
 129 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 130                                                   gfp_t gfp_mask,
 131                                                   unsigned int nr_vecs)
 132 {
 133         return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set);
 134 }
 135 EXPORT_SYMBOL(bio_integrity_alloc);
 136
 137 /**
 138  * bio_integrity_free - Free bio integrity payload
 139  * @bio:        bio containing bip to be freed
 140  * @bs:         bio_set this bio was allocated from
 141  *
 142  * Description: Used to free the integrity portion of a bio. Usually
 143  * called from bio_free().
 144  */
 145 void bio_integrity_free(struct bio *bio, struct bio_set *bs)
 146 {
 147         struct bio_integrity_payload *bip = bio->bi_integrity;
 148
 149         BUG_ON(bip == NULL);
 150
 151         /* A cloned bio doesn't own the integrity metadata */
 152         if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
 153             && bip->bip_buf != NULL)
 154                 kfree(bip->bip_buf);
 155
 156         if (use_bip_pool(bip->bip_slab))
 157                 mempool_free(bip, bs->bio_integrity_pool);
 158         else
 159                 kmem_cache_free(bip_slab[bip->bip_slab].slab, bip);
 160
 161         bio->bi_integrity = NULL;
 162 }
 163 EXPORT_SYMBOL(bio_integrity_free);
 164
 165 /**
 166  * bio_integrity_add_page - Attach integrity metadata
 167  * @bio:        bio to update
 168  * @page:       page containing integrity metadata
 169  * @len:        number of bytes of integrity metadata in page
 170  * @offset:     start offset within page
 171  *
 172  * Description: Attach a page containing integrity metadata to bio.
 173  */
 174 int bio_integrity_add_page(struct bio *bio, struct page *page,
 175                            unsigned int len, unsigned int offset)
 176 {
 177         struct bio_integrity_payload *bip = bio->bi_integrity;
 178         struct bio_vec *iv;
 179
 180         if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
 181                 printk(KERN_ERR "%s: bip_vec full\n", __func__);
 182                 return 0;
 183         }
 184
 185         iv = bip_vec_idx(bip, bip->bip_vcnt);
 186         BUG_ON(iv == NULL);
 187
 188         iv->bv_page = page;
 189         iv->bv_len = len;
 190         iv->bv_offset = offset;
 191         bip->bip_vcnt++;
 192
 193         return len;
 194 }
 195 EXPORT_SYMBOL(bio_integrity_add_page);
 196
 197 static int bdev_integrity_enabled(struct block_device *bdev, int rw)
 198 {
 199         struct blk_integrity *bi = bdev_get_integrity(bdev);
 200
 201         if (bi == NULL)
 202                 return 0;
 203
 204         if (rw == READ && bi->verify_fn != NULL &&
 205             (bi->flags & INTEGRITY_FLAG_READ))
 206                 return 1;
 207
 208         if (rw == WRITE && bi->generate_fn != NULL &&
 209             (bi->flags & INTEGRITY_FLAG_WRITE))
 210                 return 1;
 211
 212         return 0;
 213 }
 214
 215 /**
 216  * bio_integrity_enabled - Check whether integrity can be passed
 217  * @bio:        bio to check
 218  *
 219  * Description: Determines whether bio_integrity_prep() can be called
 220  * on this bio or not.  bio data direction and target device must be
 221  * set prior to calling.  The functions honors the write_generate and
 222  * read_verify flags in sysfs.
 223  */
 224 int bio_integrity_enabled(struct bio *bio)
 225 {
 226         /* Already protected? */
 227         if (bio_integrity(bio))
 228                 return 0;
 229
 230         return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio));
 231 }
 232 EXPORT_SYMBOL(bio_integrity_enabled);
 233
 234 /**
 235  * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
 236  * @bi:         blk_integrity profile for device
 237  * @sectors:    Number of 512 sectors to convert
 238  *
 239  * Description: The block layer calculates everything in 512 byte
 240  * sectors but integrity metadata is done in terms of the hardware
 241  * sector size of the storage device.  Convert the block layer sectors
 242  * to physical sectors.
 243  */
 244 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi,
 245                                                     unsigned int sectors)
 246 {
 247         /* At this point there are only 512b or 4096b DIF/EPP devices */
 248         if (bi->sector_size == 4096)
 249                 return sectors >>= 3;
 250
 251         return sectors;
 252 }
 253
 254 /**
 255  * bio_integrity_tag_size - Retrieve integrity tag space
 256  * @bio:        bio to inspect
 257  *
 258  * Description: Returns the maximum number of tag bytes that can be
 259  * attached to this bio. Filesystems can use this to determine how
 260  * much metadata to attach to an I/O.
 261  */
 262 unsigned int bio_integrity_tag_size(struct bio *bio)
 263 {
 264         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 265
 266         BUG_ON(bio->bi_size == 0);
 267
 268         return bi->tag_size * (bio->bi_size / bi->sector_size);
 269 }
 270 EXPORT_SYMBOL(bio_integrity_tag_size);
 271
 272 int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set)
 273 {
 274         struct bio_integrity_payload *bip = bio->bi_integrity;
 275         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 276         unsigned int nr_sectors;
 277
 278         BUG_ON(bip->bip_buf == NULL);
 279
 280         if (bi->tag_size == 0)
 281                 return -1;
 282
 283         nr_sectors = bio_integrity_hw_sectors(bi,
 284                                         DIV_ROUND_UP(len, bi->tag_size));
 285
 286         if (nr_sectors * bi->tuple_size > bip->bip_size) {
 287                 printk(KERN_ERR "%s: tag too big for bio: %u > %u\n",
 288                        __func__, nr_sectors * bi->tuple_size, bip->bip_size);
 289                 return -1;
 290         }
 291
 292         if (set)
 293                 bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
 294         else
 295                 bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
 296
 297         return 0;
 298 }
 299
 300 /**
 301  * bio_integrity_set_tag - Attach a tag buffer to a bio
 302  * @bio:        bio to attach buffer to
 303  * @tag_buf:    Pointer to a buffer containing tag data
 304  * @len:        Length of the included buffer
 305  *
 306  * Description: Use this function to tag a bio by leveraging the extra
 307  * space provided by devices formatted with integrity protection.  The
 308  * size of the integrity buffer must be <= to the size reported by
 309  * bio_integrity_tag_size().
 310  */
 311 int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len)
 312 {
 313         BUG_ON(bio_data_dir(bio) != WRITE);
 314
 315         return bio_integrity_tag(bio, tag_buf, len, 1);
 316 }
 317 EXPORT_SYMBOL(bio_integrity_set_tag);
 318
 319 /**
 320  * bio_integrity_get_tag - Retrieve a tag buffer from a bio
 321  * @bio:        bio to retrieve buffer from
 322  * @tag_buf:    Pointer to a buffer for the tag data
 323  * @len:        Length of the target buffer
 324  *
 325  * Description: Use this function to retrieve the tag buffer from a
 326  * completed I/O. The size of the integrity buffer must be <= to the
 327  * size reported by bio_integrity_tag_size().
 328  */
 329 int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
 330 {
 331         BUG_ON(bio_data_dir(bio) != READ);
 332
 333         return bio_integrity_tag(bio, tag_buf, len, 0);
 334 }
 335 EXPORT_SYMBOL(bio_integrity_get_tag);
 336
 337 /**
 338  * bio_integrity_generate - Generate integrity metadata for a bio
 339  * @bio:        bio to generate integrity metadata for
 340  *
 341  * Description: Generates integrity metadata for a bio by calling the
 342  * block device's generation callback function.  The bio must have a
 343  * bip attached with enough room to accommodate the generated
 344  * integrity metadata.
 345  */
 346 static void bio_integrity_generate(struct bio *bio)
 347 {
 348         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 349         struct blk_integrity_exchg bix;
 350         struct bio_vec *bv;
 351         sector_t sector = bio->bi_sector;
 352         unsigned int i, sectors, total;
 353         void *prot_buf = bio->bi_integrity->bip_buf;
 354
 355         total = 0;
 356         bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 357         bix.sector_size = bi->sector_size;
 358
 359         bio_for_each_segment(bv, bio, i) {
 360                 void *kaddr = kmap_atomic(bv->bv_page);
 361                 bix.data_buf = kaddr + bv->bv_offset;
 362                 bix.data_size = bv->bv_len;
 363                 bix.prot_buf = prot_buf;
 364                 bix.sector = sector;
 365
 366                 bi->generate_fn(&bix);
 367
 368                 sectors = bv->bv_len / bi->sector_size;
 369                 sector += sectors;
 370                 prot_buf += sectors * bi->tuple_size;
 371                 total += sectors * bi->tuple_size;
 372                 BUG_ON(total > bio->bi_integrity->bip_size);
 373
 374                 kunmap_atomic(kaddr);
 375         }
 376 }
 377
 378 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
 379 {
 380         if (bi)
 381                 return bi->tuple_size;
 382
 383         return 0;
 384 }
 385
 386 /**
 387  * bio_integrity_prep - Prepare bio for integrity I/O
 388  * @bio:        bio to prepare
 389  *
 390  * Description: Allocates a buffer for integrity metadata, maps the
 391  * pages and attaches them to a bio.  The bio must have data
 392  * direction, target device and start sector set priot to calling.  In
 393  * the WRITE case, integrity metadata will be generated using the
 394  * block device's integrity function.  In the READ case, the buffer
 395  * will be prepared for DMA and a suitable end_io handler set up.
 396  */
 397 int bio_integrity_prep(struct bio *bio)
 398 {
 399         struct bio_integrity_payload *bip;
 400         struct blk_integrity *bi;
 401         struct request_queue *q;
 402         void *buf;
 403         unsigned long start, end;
 404         unsigned int len, nr_pages;
 405         unsigned int bytes, offset, i;
 406         unsigned int sectors;
 407
 408         bi = bdev_get_integrity(bio->bi_bdev);
 409         q = bdev_get_queue(bio->bi_bdev);
 410         BUG_ON(bi == NULL);
 411         BUG_ON(bio_integrity(bio));
 412
 413         sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
 414
 415         /* Allocate kernel buffer for protection data */
 416         len = sectors * blk_integrity_tuple_size(bi);
 417         buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
 418         if (unlikely(buf == NULL)) {
 419                 printk(KERN_ERR "could not allocate integrity buffer\n");
 420                 return -ENOMEM;
 421         }
 422
 423         end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 424         start = ((unsigned long) buf) >> PAGE_SHIFT;
 425         nr_pages = end - start;
 426
 427         /* Allocate bio integrity payload and integrity vectors */
 428         bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
 429         if (unlikely(bip == NULL)) {
 430                 printk(KERN_ERR "could not allocate data integrity bioset\n");
 431                 kfree(buf);
 432                 return -EIO;
 433         }
 434
 435         bip->bip_buf = buf;
 436         bip->bip_size = len;
 437         bip->bip_sector = bio->bi_sector;
 438
 439         /* Map it */
 440         offset = offset_in_page(buf);
 441         for (i = 0 ; i < nr_pages ; i++) {
 442                 int ret;
 443                 bytes = PAGE_SIZE - offset;
 444
 445                 if (len <= 0)
 446                         break;
 447
 448                 if (bytes > len)
 449                         bytes = len;
 450
 451                 ret = bio_integrity_add_page(bio, virt_to_page(buf),
 452                                              bytes, offset);
 453
 454                 if (ret == 0)
 455                         return 0;
 456
 457                 if (ret < bytes)
 458                         break;
 459
 460                 buf += bytes;
 461                 len -= bytes;
 462                 offset = 0;
 463         }
 464
 465         /* Install custom I/O completion handler if read verify is enabled */
 466         if (bio_data_dir(bio) == READ) {
 467                 bip->bip_end_io = bio->bi_end_io;
 468                 bio->bi_end_io = bio_integrity_endio;
 469         }
 470
 471         /* Auto-generate integrity metadata if this is a write */
 472         if (bio_data_dir(bio) == WRITE)
 473                 bio_integrity_generate(bio);
 474
 475         return 0;
 476 }
 477 EXPORT_SYMBOL(bio_integrity_prep);
 478
 479 /**
 480  * bio_integrity_verify - Verify integrity metadata for a bio
 481  * @bio:        bio to verify
 482  *
 483  * Description: This function is called to verify the integrity of a
 484  * bio.  The data in the bio io_vec is compared to the integrity
 485  * metadata returned by the HBA.
 486  */
 487 static int bio_integrity_verify(struct bio *bio)
 488 {
 489         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 490         struct blk_integrity_exchg bix;
 491         struct bio_vec *bv;
 492         sector_t sector = bio->bi_integrity->bip_sector;
 493         unsigned int i, sectors, total, ret;
 494         void *prot_buf = bio->bi_integrity->bip_buf;
 495
 496         ret = total = 0;
 497         bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 498         bix.sector_size = bi->sector_size;
 499
 500         bio_for_each_segment(bv, bio, i) {
 501                 void *kaddr = kmap_atomic(bv->bv_page);
 502                 bix.data_buf = kaddr + bv->bv_offset;
 503                 bix.data_size = bv->bv_len;
 504                 bix.prot_buf = prot_buf;
 505                 bix.sector = sector;
 506
 507                 ret = bi->verify_fn(&bix);
 508
 509                 if (ret) {
 510                         kunmap_atomic(kaddr);
 511                         return ret;
 512                 }
 513
 514                 sectors = bv->bv_len / bi->sector_size;
 515                 sector += sectors;
 516                 prot_buf += sectors * bi->tuple_size;
 517                 total += sectors * bi->tuple_size;
 518                 BUG_ON(total > bio->bi_integrity->bip_size);
 519
 520                 kunmap_atomic(kaddr);
 521         }
 522
 523         return ret;
 524 }
 525
 526 /**
 527  * bio_integrity_verify_fn - Integrity I/O completion worker
 528  * @work:       Work struct stored in bio to be verified
 529  *
 530  * Description: This workqueue function is called to complete a READ
 531  * request.  The function verifies the transferred integrity metadata
 532  * and then calls the original bio end_io function.
 533  */
 534 static void bio_integrity_verify_fn(struct work_struct *work)
 535 {
 536         struct bio_integrity_payload *bip =
 537                 container_of(work, struct bio_integrity_payload, bip_work);
 538         struct bio *bio = bip->bip_bio;
 539         int error;
 540
 541         error = bio_integrity_verify(bio);
 542
 543         /* Restore original bio completion handler */
 544         bio->bi_end_io = bip->bip_end_io;
 545         bio_endio(bio, error);
 546 }
 547
 548 /**
 549  * bio_integrity_endio - Integrity I/O completion function
 550  * @bio:        Protected bio
 551  * @error:      Pointer to errno
 552  *
 553  * Description: Completion for integrity I/O
 554  *
 555  * Normally I/O completion is done in interrupt context.  However,
 556  * verifying I/O integrity is a time-consuming task which must be run
 557  * in process context.  This function postpones completion
 558  * accordingly.
 559  */
 560 void bio_integrity_endio(struct bio *bio, int error)
 561 {
 562         struct bio_integrity_payload *bip = bio->bi_integrity;
 563
 564         BUG_ON(bip->bip_bio != bio);
 565
 566         /* In case of an I/O error there is no point in verifying the
 567          * integrity metadata.  Restore original bio end_io handler
 568          * and run it.
 569          */
 570         if (error) {
 571                 bio->bi_end_io = bip->bip_end_io;
 572                 bio_endio(bio, error);
 573
 574                 return;
 575         }
 576
 577         INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 578         queue_work(kintegrityd_wq, &bip->bip_work);
 579 }
 580 EXPORT_SYMBOL(bio_integrity_endio);
 581
 582 /**
 583  * bio_integrity_mark_head - Advance bip_vec skip bytes
 584  * @bip:        Integrity vector to advance
 585  * @skip:       Number of bytes to advance it
 586  */
 587 void bio_integrity_mark_head(struct bio_integrity_payload *bip,
 588                              unsigned int skip)
 589 {
 590         struct bio_vec *iv;
 591         unsigned int i;
 592
 593         bip_for_each_vec(iv, bip, i) {
 594                 if (skip == 0) {
 595                         bip->bip_idx = i;
 596                         return;
 597                 } else if (skip >= iv->bv_len) {
 598                         skip -= iv->bv_len;
 599                 } else { /* skip < iv->bv_len) */
 600                         iv->bv_offset += skip;
 601                         iv->bv_len -= skip;
 602                         bip->bip_idx = i;
 603                         return;
 604                 }
 605         }
 606 }
 607
 608 /**
 609  * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long
 610  * @bip:        Integrity vector to truncate
 611  * @len:        New length of integrity vector
 612  */
 613 void bio_integrity_mark_tail(struct bio_integrity_payload *bip,
 614                              unsigned int len)
 615 {
 616         struct bio_vec *iv;
 617         unsigned int i;
 618
 619         bip_for_each_vec(iv, bip, i) {
 620                 if (len == 0) {
 621                         bip->bip_vcnt = i;
 622                         return;
 623                 } else if (len >= iv->bv_len) {
 624                         len -= iv->bv_len;
 625                 } else { /* len < iv->bv_len) */
 626                         iv->bv_len = len;
 627                         len = 0;
 628                 }
 629         }
 630 }
 631
 632 /**
 633  * bio_integrity_advance - Advance integrity vector
 634  * @bio:        bio whose integrity vector to update
 635  * @bytes_done: number of data bytes that have been completed
 636  *
 637  * Description: This function calculates how many integrity bytes the
 638  * number of completed data bytes correspond to and advances the
 639  * integrity vector accordingly.
 640  */
 641 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 642 {
 643         struct bio_integrity_payload *bip = bio->bi_integrity;
 644         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 645         unsigned int nr_sectors;
 646
 647         BUG_ON(bip == NULL);
 648         BUG_ON(bi == NULL);
 649
 650         nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9);
 651         bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size);
 652 }
 653 EXPORT_SYMBOL(bio_integrity_advance);
 654
 655 /**
 656  * bio_integrity_trim - Trim integrity vector
 657  * @bio:        bio whose integrity vector to update
 658  * @offset:     offset to first data sector
 659  * @sectors:    number of data sectors
 660  *
 661  * Description: Used to trim the integrity vector in a cloned bio.
 662  * The ivec will be advanced corresponding to 'offset' data sectors
 663  * and the length will be truncated corresponding to 'len' data
 664  * sectors.
 665  */
 666 void bio_integrity_trim(struct bio *bio, unsigned int offset,
 667                         unsigned int sectors)
 668 {
 669         struct bio_integrity_payload *bip = bio->bi_integrity;
 670         struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 671         unsigned int nr_sectors;
 672
 673         BUG_ON(bip == NULL);
 674         BUG_ON(bi == NULL);
 675         BUG_ON(!bio_flagged(bio, BIO_CLONED));
 676
 677         nr_sectors = bio_integrity_hw_sectors(bi, sectors);
 678         bip->bip_sector = bip->bip_sector + offset;
 679         bio_integrity_mark_head(bip, offset * bi->tuple_size);
 680         bio_integrity_mark_tail(bip, sectors * bi->tuple_size);
 681 }
 682 EXPORT_SYMBOL(bio_integrity_trim);
 683
 684 /**
 685  * bio_integrity_split - Split integrity metadata
 686  * @bio:        Protected bio
 687  * @bp:         Resulting bio_pair
 688  * @sectors:    Offset
 689  *
 690  * Description: Splits an integrity page into a bio_pair.
 691  */
 692 void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
 693 {
 694         struct blk_integrity *bi;
 695         struct bio_integrity_payload *bip = bio->bi_integrity;
 696         unsigned int nr_sectors;
 697
 698         if (bio_integrity(bio) == 0)
 699                 return;
 700
 701         bi = bdev_get_integrity(bio->bi_bdev);
 702         BUG_ON(bi == NULL);
 703         BUG_ON(bip->bip_vcnt != 1);
 704
 705         nr_sectors = bio_integrity_hw_sectors(bi, sectors);
 706
 707         bp->bio1.bi_integrity = &bp->bip1;
 708         bp->bio2.bi_integrity = &bp->bip2;
 709
 710         bp->iv1 = bip->bip_vec[0];
 711         bp->iv2 = bip->bip_vec[0];
 712
 713         bp->bip1.bip_vec[0] = bp->iv1;
 714         bp->bip2.bip_vec[0] = bp->iv2;
 715
 716         bp->iv1.bv_len = sectors * bi->tuple_size;
 717         bp->iv2.bv_offset += sectors * bi->tuple_size;
 718         bp->iv2.bv_len -= sectors * bi->tuple_size;
 719
 720         bp->bip1.bip_sector = bio->bi_integrity->bip_sector;
 721         bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors;
 722
 723         bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1;
 724         bp->bip1.bip_idx = bp->bip2.bip_idx = 0;
 725 }
 726 EXPORT_SYMBOL(bio_integrity_split);
 727
 728 /**
 729  * bio_integrity_clone - Callback for cloning bios with integrity metadata
 730  * @bio:        New bio
 731  * @bio_src:    Original bio
 732  * @gfp_mask:   Memory allocation mask
 733  * @bs:         bio_set to allocate bip from
 734  *
 735  * Description: Called to allocate a bip when cloning a bio
 736  */
 737 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 738                         gfp_t gfp_mask, struct bio_set *bs)
 739 {
 740         struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
 741         struct bio_integrity_payload *bip;
 742
 743         BUG_ON(bip_src == NULL);
 744
 745         bip = bio_integrity_alloc_bioset(bio, gfp_mask, bip_src->bip_vcnt, bs);
 746
 747         if (bip == NULL)
 748                 return -EIO;
 749
 750         memcpy(bip->bip_vec, bip_src->bip_vec,
 751                bip_src->bip_vcnt * sizeof(struct bio_vec));
 752
 753         bip->bip_sector = bip_src->bip_sector;
 754         bip->bip_vcnt = bip_src->bip_vcnt;
 755         bip->bip_idx = bip_src->bip_idx;
 756
 757         return 0;
 758 }
 759 EXPORT_SYMBOL(bio_integrity_clone);
 760
 761 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 762 {
 763         unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
 764
 765         if (bs->bio_integrity_pool)
 766                 return 0;
 767
 768         bs->bio_integrity_pool =
 769                 mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
 770
 771         if (!bs->bio_integrity_pool)
 772                 return -1;
 773
 774         return 0;
 775 }
 776 EXPORT_SYMBOL(bioset_integrity_create);
 777
 778 void bioset_integrity_free(struct bio_set *bs)
 779 {
 780         if (bs->bio_integrity_pool)
 781                 mempool_destroy(bs->bio_integrity_pool);
 782 }
 783 EXPORT_SYMBOL(bioset_integrity_free);
 784
 785 void __init bio_integrity_init(void)
 786 {
 787         unsigned int i;
 788
 789         /*
 790          * kintegrityd won't block much but may burn a lot of CPU cycles.
 791          * Make it highpri CPU intensive wq with max concurrency of 1.
 792          */
 793         kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
 794                                          WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
 795         if (!kintegrityd_wq)
 796                 panic("Failed to create kintegrityd\n");
 797
 798         for (i = 0 ; i < BIOVEC_NR_POOLS ; i++) {
 799                 unsigned int size;
 800
 801                 size = sizeof(struct bio_integrity_payload)
 802                         + bip_slab[i].nr_vecs * sizeof(struct bio_vec);
 803
 804                 bip_slab[i].slab =
 805                         kmem_cache_create(bip_slab[i].name, size, 0,
 806                                           SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 807         }
 808 }