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