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