block/bio-integrity.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * bio-integrity.c - bio data integrity extensions
   4  *
   5  * Copyright (C) 2007, 2008, 2009 Oracle Corporation
   6  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
   7  */
   8
   9 #include <linux/blk-integrity.h>
  10 #include <linux/mempool.h>
  11 #include <linux/export.h>
  12 #include <linux/bio.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/slab.h>
  15 #include "blk.h"
  16
  17 static struct kmem_cache *bip_slab;
  18 static struct workqueue_struct *kintegrityd_wq;
  19
  20 void blk_flush_integrity(void)
  21 {
  22         flush_workqueue(kintegrityd_wq);
  23 }
  24
  25 /**
  26  * bio_integrity_free - Free bio integrity payload
  27  * @bio:        bio containing bip to be freed
  28  *
  29  * Description: Free the integrity portion of a bio.
  30  */
  31 void bio_integrity_free(struct bio *bio)
  32 {
  33         struct bio_integrity_payload *bip = bio_integrity(bio);
  34         struct bio_set *bs = bio->bi_pool;
  35
  36         if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
  37                 if (bip->bip_vec)
  38                         bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
  39                                   bip->bip_max_vcnt);
  40                 mempool_free(bip, &bs->bio_integrity_pool);
  41         } else {
  42                 kfree(bip);
  43         }
  44         bio->bi_integrity = NULL;
  45         bio->bi_opf &= ~REQ_INTEGRITY;
  46 }
  47
  48 /**
  49  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
  50  * @bio:        bio to attach integrity metadata to
  51  * @gfp_mask:   Memory allocation mask
  52  * @nr_vecs:    Number of integrity metadata scatter-gather elements
  53  *
  54  * Description: This function prepares a bio for attaching integrity
  55  * metadata.  nr_vecs specifies the maximum number of pages containing
  56  * integrity metadata that can be attached.
  57  */
  58 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
  59                                                   gfp_t gfp_mask,
  60                                                   unsigned int nr_vecs)
  61 {
  62         struct bio_integrity_payload *bip;
  63         struct bio_set *bs = bio->bi_pool;
  64         unsigned inline_vecs;
  65
  66         if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
  67                 return ERR_PTR(-EOPNOTSUPP);
  68
  69         if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
  70                 bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
  71                 inline_vecs = nr_vecs;
  72         } else {
  73                 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
  74                 inline_vecs = BIO_INLINE_VECS;
  75         }
  76
  77         if (unlikely(!bip))
  78                 return ERR_PTR(-ENOMEM);
  79
  80         memset(bip, 0, sizeof(*bip));
  81
  82         /* always report as many vecs as asked explicitly, not inline vecs */
  83         bip->bip_max_vcnt = nr_vecs;
  84         if (nr_vecs > inline_vecs) {
  85                 bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
  86                                           &bip->bip_max_vcnt, gfp_mask);
  87                 if (!bip->bip_vec)
  88                         goto err;
  89         } else if (nr_vecs) {
  90                 bip->bip_vec = bip->bip_inline_vecs;
  91         }
  92
  93         bip->bip_bio = bio;
  94         bio->bi_integrity = bip;
  95         bio->bi_opf |= REQ_INTEGRITY;
  96
  97         return bip;
  98 err:
  99         if (bs && mempool_initialized(&bs->bio_integrity_pool))
 100                 mempool_free(bip, &bs->bio_integrity_pool);
 101         else
 102                 kfree(bip);
 103         return ERR_PTR(-ENOMEM);
 104 }
 105 EXPORT_SYMBOL(bio_integrity_alloc);
 106
 107 static void bio_integrity_unpin_bvec(struct bio_vec *bv, int nr_vecs,
 108                                      bool dirty)
 109 {
 110         int i;
 111
 112         for (i = 0; i < nr_vecs; i++) {
 113                 if (dirty && !PageCompound(bv[i].bv_page))
 114                         set_page_dirty_lock(bv[i].bv_page);
 115                 unpin_user_page(bv[i].bv_page);
 116         }
 117 }
 118
 119 static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
 120 {
 121         unsigned short nr_vecs = bip->bip_max_vcnt - 1;
 122         struct bio_vec *copy = &bip->bip_vec[1];
 123         size_t bytes = bip->bip_iter.bi_size;
 124         struct iov_iter iter;
 125         int ret;
 126
 127         iov_iter_bvec(&iter, ITER_DEST, copy, nr_vecs, bytes);
 128         ret = copy_to_iter(bvec_virt(bip->bip_vec), bytes, &iter);
 129         WARN_ON_ONCE(ret != bytes);
 130
 131         bio_integrity_unpin_bvec(copy, nr_vecs, true);
 132 }
 133
 134 /**
 135  * bio_integrity_unmap_user - Unmap user integrity payload
 136  * @bio:        bio containing bip to be unmapped
 137  *
 138  * Unmap the user mapped integrity portion of a bio.
 139  */
 140 void bio_integrity_unmap_user(struct bio *bio)
 141 {
 142         struct bio_integrity_payload *bip = bio_integrity(bio);
 143
 144         if (bip->bip_flags & BIP_COPY_USER) {
 145                 if (bio_data_dir(bio) == READ)
 146                         bio_integrity_uncopy_user(bip);
 147                 kfree(bvec_virt(bip->bip_vec));
 148                 return;
 149         }
 150
 151         bio_integrity_unpin_bvec(bip->bip_vec, bip->bip_max_vcnt,
 152                         bio_data_dir(bio) == READ);
 153 }
 154
 155 /**
 156  * bio_integrity_add_page - Attach integrity metadata
 157  * @bio:        bio to update
 158  * @page:       page containing integrity metadata
 159  * @len:        number of bytes of integrity metadata in page
 160  * @offset:     start offset within page
 161  *
 162  * Description: Attach a page containing integrity metadata to bio.
 163  */
 164 int bio_integrity_add_page(struct bio *bio, struct page *page,
 165                            unsigned int len, unsigned int offset)
 166 {
 167         struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 168         struct bio_integrity_payload *bip = bio_integrity(bio);
 169
 170         if (bip->bip_vcnt > 0) {
 171                 struct bio_vec *bv = &bip->bip_vec[bip->bip_vcnt - 1];
 172                 bool same_page = false;
 173
 174                 if (bvec_try_merge_hw_page(q, bv, page, len, offset,
 175                                            &same_page)) {
 176                         bip->bip_iter.bi_size += len;
 177                         return len;
 178                 }
 179
 180                 if (bip->bip_vcnt >=
 181                     min(bip->bip_max_vcnt, queue_max_integrity_segments(q)))
 182                         return 0;
 183
 184                 /*
 185                  * If the queue doesn't support SG gaps and adding this segment
 186                  * would create a gap, disallow it.
 187                  */
 188                 if (bvec_gap_to_prev(&q->limits, bv, offset))
 189                         return 0;
 190         }
 191
 192         bvec_set_page(&bip->bip_vec[bip->bip_vcnt], page, len, offset);
 193         bip->bip_vcnt++;
 194         bip->bip_iter.bi_size += len;
 195
 196         return len;
 197 }
 198 EXPORT_SYMBOL(bio_integrity_add_page);
 199
 200 static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
 201                                    int nr_vecs, unsigned int len,
 202                                    unsigned int direction)
 203 {
 204         bool write = direction == ITER_SOURCE;
 205         struct bio_integrity_payload *bip;
 206         struct iov_iter iter;
 207         void *buf;
 208         int ret;
 209
 210         buf = kmalloc(len, GFP_KERNEL);
 211         if (!buf)
 212                 return -ENOMEM;
 213
 214         if (write) {
 215                 iov_iter_bvec(&iter, direction, bvec, nr_vecs, len);
 216                 if (!copy_from_iter_full(buf, len, &iter)) {
 217                         ret = -EFAULT;
 218                         goto free_buf;
 219                 }
 220
 221                 bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
 222         } else {
 223                 memset(buf, 0, len);
 224
 225                 /*
 226                  * We need to preserve the original bvec and the number of vecs
 227                  * in it for completion handling
 228                  */
 229                 bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs + 1);
 230         }
 231
 232         if (IS_ERR(bip)) {
 233                 ret = PTR_ERR(bip);
 234                 goto free_buf;
 235         }
 236
 237         if (write)
 238                 bio_integrity_unpin_bvec(bvec, nr_vecs, false);
 239         else
 240                 memcpy(&bip->bip_vec[1], bvec, nr_vecs * sizeof(*bvec));
 241
 242         ret = bio_integrity_add_page(bio, virt_to_page(buf), len,
 243                                      offset_in_page(buf));
 244         if (ret != len) {
 245                 ret = -ENOMEM;
 246                 goto free_bip;
 247         }
 248
 249         bip->bip_flags |= BIP_COPY_USER;
 250         bip->bip_vcnt = nr_vecs;
 251         return 0;
 252 free_bip:
 253         bio_integrity_free(bio);
 254 free_buf:
 255         kfree(buf);
 256         return ret;
 257 }
 258
 259 static int bio_integrity_init_user(struct bio *bio, struct bio_vec *bvec,
 260                                    int nr_vecs, unsigned int len)
 261 {
 262         struct bio_integrity_payload *bip;
 263
 264         bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs);
 265         if (IS_ERR(bip))
 266                 return PTR_ERR(bip);
 267
 268         memcpy(bip->bip_vec, bvec, nr_vecs * sizeof(*bvec));
 269         bip->bip_iter.bi_size = len;
 270         bip->bip_vcnt = nr_vecs;
 271         return 0;
 272 }
 273
 274 static unsigned int bvec_from_pages(struct bio_vec *bvec, struct page **pages,
 275                                     int nr_vecs, ssize_t bytes, ssize_t offset)
 276 {
 277         unsigned int nr_bvecs = 0;
 278         int i, j;
 279
 280         for (i = 0; i < nr_vecs; i = j) {
 281                 size_t size = min_t(size_t, bytes, PAGE_SIZE - offset);
 282                 struct folio *folio = page_folio(pages[i]);
 283
 284                 bytes -= size;
 285                 for (j = i + 1; j < nr_vecs; j++) {
 286                         size_t next = min_t(size_t, PAGE_SIZE, bytes);
 287
 288                         if (page_folio(pages[j]) != folio ||
 289                             pages[j] != pages[j - 1] + 1)
 290                                 break;
 291                         unpin_user_page(pages[j]);
 292                         size += next;
 293                         bytes -= next;
 294                 }
 295
 296                 bvec_set_page(&bvec[nr_bvecs], pages[i], size, offset);
 297                 offset = 0;
 298                 nr_bvecs++;
 299         }
 300
 301         return nr_bvecs;
 302 }
 303
 304 int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t bytes)
 305 {
 306         struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 307         unsigned int align = blk_lim_dma_alignment_and_pad(&q->limits);
 308         struct page *stack_pages[UIO_FASTIOV], **pages = stack_pages;
 309         struct bio_vec stack_vec[UIO_FASTIOV], *bvec = stack_vec;
 310         unsigned int direction, nr_bvecs;
 311         struct iov_iter iter;
 312         int ret, nr_vecs;
 313         size_t offset;
 314         bool copy;
 315
 316         if (bio_integrity(bio))
 317                 return -EINVAL;
 318         if (bytes >> SECTOR_SHIFT > queue_max_hw_sectors(q))
 319                 return -E2BIG;
 320
 321         if (bio_data_dir(bio) == READ)
 322                 direction = ITER_DEST;
 323         else
 324                 direction = ITER_SOURCE;
 325
 326         iov_iter_ubuf(&iter, direction, ubuf, bytes);
 327         nr_vecs = iov_iter_npages(&iter, BIO_MAX_VECS + 1);
 328         if (nr_vecs > BIO_MAX_VECS)
 329                 return -E2BIG;
 330         if (nr_vecs > UIO_FASTIOV) {
 331                 bvec = kcalloc(nr_vecs, sizeof(*bvec), GFP_KERNEL);
 332                 if (!bvec)
 333                         return -ENOMEM;
 334                 pages = NULL;
 335         }
 336
 337         copy = !iov_iter_is_aligned(&iter, align, align);
 338         ret = iov_iter_extract_pages(&iter, &pages, bytes, nr_vecs, 0, &offset);
 339         if (unlikely(ret < 0))
 340                 goto free_bvec;
 341
 342         nr_bvecs = bvec_from_pages(bvec, pages, nr_vecs, bytes, offset);
 343         if (pages != stack_pages)
 344                 kvfree(pages);
 345         if (nr_bvecs > queue_max_integrity_segments(q))
 346                 copy = true;
 347
 348         if (copy)
 349                 ret = bio_integrity_copy_user(bio, bvec, nr_bvecs, bytes,
 350                                               direction);
 351         else
 352                 ret = bio_integrity_init_user(bio, bvec, nr_bvecs, bytes);
 353         if (ret)
 354                 goto release_pages;
 355         if (bvec != stack_vec)
 356                 kfree(bvec);
 357
 358         return 0;
 359
 360 release_pages:
 361         bio_integrity_unpin_bvec(bvec, nr_bvecs, false);
 362 free_bvec:
 363         if (bvec != stack_vec)
 364                 kfree(bvec);
 365         return ret;
 366 }
 367
 368 /**
 369  * bio_integrity_prep - Prepare bio for integrity I/O
 370  * @bio:        bio to prepare
 371  *
 372  * Description:  Checks if the bio already has an integrity payload attached.
 373  * If it does, the payload has been generated by another kernel subsystem,
 374  * and we just pass it through. Otherwise allocates integrity payload.
 375  * The bio must have data direction, target device and start sector set priot
 376  * to calling.  In the WRITE case, integrity metadata will be generated using
 377  * the block device's integrity function.  In the READ case, the buffer
 378  * will be prepared for DMA and a suitable end_io handler set up.
 379  */
 380 bool bio_integrity_prep(struct bio *bio)
 381 {
 382         struct bio_integrity_payload *bip;
 383         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 384         unsigned int len;
 385         void *buf;
 386         gfp_t gfp = GFP_NOIO;
 387
 388         if (!bi)
 389                 return true;
 390
 391         if (!bio_sectors(bio))
 392                 return true;
 393
 394         /* Already protected? */
 395         if (bio_integrity(bio))
 396                 return true;
 397
 398         switch (bio_op(bio)) {
 399         case REQ_OP_READ:
 400                 if (bi->flags & BLK_INTEGRITY_NOVERIFY)
 401                         return true;
 402                 break;
 403         case REQ_OP_WRITE:
 404                 if (bi->flags & BLK_INTEGRITY_NOGENERATE)
 405                         return true;
 406
 407                 /*
 408                  * Zero the memory allocated to not leak uninitialized kernel
 409                  * memory to disk for non-integrity metadata where nothing else
 410                  * initializes the memory.
 411                  */
 412                 if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE)
 413                         gfp |= __GFP_ZERO;
 414                 break;
 415         default:
 416                 return true;
 417         }
 418
 419         /* Allocate kernel buffer for protection data */
 420         len = bio_integrity_bytes(bi, bio_sectors(bio));
 421         buf = kmalloc(len, gfp);
 422         if (unlikely(buf == NULL)) {
 423                 goto err_end_io;
 424         }
 425
 426         bip = bio_integrity_alloc(bio, GFP_NOIO, 1);
 427         if (IS_ERR(bip)) {
 428                 kfree(buf);
 429                 goto err_end_io;
 430         }
 431
 432         bip->bip_flags |= BIP_BLOCK_INTEGRITY;
 433         bip_set_seed(bip, bio->bi_iter.bi_sector);
 434
 435         if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
 436                 bip->bip_flags |= BIP_IP_CHECKSUM;
 437
 438         if (bio_integrity_add_page(bio, virt_to_page(buf), len,
 439                         offset_in_page(buf)) < len) {
 440                 printk(KERN_ERR "could not attach integrity payload\n");
 441                 goto err_end_io;
 442         }
 443
 444         /* Auto-generate integrity metadata if this is a write */
 445         if (bio_data_dir(bio) == WRITE)
 446                 blk_integrity_generate(bio);
 447         else
 448                 bip->bio_iter = bio->bi_iter;
 449         return true;
 450
 451 err_end_io:
 452         bio->bi_status = BLK_STS_RESOURCE;
 453         bio_endio(bio);
 454         return false;
 455 }
 456 EXPORT_SYMBOL(bio_integrity_prep);
 457
 458 /**
 459  * bio_integrity_verify_fn - Integrity I/O completion worker
 460  * @work:       Work struct stored in bio to be verified
 461  *
 462  * Description: This workqueue function is called to complete a READ
 463  * request.  The function verifies the transferred integrity metadata
 464  * and then calls the original bio end_io function.
 465  */
 466 static void bio_integrity_verify_fn(struct work_struct *work)
 467 {
 468         struct bio_integrity_payload *bip =
 469                 container_of(work, struct bio_integrity_payload, bip_work);
 470         struct bio *bio = bip->bip_bio;
 471
 472         blk_integrity_verify(bio);
 473
 474         kfree(bvec_virt(bip->bip_vec));
 475         bio_integrity_free(bio);
 476         bio_endio(bio);
 477 }
 478
 479 /**
 480  * __bio_integrity_endio - Integrity I/O completion function
 481  * @bio:        Protected bio
 482  *
 483  * Description: Completion for integrity I/O
 484  *
 485  * Normally I/O completion is done in interrupt context.  However,
 486  * verifying I/O integrity is a time-consuming task which must be run
 487  * in process context.  This function postpones completion
 488  * accordingly.
 489  */
 490 bool __bio_integrity_endio(struct bio *bio)
 491 {
 492         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 493         struct bio_integrity_payload *bip = bio_integrity(bio);
 494
 495         if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && bi->csum_type) {
 496                 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 497                 queue_work(kintegrityd_wq, &bip->bip_work);
 498                 return false;
 499         }
 500
 501         kfree(bvec_virt(bip->bip_vec));
 502         bio_integrity_free(bio);
 503         return true;
 504 }
 505
 506 /**
 507  * bio_integrity_advance - Advance integrity vector
 508  * @bio:        bio whose integrity vector to update
 509  * @bytes_done: number of data bytes that have been completed
 510  *
 511  * Description: This function calculates how many integrity bytes the
 512  * number of completed data bytes correspond to and advances the
 513  * integrity vector accordingly.
 514  */
 515 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 516 {
 517         struct bio_integrity_payload *bip = bio_integrity(bio);
 518         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 519         unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 520
 521         bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
 522         bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
 523 }
 524
 525 /**
 526  * bio_integrity_trim - Trim integrity vector
 527  * @bio:        bio whose integrity vector to update
 528  *
 529  * Description: Used to trim the integrity vector in a cloned bio.
 530  */
 531 void bio_integrity_trim(struct bio *bio)
 532 {
 533         struct bio_integrity_payload *bip = bio_integrity(bio);
 534         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 535
 536         bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 537 }
 538 EXPORT_SYMBOL(bio_integrity_trim);
 539
 540 /**
 541  * bio_integrity_clone - Callback for cloning bios with integrity metadata
 542  * @bio:        New bio
 543  * @bio_src:    Original bio
 544  * @gfp_mask:   Memory allocation mask
 545  *
 546  * Description: Called to allocate a bip when cloning a bio
 547  */
 548 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 549                         gfp_t gfp_mask)
 550 {
 551         struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
 552         struct bio_integrity_payload *bip;
 553
 554         BUG_ON(bip_src == NULL);
 555
 556         bip = bio_integrity_alloc(bio, gfp_mask, 0);
 557         if (IS_ERR(bip))
 558                 return PTR_ERR(bip);
 559
 560         bip->bip_vec = bip_src->bip_vec;
 561         bip->bip_iter = bip_src->bip_iter;
 562         bip->bip_flags = bip_src->bip_flags & ~BIP_BLOCK_INTEGRITY;
 563
 564         return 0;
 565 }
 566
 567 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 568 {
 569         if (mempool_initialized(&bs->bio_integrity_pool))
 570                 return 0;
 571
 572         if (mempool_init_slab_pool(&bs->bio_integrity_pool,
 573                                    pool_size, bip_slab))
 574                 return -1;
 575
 576         if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
 577                 mempool_exit(&bs->bio_integrity_pool);
 578                 return -1;
 579         }
 580
 581         return 0;
 582 }
 583 EXPORT_SYMBOL(bioset_integrity_create);
 584
 585 void bioset_integrity_free(struct bio_set *bs)
 586 {
 587         mempool_exit(&bs->bio_integrity_pool);
 588         mempool_exit(&bs->bvec_integrity_pool);
 589 }
 590
 591 void __init bio_integrity_init(void)
 592 {
 593         /*
 594          * kintegrityd won't block much but may burn a lot of CPU cycles.
 595          * Make it highpri CPU intensive wq with max concurrency of 1.
 596          */
 597         kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
 598                                          WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
 599         if (!kintegrityd_wq)
 600                 panic("Failed to create kintegrityd\n");
 601
 602         bip_slab = kmem_cache_create("bio_integrity_payload",
 603                                      sizeof(struct bio_integrity_payload) +
 604                                      sizeof(struct bio_vec) * BIO_INLINE_VECS,
 605                                      0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 606 }