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/blkdev.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 #define BIP_INLINE_VECS 4
  18
  19 static struct kmem_cache *bip_slab;
  20 static struct workqueue_struct *kintegrityd_wq;
  21
  22 void blk_flush_integrity(void)
  23 {
  24         flush_workqueue(kintegrityd_wq);
  25 }
  26
  27 void __bio_integrity_free(struct bio_set *bs, struct bio_integrity_payload *bip)
  28 {
  29         if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
  30                 if (bip->bip_vec)
  31                         bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
  32                                   bip->bip_slab);
  33                 mempool_free(bip, &bs->bio_integrity_pool);
  34         } else {
  35                 kfree(bip);
  36         }
  37 }
  38
  39 /**
  40  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
  41  * @bio:        bio to attach integrity metadata to
  42  * @gfp_mask:   Memory allocation mask
  43  * @nr_vecs:    Number of integrity metadata scatter-gather elements
  44  *
  45  * Description: This function prepares a bio for attaching integrity
  46  * metadata.  nr_vecs specifies the maximum number of pages containing
  47  * integrity metadata that can be attached.
  48  */
  49 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
  50                                                   gfp_t gfp_mask,
  51                                                   unsigned int nr_vecs)
  52 {
  53         struct bio_integrity_payload *bip;
  54         struct bio_set *bs = bio->bi_pool;
  55         unsigned inline_vecs;
  56
  57         if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
  58                 return ERR_PTR(-EOPNOTSUPP);
  59
  60         if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
  61                 bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
  62                 inline_vecs = nr_vecs;
  63         } else {
  64                 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
  65                 inline_vecs = BIP_INLINE_VECS;
  66         }
  67
  68         if (unlikely(!bip))
  69                 return ERR_PTR(-ENOMEM);
  70
  71         memset(bip, 0, sizeof(*bip));
  72
  73         if (nr_vecs > inline_vecs) {
  74                 unsigned long idx = 0;
  75
  76                 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
  77                                           &bs->bvec_integrity_pool);
  78                 if (!bip->bip_vec)
  79                         goto err;
  80                 bip->bip_max_vcnt = bvec_nr_vecs(idx);
  81                 bip->bip_slab = idx;
  82         } else {
  83                 bip->bip_vec = bip->bip_inline_vecs;
  84                 bip->bip_max_vcnt = inline_vecs;
  85         }
  86
  87         bip->bip_bio = bio;
  88         bio->bi_integrity = bip;
  89         bio->bi_opf |= REQ_INTEGRITY;
  90
  91         return bip;
  92 err:
  93         __bio_integrity_free(bs, bip);
  94         return ERR_PTR(-ENOMEM);
  95 }
  96 EXPORT_SYMBOL(bio_integrity_alloc);
  97
  98 /**
  99  * bio_integrity_free - Free bio integrity payload
 100  * @bio:        bio containing bip to be freed
 101  *
 102  * Description: Used to free the integrity portion of a bio. Usually
 103  * called from bio_free().
 104  */
 105 void bio_integrity_free(struct bio *bio)
 106 {
 107         struct bio_integrity_payload *bip = bio_integrity(bio);
 108         struct bio_set *bs = bio->bi_pool;
 109
 110         if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
 111                 kfree(page_address(bip->bip_vec->bv_page) +
 112                       bip->bip_vec->bv_offset);
 113
 114         __bio_integrity_free(bs, bip);
 115         bio->bi_integrity = NULL;
 116         bio->bi_opf &= ~REQ_INTEGRITY;
 117 }
 118
 119 /**
 120  * bio_integrity_add_page - Attach integrity metadata
 121  * @bio:        bio to update
 122  * @page:       page containing integrity metadata
 123  * @len:        number of bytes of integrity metadata in page
 124  * @offset:     start offset within page
 125  *
 126  * Description: Attach a page containing integrity metadata to bio.
 127  */
 128 int bio_integrity_add_page(struct bio *bio, struct page *page,
 129                            unsigned int len, unsigned int offset)
 130 {
 131         struct bio_integrity_payload *bip = bio_integrity(bio);
 132         struct bio_vec *iv;
 133
 134         if (bip->bip_vcnt >= bip->bip_max_vcnt) {
 135                 printk(KERN_ERR "%s: bip_vec full\n", __func__);
 136                 return 0;
 137         }
 138
 139         iv = bip->bip_vec + bip->bip_vcnt;
 140
 141         if (bip->bip_vcnt &&
 142             bvec_gap_to_prev(bio->bi_disk->queue,
 143                              &bip->bip_vec[bip->bip_vcnt - 1], offset))
 144                 return 0;
 145
 146         iv->bv_page = page;
 147         iv->bv_len = len;
 148         iv->bv_offset = offset;
 149         bip->bip_vcnt++;
 150
 151         return len;
 152 }
 153 EXPORT_SYMBOL(bio_integrity_add_page);
 154
 155 /**
 156  * bio_integrity_process - Process integrity metadata for a bio
 157  * @bio:        bio to generate/verify integrity metadata for
 158  * @proc_iter:  iterator to process
 159  * @proc_fn:    Pointer to the relevant processing function
 160  */
 161 static blk_status_t bio_integrity_process(struct bio *bio,
 162                 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
 163 {
 164         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 165         struct blk_integrity_iter iter;
 166         struct bvec_iter bviter;
 167         struct bio_vec bv;
 168         struct bio_integrity_payload *bip = bio_integrity(bio);
 169         blk_status_t ret = BLK_STS_OK;
 170         void *prot_buf = page_address(bip->bip_vec->bv_page) +
 171                 bip->bip_vec->bv_offset;
 172
 173         iter.disk_name = bio->bi_disk->disk_name;
 174         iter.interval = 1 << bi->interval_exp;
 175         iter.seed = proc_iter->bi_sector;
 176         iter.prot_buf = prot_buf;
 177
 178         __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
 179                 void *kaddr = kmap_atomic(bv.bv_page);
 180
 181                 iter.data_buf = kaddr + bv.bv_offset;
 182                 iter.data_size = bv.bv_len;
 183
 184                 ret = proc_fn(&iter);
 185                 if (ret) {
 186                         kunmap_atomic(kaddr);
 187                         return ret;
 188                 }
 189
 190                 kunmap_atomic(kaddr);
 191         }
 192         return ret;
 193 }
 194
 195 /**
 196  * bio_integrity_prep - Prepare bio for integrity I/O
 197  * @bio:        bio to prepare
 198  *
 199  * Description:  Checks if the bio already has an integrity payload attached.
 200  * If it does, the payload has been generated by another kernel subsystem,
 201  * and we just pass it through. Otherwise allocates integrity payload.
 202  * The bio must have data direction, target device and start sector set priot
 203  * to calling.  In the WRITE case, integrity metadata will be generated using
 204  * the block device's integrity function.  In the READ case, the buffer
 205  * will be prepared for DMA and a suitable end_io handler set up.
 206  */
 207 bool bio_integrity_prep(struct bio *bio)
 208 {
 209         struct bio_integrity_payload *bip;
 210         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 211         struct request_queue *q = bio->bi_disk->queue;
 212         void *buf;
 213         unsigned long start, end;
 214         unsigned int len, nr_pages;
 215         unsigned int bytes, offset, i;
 216         unsigned int intervals;
 217         blk_status_t status;
 218
 219         if (!bi)
 220                 return true;
 221
 222         if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
 223                 return true;
 224
 225         if (!bio_sectors(bio))
 226                 return true;
 227
 228         /* Already protected? */
 229         if (bio_integrity(bio))
 230                 return true;
 231
 232         if (bio_data_dir(bio) == READ) {
 233                 if (!bi->profile->verify_fn ||
 234                     !(bi->flags & BLK_INTEGRITY_VERIFY))
 235                         return true;
 236         } else {
 237                 if (!bi->profile->generate_fn ||
 238                     !(bi->flags & BLK_INTEGRITY_GENERATE))
 239                         return true;
 240         }
 241         intervals = bio_integrity_intervals(bi, bio_sectors(bio));
 242
 243         /* Allocate kernel buffer for protection data */
 244         len = intervals * bi->tuple_size;
 245         buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
 246         status = BLK_STS_RESOURCE;
 247         if (unlikely(buf == NULL)) {
 248                 printk(KERN_ERR "could not allocate integrity buffer\n");
 249                 goto err_end_io;
 250         }
 251
 252         end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 253         start = ((unsigned long) buf) >> PAGE_SHIFT;
 254         nr_pages = end - start;
 255
 256         /* Allocate bio integrity payload and integrity vectors */
 257         bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
 258         if (IS_ERR(bip)) {
 259                 printk(KERN_ERR "could not allocate data integrity bioset\n");
 260                 kfree(buf);
 261                 status = BLK_STS_RESOURCE;
 262                 goto err_end_io;
 263         }
 264
 265         bip->bip_flags |= BIP_BLOCK_INTEGRITY;
 266         bip->bip_iter.bi_size = len;
 267         bip_set_seed(bip, bio->bi_iter.bi_sector);
 268
 269         if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
 270                 bip->bip_flags |= BIP_IP_CHECKSUM;
 271
 272         /* Map it */
 273         offset = offset_in_page(buf);
 274         for (i = 0 ; i < nr_pages ; i++) {
 275                 int ret;
 276                 bytes = PAGE_SIZE - offset;
 277
 278                 if (len <= 0)
 279                         break;
 280
 281                 if (bytes > len)
 282                         bytes = len;
 283
 284                 ret = bio_integrity_add_page(bio, virt_to_page(buf),
 285                                              bytes, offset);
 286
 287                 if (ret == 0) {
 288                         printk(KERN_ERR "could not attach integrity payload\n");
 289                         status = BLK_STS_RESOURCE;
 290                         goto err_end_io;
 291                 }
 292
 293                 if (ret < bytes)
 294                         break;
 295
 296                 buf += bytes;
 297                 len -= bytes;
 298                 offset = 0;
 299         }
 300
 301         /* Auto-generate integrity metadata if this is a write */
 302         if (bio_data_dir(bio) == WRITE) {
 303                 bio_integrity_process(bio, &bio->bi_iter,
 304                                       bi->profile->generate_fn);
 305         } else {
 306                 bip->bio_iter = bio->bi_iter;
 307         }
 308         return true;
 309
 310 err_end_io:
 311         bio->bi_status = status;
 312         bio_endio(bio);
 313         return false;
 314
 315 }
 316 EXPORT_SYMBOL(bio_integrity_prep);
 317
 318 /**
 319  * bio_integrity_verify_fn - Integrity I/O completion worker
 320  * @work:       Work struct stored in bio to be verified
 321  *
 322  * Description: This workqueue function is called to complete a READ
 323  * request.  The function verifies the transferred integrity metadata
 324  * and then calls the original bio end_io function.
 325  */
 326 static void bio_integrity_verify_fn(struct work_struct *work)
 327 {
 328         struct bio_integrity_payload *bip =
 329                 container_of(work, struct bio_integrity_payload, bip_work);
 330         struct bio *bio = bip->bip_bio;
 331         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 332
 333         /*
 334          * At the moment verify is called bio's iterator was advanced
 335          * during split and completion, we need to rewind iterator to
 336          * it's original position.
 337          */
 338         bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
 339                                                 bi->profile->verify_fn);
 340         bio_integrity_free(bio);
 341         bio_endio(bio);
 342 }
 343
 344 /**
 345  * __bio_integrity_endio - Integrity I/O completion function
 346  * @bio:        Protected bio
 347  *
 348  * Description: Completion for integrity I/O
 349  *
 350  * Normally I/O completion is done in interrupt context.  However,
 351  * verifying I/O integrity is a time-consuming task which must be run
 352  * in process context.  This function postpones completion
 353  * accordingly.
 354  */
 355 bool __bio_integrity_endio(struct bio *bio)
 356 {
 357         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 358         struct bio_integrity_payload *bip = bio_integrity(bio);
 359
 360         if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
 361             (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
 362                 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 363                 queue_work(kintegrityd_wq, &bip->bip_work);
 364                 return false;
 365         }
 366
 367         bio_integrity_free(bio);
 368         return true;
 369 }
 370
 371 /**
 372  * bio_integrity_advance - Advance integrity vector
 373  * @bio:        bio whose integrity vector to update
 374  * @bytes_done: number of data bytes that have been completed
 375  *
 376  * Description: This function calculates how many integrity bytes the
 377  * number of completed data bytes correspond to and advances the
 378  * integrity vector accordingly.
 379  */
 380 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 381 {
 382         struct bio_integrity_payload *bip = bio_integrity(bio);
 383         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 384         unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 385
 386         bip->bip_iter.bi_sector += bytes_done >> 9;
 387         bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
 388 }
 389
 390 /**
 391  * bio_integrity_trim - Trim integrity vector
 392  * @bio:        bio whose integrity vector to update
 393  *
 394  * Description: Used to trim the integrity vector in a cloned bio.
 395  */
 396 void bio_integrity_trim(struct bio *bio)
 397 {
 398         struct bio_integrity_payload *bip = bio_integrity(bio);
 399         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 400
 401         bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 402 }
 403 EXPORT_SYMBOL(bio_integrity_trim);
 404
 405 /**
 406  * bio_integrity_clone - Callback for cloning bios with integrity metadata
 407  * @bio:        New bio
 408  * @bio_src:    Original bio
 409  * @gfp_mask:   Memory allocation mask
 410  *
 411  * Description: Called to allocate a bip when cloning a bio
 412  */
 413 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 414                         gfp_t gfp_mask)
 415 {
 416         struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
 417         struct bio_integrity_payload *bip;
 418
 419         BUG_ON(bip_src == NULL);
 420
 421         bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
 422         if (IS_ERR(bip))
 423                 return PTR_ERR(bip);
 424
 425         memcpy(bip->bip_vec, bip_src->bip_vec,
 426                bip_src->bip_vcnt * sizeof(struct bio_vec));
 427
 428         bip->bip_vcnt = bip_src->bip_vcnt;
 429         bip->bip_iter = bip_src->bip_iter;
 430
 431         return 0;
 432 }
 433 EXPORT_SYMBOL(bio_integrity_clone);
 434
 435 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 436 {
 437         if (mempool_initialized(&bs->bio_integrity_pool))
 438                 return 0;
 439
 440         if (mempool_init_slab_pool(&bs->bio_integrity_pool,
 441                                    pool_size, bip_slab))
 442                 return -1;
 443
 444         if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
 445                 mempool_exit(&bs->bio_integrity_pool);
 446                 return -1;
 447         }
 448
 449         return 0;
 450 }
 451 EXPORT_SYMBOL(bioset_integrity_create);
 452
 453 void bioset_integrity_free(struct bio_set *bs)
 454 {
 455         mempool_exit(&bs->bio_integrity_pool);
 456         mempool_exit(&bs->bvec_integrity_pool);
 457 }
 458
 459 void __init bio_integrity_init(void)
 460 {
 461         /*
 462          * kintegrityd won't block much but may burn a lot of CPU cycles.
 463          * Make it highpri CPU intensive wq with max concurrency of 1.
 464          */
 465         kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
 466                                          WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
 467         if (!kintegrityd_wq)
 468                 panic("Failed to create kintegrityd\n");
 469
 470         bip_slab = kmem_cache_create("bio_integrity_payload",
 471                                      sizeof(struct bio_integrity_payload) +
 472                                      sizeof(struct bio_vec) * BIP_INLINE_VECS,
 473                                      0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 474 }