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