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 static void __bio_integrity_free(struct bio_set *bs,
  28                                  struct bio_integrity_payload *bip)
  29 {
  30         if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
  31                 if (bip->bip_vec)
  32                         bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
  33                                   bip->bip_slab);
  34                 mempool_free(bip, &bs->bio_integrity_pool);
  35         } else {
  36                 kfree(bip);
  37         }
  38 }
  39
  40 /**
  41  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
  42  * @bio:        bio to attach integrity metadata to
  43  * @gfp_mask:   Memory allocation mask
  44  * @nr_vecs:    Number of integrity metadata scatter-gather elements
  45  *
  46  * Description: This function prepares a bio for attaching integrity
  47  * metadata.  nr_vecs specifies the maximum number of pages containing
  48  * integrity metadata that can be attached.
  49  */
  50 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
  51                                                   gfp_t gfp_mask,
  52                                                   unsigned int nr_vecs)
  53 {
  54         struct bio_integrity_payload *bip;
  55         struct bio_set *bs = bio->bi_pool;
  56         unsigned inline_vecs;
  57
  58         if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
  59                 return ERR_PTR(-EOPNOTSUPP);
  60
  61         if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
  62                 bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
  63                 inline_vecs = nr_vecs;
  64         } else {
  65                 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
  66                 inline_vecs = BIP_INLINE_VECS;
  67         }
  68
  69         if (unlikely(!bip))
  70                 return ERR_PTR(-ENOMEM);
  71
  72         memset(bip, 0, sizeof(*bip));
  73
  74         if (nr_vecs > inline_vecs) {
  75                 unsigned long idx = 0;
  76
  77                 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
  78                                           &bs->bvec_integrity_pool);
  79                 if (!bip->bip_vec)
  80                         goto err;
  81                 bip->bip_max_vcnt = bvec_nr_vecs(idx);
  82                 bip->bip_slab = idx;
  83         } else {
  84                 bip->bip_vec = bip->bip_inline_vecs;
  85                 bip->bip_max_vcnt = inline_vecs;
  86         }
  87
  88         bip->bip_bio = bio;
  89         bio->bi_integrity = bip;
  90         bio->bi_opf |= REQ_INTEGRITY;
  91
  92         return bip;
  93 err:
  94         __bio_integrity_free(bs, bip);
  95         return ERR_PTR(-ENOMEM);
  96 }
  97 EXPORT_SYMBOL(bio_integrity_alloc);
  98
  99 /**
 100  * bio_integrity_free - Free bio integrity payload
 101  * @bio:        bio containing bip to be freed
 102  *
 103  * Description: Used to free the integrity portion of a bio. Usually
 104  * called from bio_free().
 105  */
 106 void bio_integrity_free(struct bio *bio)
 107 {
 108         struct bio_integrity_payload *bip = bio_integrity(bio);
 109         struct bio_set *bs = bio->bi_pool;
 110
 111         if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
 112                 kfree(page_address(bip->bip_vec->bv_page) +
 113                       bip->bip_vec->bv_offset);
 114
 115         __bio_integrity_free(bs, bip);
 116         bio->bi_integrity = NULL;
 117         bio->bi_opf &= ~REQ_INTEGRITY;
 118 }
 119
 120 /**
 121  * bio_integrity_add_page - Attach integrity metadata
 122  * @bio:        bio to update
 123  * @page:       page containing integrity metadata
 124  * @len:        number of bytes of integrity metadata in page
 125  * @offset:     start offset within page
 126  *
 127  * Description: Attach a page containing integrity metadata to bio.
 128  */
 129 int bio_integrity_add_page(struct bio *bio, struct page *page,
 130                            unsigned int len, unsigned int offset)
 131 {
 132         struct bio_integrity_payload *bip = bio_integrity(bio);
 133         struct bio_vec *iv;
 134
 135         if (bip->bip_vcnt >= bip->bip_max_vcnt) {
 136                 printk(KERN_ERR "%s: bip_vec full\n", __func__);
 137                 return 0;
 138         }
 139
 140         iv = bip->bip_vec + bip->bip_vcnt;
 141
 142         if (bip->bip_vcnt &&
 143             bvec_gap_to_prev(bio->bi_disk->queue,
 144                              &bip->bip_vec[bip->bip_vcnt - 1], offset))
 145                 return 0;
 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 /**
 157  * bio_integrity_process - Process integrity metadata for a bio
 158  * @bio:        bio to generate/verify integrity metadata for
 159  * @proc_iter:  iterator to process
 160  * @proc_fn:    Pointer to the relevant processing function
 161  */
 162 static blk_status_t bio_integrity_process(struct bio *bio,
 163                 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
 164 {
 165         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 166         struct blk_integrity_iter iter;
 167         struct bvec_iter bviter;
 168         struct bio_vec bv;
 169         struct bio_integrity_payload *bip = bio_integrity(bio);
 170         blk_status_t ret = BLK_STS_OK;
 171         void *prot_buf = page_address(bip->bip_vec->bv_page) +
 172                 bip->bip_vec->bv_offset;
 173
 174         iter.disk_name = bio->bi_disk->disk_name;
 175         iter.interval = 1 << bi->interval_exp;
 176         iter.seed = proc_iter->bi_sector;
 177         iter.prot_buf = prot_buf;
 178
 179         __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
 180                 void *kaddr = kmap_atomic(bv.bv_page);
 181
 182                 iter.data_buf = kaddr + bv.bv_offset;
 183                 iter.data_size = bv.bv_len;
 184
 185                 ret = proc_fn(&iter);
 186                 if (ret) {
 187                         kunmap_atomic(kaddr);
 188                         return ret;
 189                 }
 190
 191                 kunmap_atomic(kaddr);
 192         }
 193         return ret;
 194 }
 195
 196 /**
 197  * bio_integrity_prep - Prepare bio for integrity I/O
 198  * @bio:        bio to prepare
 199  *
 200  * Description:  Checks if the bio already has an integrity payload attached.
 201  * If it does, the payload has been generated by another kernel subsystem,
 202  * and we just pass it through. Otherwise allocates integrity payload.
 203  * The bio must have data direction, target device and start sector set priot
 204  * to calling.  In the WRITE case, integrity metadata will be generated using
 205  * the block device's integrity function.  In the READ case, the buffer
 206  * will be prepared for DMA and a suitable end_io handler set up.
 207  */
 208 bool bio_integrity_prep(struct bio *bio)
 209 {
 210         struct bio_integrity_payload *bip;
 211         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 212         struct request_queue *q = bio->bi_disk->queue;
 213         void *buf;
 214         unsigned long start, end;
 215         unsigned int len, nr_pages;
 216         unsigned int bytes, offset, i;
 217         unsigned int intervals;
 218         blk_status_t status;
 219
 220         if (!bi)
 221                 return true;
 222
 223         if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
 224                 return true;
 225
 226         if (!bio_sectors(bio))
 227                 return true;
 228
 229         /* Already protected? */
 230         if (bio_integrity(bio))
 231                 return true;
 232
 233         if (bio_data_dir(bio) == READ) {
 234                 if (!bi->profile->verify_fn ||
 235                     !(bi->flags & BLK_INTEGRITY_VERIFY))
 236                         return true;
 237         } else {
 238                 if (!bi->profile->generate_fn ||
 239                     !(bi->flags & BLK_INTEGRITY_GENERATE))
 240                         return true;
 241         }
 242         intervals = bio_integrity_intervals(bi, bio_sectors(bio));
 243
 244         /* Allocate kernel buffer for protection data */
 245         len = intervals * bi->tuple_size;
 246         buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
 247         status = BLK_STS_RESOURCE;
 248         if (unlikely(buf == NULL)) {
 249                 printk(KERN_ERR "could not allocate integrity buffer\n");
 250                 goto err_end_io;
 251         }
 252
 253         end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 254         start = ((unsigned long) buf) >> PAGE_SHIFT;
 255         nr_pages = end - start;
 256
 257         /* Allocate bio integrity payload and integrity vectors */
 258         bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
 259         if (IS_ERR(bip)) {
 260                 printk(KERN_ERR "could not allocate data integrity bioset\n");
 261                 kfree(buf);
 262                 status = BLK_STS_RESOURCE;
 263                 goto err_end_io;
 264         }
 265
 266         bip->bip_flags |= BIP_BLOCK_INTEGRITY;
 267         bip->bip_iter.bi_size = len;
 268         bip_set_seed(bip, bio->bi_iter.bi_sector);
 269
 270         if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
 271                 bip->bip_flags |= BIP_IP_CHECKSUM;
 272
 273         /* Map it */
 274         offset = offset_in_page(buf);
 275         for (i = 0 ; i < nr_pages ; i++) {
 276                 int ret;
 277                 bytes = PAGE_SIZE - offset;
 278
 279                 if (len <= 0)
 280                         break;
 281
 282                 if (bytes > len)
 283                         bytes = len;
 284
 285                 ret = bio_integrity_add_page(bio, virt_to_page(buf),
 286                                              bytes, offset);
 287
 288                 if (ret == 0) {
 289                         printk(KERN_ERR "could not attach integrity payload\n");
 290                         status = BLK_STS_RESOURCE;
 291                         goto err_end_io;
 292                 }
 293
 294                 if (ret < bytes)
 295                         break;
 296
 297                 buf += bytes;
 298                 len -= bytes;
 299                 offset = 0;
 300         }
 301
 302         /* Auto-generate integrity metadata if this is a write */
 303         if (bio_data_dir(bio) == WRITE) {
 304                 bio_integrity_process(bio, &bio->bi_iter,
 305                                       bi->profile->generate_fn);
 306         } else {
 307                 bip->bio_iter = bio->bi_iter;
 308         }
 309         return true;
 310
 311 err_end_io:
 312         bio->bi_status = status;
 313         bio_endio(bio);
 314         return false;
 315
 316 }
 317 EXPORT_SYMBOL(bio_integrity_prep);
 318
 319 /**
 320  * bio_integrity_verify_fn - Integrity I/O completion worker
 321  * @work:       Work struct stored in bio to be verified
 322  *
 323  * Description: This workqueue function is called to complete a READ
 324  * request.  The function verifies the transferred integrity metadata
 325  * and then calls the original bio end_io function.
 326  */
 327 static void bio_integrity_verify_fn(struct work_struct *work)
 328 {
 329         struct bio_integrity_payload *bip =
 330                 container_of(work, struct bio_integrity_payload, bip_work);
 331         struct bio *bio = bip->bip_bio;
 332         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 333
 334         /*
 335          * At the moment verify is called bio's iterator was advanced
 336          * during split and completion, we need to rewind iterator to
 337          * it's original position.
 338          */
 339         bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
 340                                                 bi->profile->verify_fn);
 341         bio_integrity_free(bio);
 342         bio_endio(bio);
 343 }
 344
 345 /**
 346  * __bio_integrity_endio - Integrity I/O completion function
 347  * @bio:        Protected bio
 348  *
 349  * Description: Completion for integrity I/O
 350  *
 351  * Normally I/O completion is done in interrupt context.  However,
 352  * verifying I/O integrity is a time-consuming task which must be run
 353  * in process context.  This function postpones completion
 354  * accordingly.
 355  */
 356 bool __bio_integrity_endio(struct bio *bio)
 357 {
 358         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 359         struct bio_integrity_payload *bip = bio_integrity(bio);
 360
 361         if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
 362             (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
 363                 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 364                 queue_work(kintegrityd_wq, &bip->bip_work);
 365                 return false;
 366         }
 367
 368         bio_integrity_free(bio);
 369         return true;
 370 }
 371
 372 /**
 373  * bio_integrity_advance - Advance integrity vector
 374  * @bio:        bio whose integrity vector to update
 375  * @bytes_done: number of data bytes that have been completed
 376  *
 377  * Description: This function calculates how many integrity bytes the
 378  * number of completed data bytes correspond to and advances the
 379  * integrity vector accordingly.
 380  */
 381 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 382 {
 383         struct bio_integrity_payload *bip = bio_integrity(bio);
 384         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 385         unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 386
 387         bip->bip_iter.bi_sector += bytes_done >> 9;
 388         bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
 389 }
 390
 391 /**
 392  * bio_integrity_trim - Trim integrity vector
 393  * @bio:        bio whose integrity vector to update
 394  *
 395  * Description: Used to trim the integrity vector in a cloned bio.
 396  */
 397 void bio_integrity_trim(struct bio *bio)
 398 {
 399         struct bio_integrity_payload *bip = bio_integrity(bio);
 400         struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 401
 402         bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 403 }
 404 EXPORT_SYMBOL(bio_integrity_trim);
 405
 406 /**
 407  * bio_integrity_clone - Callback for cloning bios with integrity metadata
 408  * @bio:        New bio
 409  * @bio_src:    Original bio
 410  * @gfp_mask:   Memory allocation mask
 411  *
 412  * Description: Called to allocate a bip when cloning a bio
 413  */
 414 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 415                         gfp_t gfp_mask)
 416 {
 417         struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
 418         struct bio_integrity_payload *bip;
 419
 420         BUG_ON(bip_src == NULL);
 421
 422         bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
 423         if (IS_ERR(bip))
 424                 return PTR_ERR(bip);
 425
 426         memcpy(bip->bip_vec, bip_src->bip_vec,
 427                bip_src->bip_vcnt * sizeof(struct bio_vec));
 428
 429         bip->bip_vcnt = bip_src->bip_vcnt;
 430         bip->bip_iter = bip_src->bip_iter;
 431
 432         return 0;
 433 }
 434 EXPORT_SYMBOL(bio_integrity_clone);
 435
 436 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 437 {
 438         if (mempool_initialized(&bs->bio_integrity_pool))
 439                 return 0;
 440
 441         if (mempool_init_slab_pool(&bs->bio_integrity_pool,
 442                                    pool_size, bip_slab))
 443                 return -1;
 444
 445         if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
 446                 mempool_exit(&bs->bio_integrity_pool);
 447                 return -1;
 448         }
 449
 450         return 0;
 451 }
 452 EXPORT_SYMBOL(bioset_integrity_create);
 453
 454 void bioset_integrity_free(struct bio_set *bs)
 455 {
 456         mempool_exit(&bs->bio_integrity_pool);
 457         mempool_exit(&bs->bvec_integrity_pool);
 458 }
 459
 460 void __init bio_integrity_init(void)
 461 {
 462         /*
 463          * kintegrityd won't block much but may burn a lot of CPU cycles.
 464          * Make it highpri CPU intensive wq with max concurrency of 1.
 465          */
 466         kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
 467                                          WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
 468         if (!kintegrityd_wq)
 469                 panic("Failed to create kintegrityd\n");
 470
 471         bip_slab = kmem_cache_create("bio_integrity_payload",
 472                                      sizeof(struct bio_integrity_payload) +
 473                                      sizeof(struct bio_vec) * BIP_INLINE_VECS,
 474                                      0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 475 }