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