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