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