2 * bio-integrity.c - bio data integrity extensions
4 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
5 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; see the file COPYING. If not, write to
18 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
23 #include <linux/blkdev.h>
24 #include <linux/mempool.h>
25 #include <linux/bio.h>
26 #include <linux/workqueue.h>
28 struct integrity_slab {
29 struct kmem_cache *slab;
30 unsigned short nr_vecs;
34 #define IS(x) { .nr_vecs = x, .name = "bip-"__stringify(x) }
35 struct integrity_slab bip_slab[BIOVEC_NR_POOLS] __read_mostly = {
36 IS(1), IS(4), IS(16), IS(64), IS(128), IS(BIO_MAX_PAGES),
40 static struct workqueue_struct *kintegrityd_wq;
42 static inline unsigned int vecs_to_idx(unsigned int nr)
55 case 129 ... BIO_MAX_PAGES:
62 static inline int use_bip_pool(unsigned int idx)
64 if (idx == BIOVEC_MAX_IDX)
71 * bio_integrity_alloc_bioset - Allocate integrity payload and attach it to bio
72 * @bio: bio to attach integrity metadata to
73 * @gfp_mask: Memory allocation mask
74 * @nr_vecs: Number of integrity metadata scatter-gather elements
75 * @bs: bio_set to allocate from
77 * Description: This function prepares a bio for attaching integrity
78 * metadata. nr_vecs specifies the maximum number of pages containing
79 * integrity metadata that can be attached.
81 struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *bio,
86 struct bio_integrity_payload *bip;
87 unsigned int idx = vecs_to_idx(nr_vecs);
92 /* Lower order allocations come straight from slab */
93 if (!use_bip_pool(idx))
94 bip = kmem_cache_alloc(bip_slab[idx].slab, gfp_mask);
96 /* Use mempool if lower order alloc failed or max vecs were requested */
98 idx = BIOVEC_MAX_IDX; /* so we free the payload properly later */
99 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
101 if (unlikely(bip == NULL)) {
102 printk(KERN_ERR "%s: could not alloc bip\n", __func__);
107 memset(bip, 0, sizeof(*bip));
111 bio->bi_integrity = bip;
115 EXPORT_SYMBOL(bio_integrity_alloc_bioset);
118 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
119 * @bio: bio to attach integrity metadata to
120 * @gfp_mask: Memory allocation mask
121 * @nr_vecs: Number of integrity metadata scatter-gather elements
123 * Description: This function prepares a bio for attaching integrity
124 * metadata. nr_vecs specifies the maximum number of pages containing
125 * integrity metadata that can be attached.
127 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
129 unsigned int nr_vecs)
131 return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set);
133 EXPORT_SYMBOL(bio_integrity_alloc);
136 * bio_integrity_free - Free bio integrity payload
137 * @bio: bio containing bip to be freed
138 * @bs: bio_set this bio was allocated from
140 * Description: Used to free the integrity portion of a bio. Usually
141 * called from bio_free().
143 void bio_integrity_free(struct bio *bio, struct bio_set *bs)
145 struct bio_integrity_payload *bip = bio->bi_integrity;
149 /* A cloned bio doesn't own the integrity metadata */
150 if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
151 && bip->bip_buf != NULL)
154 if (use_bip_pool(bip->bip_slab))
155 mempool_free(bip, bs->bio_integrity_pool);
157 kmem_cache_free(bip_slab[bip->bip_slab].slab, bip);
159 bio->bi_integrity = NULL;
161 EXPORT_SYMBOL(bio_integrity_free);
164 * bio_integrity_add_page - Attach integrity metadata
165 * @bio: bio to update
166 * @page: page containing integrity metadata
167 * @len: number of bytes of integrity metadata in page
168 * @offset: start offset within page
170 * Description: Attach a page containing integrity metadata to bio.
172 int bio_integrity_add_page(struct bio *bio, struct page *page,
173 unsigned int len, unsigned int offset)
175 struct bio_integrity_payload *bip = bio->bi_integrity;
178 if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
179 printk(KERN_ERR "%s: bip_vec full\n", __func__);
183 iv = bip_vec_idx(bip, bip->bip_vcnt);
188 iv->bv_offset = offset;
193 EXPORT_SYMBOL(bio_integrity_add_page);
195 static int bdev_integrity_enabled(struct block_device *bdev, int rw)
197 struct blk_integrity *bi = bdev_get_integrity(bdev);
202 if (rw == READ && bi->verify_fn != NULL &&
203 (bi->flags & INTEGRITY_FLAG_READ))
206 if (rw == WRITE && bi->generate_fn != NULL &&
207 (bi->flags & INTEGRITY_FLAG_WRITE))
214 * bio_integrity_enabled - Check whether integrity can be passed
217 * Description: Determines whether bio_integrity_prep() can be called
218 * on this bio or not. bio data direction and target device must be
219 * set prior to calling. The functions honors the write_generate and
220 * read_verify flags in sysfs.
222 int bio_integrity_enabled(struct bio *bio)
224 /* Already protected? */
225 if (bio_integrity(bio))
228 return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio));
230 EXPORT_SYMBOL(bio_integrity_enabled);
233 * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
234 * @bi: blk_integrity profile for device
235 * @sectors: Number of 512 sectors to convert
237 * Description: The block layer calculates everything in 512 byte
238 * sectors but integrity metadata is done in terms of the hardware
239 * sector size of the storage device. Convert the block layer sectors
240 * to physical sectors.
242 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi,
243 unsigned int sectors)
245 /* At this point there are only 512b or 4096b DIF/EPP devices */
246 if (bi->sector_size == 4096)
247 return sectors >>= 3;
253 * bio_integrity_tag_size - Retrieve integrity tag space
254 * @bio: bio to inspect
256 * Description: Returns the maximum number of tag bytes that can be
257 * attached to this bio. Filesystems can use this to determine how
258 * much metadata to attach to an I/O.
260 unsigned int bio_integrity_tag_size(struct bio *bio)
262 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
264 BUG_ON(bio->bi_size == 0);
266 return bi->tag_size * (bio->bi_size / bi->sector_size);
268 EXPORT_SYMBOL(bio_integrity_tag_size);
270 int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set)
272 struct bio_integrity_payload *bip = bio->bi_integrity;
273 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
274 unsigned int nr_sectors;
276 BUG_ON(bip->bip_buf == NULL);
278 if (bi->tag_size == 0)
281 nr_sectors = bio_integrity_hw_sectors(bi,
282 DIV_ROUND_UP(len, bi->tag_size));
284 if (nr_sectors * bi->tuple_size > bip->bip_size) {
285 printk(KERN_ERR "%s: tag too big for bio: %u > %u\n",
286 __func__, nr_sectors * bi->tuple_size, bip->bip_size);
291 bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
293 bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
299 * bio_integrity_set_tag - Attach a tag buffer to a bio
300 * @bio: bio to attach buffer to
301 * @tag_buf: Pointer to a buffer containing tag data
302 * @len: Length of the included buffer
304 * Description: Use this function to tag a bio by leveraging the extra
305 * space provided by devices formatted with integrity protection. The
306 * size of the integrity buffer must be <= to the size reported by
307 * bio_integrity_tag_size().
309 int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len)
311 BUG_ON(bio_data_dir(bio) != WRITE);
313 return bio_integrity_tag(bio, tag_buf, len, 1);
315 EXPORT_SYMBOL(bio_integrity_set_tag);
318 * bio_integrity_get_tag - Retrieve a tag buffer from a bio
319 * @bio: bio to retrieve buffer from
320 * @tag_buf: Pointer to a buffer for the tag data
321 * @len: Length of the target buffer
323 * Description: Use this function to retrieve the tag buffer from a
324 * completed I/O. The size of the integrity buffer must be <= to the
325 * size reported by bio_integrity_tag_size().
327 int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
329 BUG_ON(bio_data_dir(bio) != READ);
331 return bio_integrity_tag(bio, tag_buf, len, 0);
333 EXPORT_SYMBOL(bio_integrity_get_tag);
336 * bio_integrity_generate - Generate integrity metadata for a bio
337 * @bio: bio to generate integrity metadata for
339 * Description: Generates integrity metadata for a bio by calling the
340 * block device's generation callback function. The bio must have a
341 * bip attached with enough room to accommodate the generated
342 * integrity metadata.
344 static void bio_integrity_generate(struct bio *bio)
346 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
347 struct blk_integrity_exchg bix;
349 sector_t sector = bio->bi_sector;
350 unsigned int i, sectors, total;
351 void *prot_buf = bio->bi_integrity->bip_buf;
354 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
355 bix.sector_size = bi->sector_size;
357 bio_for_each_segment(bv, bio, i) {
358 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
359 bix.data_buf = kaddr + bv->bv_offset;
360 bix.data_size = bv->bv_len;
361 bix.prot_buf = prot_buf;
364 bi->generate_fn(&bix);
366 sectors = bv->bv_len / bi->sector_size;
368 prot_buf += sectors * bi->tuple_size;
369 total += sectors * bi->tuple_size;
370 BUG_ON(total > bio->bi_integrity->bip_size);
372 kunmap_atomic(kaddr, KM_USER0);
376 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
379 return bi->tuple_size;
385 * bio_integrity_prep - Prepare bio for integrity I/O
386 * @bio: bio to prepare
388 * Description: Allocates a buffer for integrity metadata, maps the
389 * pages and attaches them to a bio. The bio must have data
390 * direction, target device and start sector set priot to calling. In
391 * the WRITE case, integrity metadata will be generated using the
392 * block device's integrity function. In the READ case, the buffer
393 * will be prepared for DMA and a suitable end_io handler set up.
395 int bio_integrity_prep(struct bio *bio)
397 struct bio_integrity_payload *bip;
398 struct blk_integrity *bi;
399 struct request_queue *q;
401 unsigned long start, end;
402 unsigned int len, nr_pages;
403 unsigned int bytes, offset, i;
404 unsigned int sectors;
406 bi = bdev_get_integrity(bio->bi_bdev);
407 q = bdev_get_queue(bio->bi_bdev);
409 BUG_ON(bio_integrity(bio));
411 sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
413 /* Allocate kernel buffer for protection data */
414 len = sectors * blk_integrity_tuple_size(bi);
415 buf = kmalloc(len, GFP_NOIO | __GFP_NOFAIL | q->bounce_gfp);
416 if (unlikely(buf == NULL)) {
417 printk(KERN_ERR "could not allocate integrity buffer\n");
421 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
422 start = ((unsigned long) buf) >> PAGE_SHIFT;
423 nr_pages = end - start;
425 /* Allocate bio integrity payload and integrity vectors */
426 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
427 if (unlikely(bip == NULL)) {
428 printk(KERN_ERR "could not allocate data integrity bioset\n");
435 bip->bip_sector = bio->bi_sector;
438 offset = offset_in_page(buf);
439 for (i = 0 ; i < nr_pages ; i++) {
441 bytes = PAGE_SIZE - offset;
449 ret = bio_integrity_add_page(bio, virt_to_page(buf),
463 /* Install custom I/O completion handler if read verify is enabled */
464 if (bio_data_dir(bio) == READ) {
465 bip->bip_end_io = bio->bi_end_io;
466 bio->bi_end_io = bio_integrity_endio;
469 /* Auto-generate integrity metadata if this is a write */
470 if (bio_data_dir(bio) == WRITE)
471 bio_integrity_generate(bio);
475 EXPORT_SYMBOL(bio_integrity_prep);
478 * bio_integrity_verify - Verify integrity metadata for a bio
479 * @bio: bio to verify
481 * Description: This function is called to verify the integrity of a
482 * bio. The data in the bio io_vec is compared to the integrity
483 * metadata returned by the HBA.
485 static int bio_integrity_verify(struct bio *bio)
487 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
488 struct blk_integrity_exchg bix;
490 sector_t sector = bio->bi_integrity->bip_sector;
491 unsigned int i, sectors, total, ret;
492 void *prot_buf = bio->bi_integrity->bip_buf;
495 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
496 bix.sector_size = bi->sector_size;
498 bio_for_each_segment(bv, bio, i) {
499 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
500 bix.data_buf = kaddr + bv->bv_offset;
501 bix.data_size = bv->bv_len;
502 bix.prot_buf = prot_buf;
505 ret = bi->verify_fn(&bix);
508 kunmap_atomic(kaddr, KM_USER0);
512 sectors = bv->bv_len / bi->sector_size;
514 prot_buf += sectors * bi->tuple_size;
515 total += sectors * bi->tuple_size;
516 BUG_ON(total > bio->bi_integrity->bip_size);
518 kunmap_atomic(kaddr, KM_USER0);
525 * bio_integrity_verify_fn - Integrity I/O completion worker
526 * @work: Work struct stored in bio to be verified
528 * Description: This workqueue function is called to complete a READ
529 * request. The function verifies the transferred integrity metadata
530 * and then calls the original bio end_io function.
532 static void bio_integrity_verify_fn(struct work_struct *work)
534 struct bio_integrity_payload *bip =
535 container_of(work, struct bio_integrity_payload, bip_work);
536 struct bio *bio = bip->bip_bio;
539 error = bio_integrity_verify(bio);
541 /* Restore original bio completion handler */
542 bio->bi_end_io = bip->bip_end_io;
543 bio_endio(bio, error);
547 * bio_integrity_endio - Integrity I/O completion function
548 * @bio: Protected bio
549 * @error: Pointer to errno
551 * Description: Completion for integrity I/O
553 * Normally I/O completion is done in interrupt context. However,
554 * verifying I/O integrity is a time-consuming task which must be run
555 * in process context. This function postpones completion
558 void bio_integrity_endio(struct bio *bio, int error)
560 struct bio_integrity_payload *bip = bio->bi_integrity;
562 BUG_ON(bip->bip_bio != bio);
564 /* In case of an I/O error there is no point in verifying the
565 * integrity metadata. Restore original bio end_io handler
569 bio->bi_end_io = bip->bip_end_io;
570 bio_endio(bio, error);
575 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
576 queue_work(kintegrityd_wq, &bip->bip_work);
578 EXPORT_SYMBOL(bio_integrity_endio);
581 * bio_integrity_mark_head - Advance bip_vec skip bytes
582 * @bip: Integrity vector to advance
583 * @skip: Number of bytes to advance it
585 void bio_integrity_mark_head(struct bio_integrity_payload *bip,
591 bip_for_each_vec(iv, bip, i) {
595 } else if (skip >= iv->bv_len) {
597 } else { /* skip < iv->bv_len) */
598 iv->bv_offset += skip;
607 * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long
608 * @bip: Integrity vector to truncate
609 * @len: New length of integrity vector
611 void bio_integrity_mark_tail(struct bio_integrity_payload *bip,
617 bip_for_each_vec(iv, bip, i) {
621 } else if (len >= iv->bv_len) {
623 } else { /* len < iv->bv_len) */
631 * bio_integrity_advance - Advance integrity vector
632 * @bio: bio whose integrity vector to update
633 * @bytes_done: number of data bytes that have been completed
635 * Description: This function calculates how many integrity bytes the
636 * number of completed data bytes correspond to and advances the
637 * integrity vector accordingly.
639 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
641 struct bio_integrity_payload *bip = bio->bi_integrity;
642 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
643 unsigned int nr_sectors;
648 nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9);
649 bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size);
651 EXPORT_SYMBOL(bio_integrity_advance);
654 * bio_integrity_trim - Trim integrity vector
655 * @bio: bio whose integrity vector to update
656 * @offset: offset to first data sector
657 * @sectors: number of data sectors
659 * Description: Used to trim the integrity vector in a cloned bio.
660 * The ivec will be advanced corresponding to 'offset' data sectors
661 * and the length will be truncated corresponding to 'len' data
664 void bio_integrity_trim(struct bio *bio, unsigned int offset,
665 unsigned int sectors)
667 struct bio_integrity_payload *bip = bio->bi_integrity;
668 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
669 unsigned int nr_sectors;
673 BUG_ON(!bio_flagged(bio, BIO_CLONED));
675 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
676 bip->bip_sector = bip->bip_sector + offset;
677 bio_integrity_mark_head(bip, offset * bi->tuple_size);
678 bio_integrity_mark_tail(bip, sectors * bi->tuple_size);
680 EXPORT_SYMBOL(bio_integrity_trim);
683 * bio_integrity_split - Split integrity metadata
684 * @bio: Protected bio
685 * @bp: Resulting bio_pair
688 * Description: Splits an integrity page into a bio_pair.
690 void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
692 struct blk_integrity *bi;
693 struct bio_integrity_payload *bip = bio->bi_integrity;
694 unsigned int nr_sectors;
696 if (bio_integrity(bio) == 0)
699 bi = bdev_get_integrity(bio->bi_bdev);
701 BUG_ON(bip->bip_vcnt != 1);
703 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
705 bp->bio1.bi_integrity = &bp->bip1;
706 bp->bio2.bi_integrity = &bp->bip2;
708 bp->iv1 = bip->bip_vec[0];
709 bp->iv2 = bip->bip_vec[0];
711 bp->bip1.bip_vec[0] = bp->iv1;
712 bp->bip2.bip_vec[0] = bp->iv2;
714 bp->iv1.bv_len = sectors * bi->tuple_size;
715 bp->iv2.bv_offset += sectors * bi->tuple_size;
716 bp->iv2.bv_len -= sectors * bi->tuple_size;
718 bp->bip1.bip_sector = bio->bi_integrity->bip_sector;
719 bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors;
721 bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1;
722 bp->bip1.bip_idx = bp->bip2.bip_idx = 0;
724 EXPORT_SYMBOL(bio_integrity_split);
727 * bio_integrity_clone - Callback for cloning bios with integrity metadata
729 * @bio_src: Original bio
730 * @gfp_mask: Memory allocation mask
731 * @bs: bio_set to allocate bip from
733 * Description: Called to allocate a bip when cloning a bio
735 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
736 gfp_t gfp_mask, struct bio_set *bs)
738 struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
739 struct bio_integrity_payload *bip;
741 BUG_ON(bip_src == NULL);
743 bip = bio_integrity_alloc_bioset(bio, gfp_mask, bip_src->bip_vcnt, bs);
748 memcpy(bip->bip_vec, bip_src->bip_vec,
749 bip_src->bip_vcnt * sizeof(struct bio_vec));
751 bip->bip_sector = bip_src->bip_sector;
752 bip->bip_vcnt = bip_src->bip_vcnt;
753 bip->bip_idx = bip_src->bip_idx;
757 EXPORT_SYMBOL(bio_integrity_clone);
759 int bioset_integrity_create(struct bio_set *bs, int pool_size)
761 unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
763 bs->bio_integrity_pool =
764 mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
766 if (!bs->bio_integrity_pool)
771 EXPORT_SYMBOL(bioset_integrity_create);
773 void bioset_integrity_free(struct bio_set *bs)
775 if (bs->bio_integrity_pool)
776 mempool_destroy(bs->bio_integrity_pool);
778 EXPORT_SYMBOL(bioset_integrity_free);
780 void __init bio_integrity_init(void)
784 kintegrityd_wq = create_workqueue("kintegrityd");
786 panic("Failed to create kintegrityd\n");
788 for (i = 0 ; i < BIOVEC_NR_POOLS ; i++) {
791 size = sizeof(struct bio_integrity_payload)
792 + bip_slab[i].nr_vecs * sizeof(struct bio_vec);
795 kmem_cache_create(bip_slab[i].name, size, 0,
796 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);