2 * bio-integrity.c - bio data integrity extensions
4 * Copyright (C) 2007, 2008 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 static struct kmem_cache *bio_integrity_slab __read_mostly;
29 static struct workqueue_struct *kintegrityd_wq;
32 * bio_integrity_alloc_bioset - Allocate integrity payload and attach it to bio
33 * @bio: bio to attach integrity metadata to
34 * @gfp_mask: Memory allocation mask
35 * @nr_vecs: Number of integrity metadata scatter-gather elements
36 * @bs: bio_set to allocate from
38 * Description: This function prepares a bio for attaching integrity
39 * metadata. nr_vecs specifies the maximum number of pages containing
40 * integrity metadata that can be attached.
42 struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs, struct bio_set *bs)
44 struct bio_integrity_payload *bip;
50 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
51 if (unlikely(bip == NULL)) {
52 printk(KERN_ERR "%s: could not alloc bip\n", __func__);
56 memset(bip, 0, sizeof(*bip));
58 iv = bvec_alloc_bs(gfp_mask, nr_vecs, &idx, bs);
59 if (unlikely(iv == NULL)) {
60 printk(KERN_ERR "%s: could not alloc bip_vec\n", __func__);
61 mempool_free(bip, bs->bio_integrity_pool);
68 bio->bi_integrity = bip;
72 EXPORT_SYMBOL(bio_integrity_alloc_bioset);
75 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
76 * @bio: bio to attach integrity metadata to
77 * @gfp_mask: Memory allocation mask
78 * @nr_vecs: Number of integrity metadata scatter-gather elements
80 * Description: This function prepares a bio for attaching integrity
81 * metadata. nr_vecs specifies the maximum number of pages containing
82 * integrity metadata that can be attached.
84 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs)
86 return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set);
88 EXPORT_SYMBOL(bio_integrity_alloc);
91 * bio_integrity_free - Free bio integrity payload
92 * @bio: bio containing bip to be freed
93 * @bs: bio_set this bio was allocated from
95 * Description: Used to free the integrity portion of a bio. Usually
96 * called from bio_free().
98 void bio_integrity_free(struct bio *bio, struct bio_set *bs)
100 struct bio_integrity_payload *bip = bio->bi_integrity;
104 /* A cloned bio doesn't own the integrity metadata */
105 if (!bio_flagged(bio, BIO_CLONED) && bip->bip_buf != NULL)
108 mempool_free(bip->bip_vec, bs->bvec_pools[bip->bip_pool]);
109 mempool_free(bip, bs->bio_integrity_pool);
111 bio->bi_integrity = NULL;
113 EXPORT_SYMBOL(bio_integrity_free);
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
122 * Description: Attach a page containing integrity metadata to bio.
124 int bio_integrity_add_page(struct bio *bio, struct page *page,
125 unsigned int len, unsigned int offset)
127 struct bio_integrity_payload *bip = bio->bi_integrity;
130 if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_pool)) {
131 printk(KERN_ERR "%s: bip_vec full\n", __func__);
135 iv = bip_vec_idx(bip, bip->bip_vcnt);
137 BUG_ON(iv->bv_page != NULL);
141 iv->bv_offset = offset;
146 EXPORT_SYMBOL(bio_integrity_add_page);
149 * bio_integrity_enabled - Check whether integrity can be passed
152 * Description: Determines whether bio_integrity_prep() can be called
153 * on this bio or not. bio data direction and target device must be
154 * set prior to calling. The functions honors the write_generate and
155 * read_verify flags in sysfs.
157 int bio_integrity_enabled(struct bio *bio)
159 /* Already protected? */
160 if (bio_integrity(bio))
163 return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio));
165 EXPORT_SYMBOL(bio_integrity_enabled);
168 * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
169 * @bi: blk_integrity profile for device
170 * @sectors: Number of 512 sectors to convert
172 * Description: The block layer calculates everything in 512 byte
173 * sectors but integrity metadata is done in terms of the hardware
174 * sector size of the storage device. Convert the block layer sectors
175 * to physical sectors.
177 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi, unsigned int sectors)
179 /* At this point there are only 512b or 4096b DIF/EPP devices */
180 if (bi->sector_size == 4096)
181 return sectors >>= 3;
187 * bio_integrity_tag_size - Retrieve integrity tag space
188 * @bio: bio to inspect
190 * Description: Returns the maximum number of tag bytes that can be
191 * attached to this bio. Filesystems can use this to determine how
192 * much metadata to attach to an I/O.
194 unsigned int bio_integrity_tag_size(struct bio *bio)
196 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
198 BUG_ON(bio->bi_size == 0);
200 return bi->tag_size * (bio->bi_size / bi->sector_size);
202 EXPORT_SYMBOL(bio_integrity_tag_size);
204 int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set)
206 struct bio_integrity_payload *bip = bio->bi_integrity;
207 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
208 unsigned int nr_sectors;
210 BUG_ON(bip->bip_buf == NULL);
212 if (bi->tag_size == 0)
215 nr_sectors = bio_integrity_hw_sectors(bi, DIV_ROUND_UP(len, bi->tag_size));
217 if (nr_sectors * bi->tuple_size > bip->bip_size) {
218 printk(KERN_ERR "%s: tag too big for bio: %u > %u\n",
219 __func__, nr_sectors * bi->tuple_size, bip->bip_size);
224 bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
226 bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
232 * bio_integrity_set_tag - Attach a tag buffer to a bio
233 * @bio: bio to attach buffer to
234 * @tag_buf: Pointer to a buffer containing tag data
235 * @len: Length of the included buffer
237 * Description: Use this function to tag a bio by leveraging the extra
238 * space provided by devices formatted with integrity protection. The
239 * size of the integrity buffer must be <= to the size reported by
240 * bio_integrity_tag_size().
242 int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len)
244 BUG_ON(bio_data_dir(bio) != WRITE);
246 return bio_integrity_tag(bio, tag_buf, len, 1);
248 EXPORT_SYMBOL(bio_integrity_set_tag);
251 * bio_integrity_get_tag - Retrieve a tag buffer from a bio
252 * @bio: bio to retrieve buffer from
253 * @tag_buf: Pointer to a buffer for the tag data
254 * @len: Length of the target buffer
256 * Description: Use this function to retrieve the tag buffer from a
257 * completed I/O. The size of the integrity buffer must be <= to the
258 * size reported by bio_integrity_tag_size().
260 int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
262 BUG_ON(bio_data_dir(bio) != READ);
264 return bio_integrity_tag(bio, tag_buf, len, 0);
266 EXPORT_SYMBOL(bio_integrity_get_tag);
269 * bio_integrity_generate - Generate integrity metadata for a bio
270 * @bio: bio to generate integrity metadata for
272 * Description: Generates integrity metadata for a bio by calling the
273 * block device's generation callback function. The bio must have a
274 * bip attached with enough room to accommodate the generated
275 * integrity metadata.
277 static void bio_integrity_generate(struct bio *bio)
279 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
280 struct blk_integrity_exchg bix;
282 sector_t sector = bio->bi_sector;
283 unsigned int i, sectors, total;
284 void *prot_buf = bio->bi_integrity->bip_buf;
287 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
288 bix.sector_size = bi->sector_size;
290 bio_for_each_segment(bv, bio, i) {
291 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
292 bix.data_buf = kaddr + bv->bv_offset;
293 bix.data_size = bv->bv_len;
294 bix.prot_buf = prot_buf;
297 bi->generate_fn(&bix);
299 sectors = bv->bv_len / bi->sector_size;
301 prot_buf += sectors * bi->tuple_size;
302 total += sectors * bi->tuple_size;
303 BUG_ON(total > bio->bi_integrity->bip_size);
305 kunmap_atomic(kaddr, KM_USER0);
310 * bio_integrity_prep - Prepare bio for integrity I/O
311 * @bio: bio to prepare
313 * Description: Allocates a buffer for integrity metadata, maps the
314 * pages and attaches them to a bio. The bio must have data
315 * direction, target device and start sector set priot to calling. In
316 * the WRITE case, integrity metadata will be generated using the
317 * block device's integrity function. In the READ case, the buffer
318 * will be prepared for DMA and a suitable end_io handler set up.
320 int bio_integrity_prep(struct bio *bio)
322 struct bio_integrity_payload *bip;
323 struct blk_integrity *bi;
324 struct request_queue *q;
326 unsigned long start, end;
327 unsigned int len, nr_pages;
328 unsigned int bytes, offset, i;
329 unsigned int sectors;
331 bi = bdev_get_integrity(bio->bi_bdev);
332 q = bdev_get_queue(bio->bi_bdev);
334 BUG_ON(bio_integrity(bio));
336 sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
338 /* Allocate kernel buffer for protection data */
339 len = sectors * blk_integrity_tuple_size(bi);
340 buf = kmalloc(len, GFP_NOIO | __GFP_NOFAIL | q->bounce_gfp);
341 if (unlikely(buf == NULL)) {
342 printk(KERN_ERR "could not allocate integrity buffer\n");
346 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
347 start = ((unsigned long) buf) >> PAGE_SHIFT;
348 nr_pages = end - start;
350 /* Allocate bio integrity payload and integrity vectors */
351 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
352 if (unlikely(bip == NULL)) {
353 printk(KERN_ERR "could not allocate data integrity bioset\n");
360 bip->bip_sector = bio->bi_sector;
363 offset = offset_in_page(buf);
364 for (i = 0 ; i < nr_pages ; i++) {
366 bytes = PAGE_SIZE - offset;
374 ret = bio_integrity_add_page(bio, virt_to_page(buf),
388 /* Install custom I/O completion handler if read verify is enabled */
389 if (bio_data_dir(bio) == READ) {
390 bip->bip_end_io = bio->bi_end_io;
391 bio->bi_end_io = bio_integrity_endio;
394 /* Auto-generate integrity metadata if this is a write */
395 if (bio_data_dir(bio) == WRITE)
396 bio_integrity_generate(bio);
400 EXPORT_SYMBOL(bio_integrity_prep);
403 * bio_integrity_verify - Verify integrity metadata for a bio
404 * @bio: bio to verify
406 * Description: This function is called to verify the integrity of a
407 * bio. The data in the bio io_vec is compared to the integrity
408 * metadata returned by the HBA.
410 static int bio_integrity_verify(struct bio *bio)
412 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
413 struct blk_integrity_exchg bix;
415 sector_t sector = bio->bi_integrity->bip_sector;
416 unsigned int i, sectors, total, ret;
417 void *prot_buf = bio->bi_integrity->bip_buf;
420 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
421 bix.sector_size = bi->sector_size;
423 bio_for_each_segment(bv, bio, i) {
424 void *kaddr = kmap_atomic(bv->bv_page, KM_USER0);
425 bix.data_buf = kaddr + bv->bv_offset;
426 bix.data_size = bv->bv_len;
427 bix.prot_buf = prot_buf;
430 ret = bi->verify_fn(&bix);
433 kunmap_atomic(kaddr, KM_USER0);
437 sectors = bv->bv_len / bi->sector_size;
439 prot_buf += sectors * bi->tuple_size;
440 total += sectors * bi->tuple_size;
441 BUG_ON(total > bio->bi_integrity->bip_size);
443 kunmap_atomic(kaddr, KM_USER0);
450 * bio_integrity_verify_fn - Integrity I/O completion worker
451 * @work: Work struct stored in bio to be verified
453 * Description: This workqueue function is called to complete a READ
454 * request. The function verifies the transferred integrity metadata
455 * and then calls the original bio end_io function.
457 static void bio_integrity_verify_fn(struct work_struct *work)
459 struct bio_integrity_payload *bip =
460 container_of(work, struct bio_integrity_payload, bip_work);
461 struct bio *bio = bip->bip_bio;
462 int error = bip->bip_error;
464 if (bio_integrity_verify(bio)) {
465 clear_bit(BIO_UPTODATE, &bio->bi_flags);
469 /* Restore original bio completion handler */
470 bio->bi_end_io = bip->bip_end_io;
473 bio->bi_end_io(bio, error);
477 * bio_integrity_endio - Integrity I/O completion function
478 * @bio: Protected bio
479 * @error: Pointer to errno
481 * Description: Completion for integrity I/O
483 * Normally I/O completion is done in interrupt context. However,
484 * verifying I/O integrity is a time-consuming task which must be run
485 * in process context. This function postpones completion
488 void bio_integrity_endio(struct bio *bio, int error)
490 struct bio_integrity_payload *bip = bio->bi_integrity;
492 BUG_ON(bip->bip_bio != bio);
494 bip->bip_error = error;
495 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
496 queue_work(kintegrityd_wq, &bip->bip_work);
498 EXPORT_SYMBOL(bio_integrity_endio);
501 * bio_integrity_mark_head - Advance bip_vec skip bytes
502 * @bip: Integrity vector to advance
503 * @skip: Number of bytes to advance it
505 void bio_integrity_mark_head(struct bio_integrity_payload *bip, unsigned int skip)
510 bip_for_each_vec(iv, bip, i) {
514 } else if (skip >= iv->bv_len) {
516 } else { /* skip < iv->bv_len) */
517 iv->bv_offset += skip;
526 * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long
527 * @bip: Integrity vector to truncate
528 * @len: New length of integrity vector
530 void bio_integrity_mark_tail(struct bio_integrity_payload *bip, unsigned int len)
535 bip_for_each_vec(iv, bip, i) {
539 } else if (len >= iv->bv_len) {
541 } else { /* len < iv->bv_len) */
549 * bio_integrity_advance - Advance integrity vector
550 * @bio: bio whose integrity vector to update
551 * @bytes_done: number of data bytes that have been completed
553 * Description: This function calculates how many integrity bytes the
554 * number of completed data bytes correspond to and advances the
555 * integrity vector accordingly.
557 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
559 struct bio_integrity_payload *bip = bio->bi_integrity;
560 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
561 unsigned int nr_sectors;
566 nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9);
567 bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size);
569 EXPORT_SYMBOL(bio_integrity_advance);
572 * bio_integrity_trim - Trim integrity vector
573 * @bio: bio whose integrity vector to update
574 * @offset: offset to first data sector
575 * @sectors: number of data sectors
577 * Description: Used to trim the integrity vector in a cloned bio.
578 * The ivec will be advanced corresponding to 'offset' data sectors
579 * and the length will be truncated corresponding to 'len' data
582 void bio_integrity_trim(struct bio *bio, unsigned int offset, unsigned int sectors)
584 struct bio_integrity_payload *bip = bio->bi_integrity;
585 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
586 unsigned int nr_sectors;
590 BUG_ON(!bio_flagged(bio, BIO_CLONED));
592 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
593 bip->bip_sector = bip->bip_sector + offset;
594 bio_integrity_mark_head(bip, offset * bi->tuple_size);
595 bio_integrity_mark_tail(bip, sectors * bi->tuple_size);
597 EXPORT_SYMBOL(bio_integrity_trim);
600 * bio_integrity_split - Split integrity metadata
601 * @bio: Protected bio
602 * @bp: Resulting bio_pair
605 * Description: Splits an integrity page into a bio_pair.
607 void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
609 struct blk_integrity *bi;
610 struct bio_integrity_payload *bip = bio->bi_integrity;
611 unsigned int nr_sectors;
613 if (bio_integrity(bio) == 0)
616 bi = bdev_get_integrity(bio->bi_bdev);
618 BUG_ON(bip->bip_vcnt != 1);
620 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
622 bp->bio1.bi_integrity = &bp->bip1;
623 bp->bio2.bi_integrity = &bp->bip2;
625 bp->iv1 = bip->bip_vec[0];
626 bp->iv2 = bip->bip_vec[0];
628 bp->bip1.bip_vec = &bp->iv1;
629 bp->bip2.bip_vec = &bp->iv2;
631 bp->iv1.bv_len = sectors * bi->tuple_size;
632 bp->iv2.bv_offset += sectors * bi->tuple_size;
633 bp->iv2.bv_len -= sectors * bi->tuple_size;
635 bp->bip1.bip_sector = bio->bi_integrity->bip_sector;
636 bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors;
638 bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1;
639 bp->bip1.bip_idx = bp->bip2.bip_idx = 0;
641 EXPORT_SYMBOL(bio_integrity_split);
644 * bio_integrity_clone - Callback for cloning bios with integrity metadata
646 * @bio_src: Original bio
647 * @bs: bio_set to allocate bip from
649 * Description: Called to allocate a bip when cloning a bio
651 int bio_integrity_clone(struct bio *bio, struct bio *bio_src, struct bio_set *bs)
653 struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
654 struct bio_integrity_payload *bip;
656 BUG_ON(bip_src == NULL);
658 bip = bio_integrity_alloc_bioset(bio, GFP_NOIO, bip_src->bip_vcnt, bs);
663 memcpy(bip->bip_vec, bip_src->bip_vec,
664 bip_src->bip_vcnt * sizeof(struct bio_vec));
666 bip->bip_sector = bip_src->bip_sector;
667 bip->bip_vcnt = bip_src->bip_vcnt;
668 bip->bip_idx = bip_src->bip_idx;
672 EXPORT_SYMBOL(bio_integrity_clone);
674 int bioset_integrity_create(struct bio_set *bs, int pool_size)
676 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size,
678 if (!bs->bio_integrity_pool)
683 EXPORT_SYMBOL(bioset_integrity_create);
685 void bioset_integrity_free(struct bio_set *bs)
687 if (bs->bio_integrity_pool)
688 mempool_destroy(bs->bio_integrity_pool);
690 EXPORT_SYMBOL(bioset_integrity_free);
692 void __init bio_integrity_init_slab(void)
694 bio_integrity_slab = KMEM_CACHE(bio_integrity_payload,
695 SLAB_HWCACHE_ALIGN|SLAB_PANIC);
697 EXPORT_SYMBOL(bio_integrity_init_slab);
699 static int __init integrity_init(void)
701 kintegrityd_wq = create_workqueue("kintegrityd");
704 panic("Failed to create kintegrityd\n");
708 subsys_initcall(integrity_init);