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/export.h>
26 #include <linux/bio.h>
27 #include <linux/workqueue.h>
28 #include <linux/slab.h>
30 #define BIP_INLINE_VECS 4
32 static struct kmem_cache *bip_slab;
33 static struct workqueue_struct *kintegrityd_wq;
36 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
37 * @bio: bio to attach integrity metadata to
38 * @gfp_mask: Memory allocation mask
39 * @nr_vecs: Number of integrity metadata scatter-gather elements
41 * Description: This function prepares a bio for attaching integrity
42 * metadata. nr_vecs specifies the maximum number of pages containing
43 * integrity metadata that can be attached.
45 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
49 struct bio_integrity_payload *bip;
50 struct bio_set *bs = bio->bi_pool;
51 unsigned long idx = BIO_POOL_NONE;
55 bip = kmalloc(sizeof(struct bio_integrity_payload) +
56 sizeof(struct bio_vec) * nr_vecs, gfp_mask);
57 inline_vecs = nr_vecs;
59 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
60 inline_vecs = BIP_INLINE_VECS;
66 memset(bip, 0, sizeof(*bip));
68 if (nr_vecs > inline_vecs) {
69 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
70 bs->bvec_integrity_pool);
74 bip->bip_vec = bip->bip_inline_vecs;
79 bio->bi_integrity = bip;
83 mempool_free(bip, bs->bio_integrity_pool);
86 EXPORT_SYMBOL(bio_integrity_alloc);
89 * bio_integrity_free - Free bio integrity payload
90 * @bio: bio containing bip to be freed
92 * Description: Used to free the integrity portion of a bio. Usually
93 * called from bio_free().
95 void bio_integrity_free(struct bio *bio)
97 struct bio_integrity_payload *bip = bio->bi_integrity;
98 struct bio_set *bs = bio->bi_pool;
100 if (bip->bip_owns_buf)
104 if (bip->bip_slab != BIO_POOL_NONE)
105 bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
108 mempool_free(bip, bs->bio_integrity_pool);
113 bio->bi_integrity = NULL;
115 EXPORT_SYMBOL(bio_integrity_free);
118 * bio_integrity_add_page - Attach integrity metadata
119 * @bio: bio to update
120 * @page: page containing integrity metadata
121 * @len: number of bytes of integrity metadata in page
122 * @offset: start offset within page
124 * Description: Attach a page containing integrity metadata to bio.
126 int bio_integrity_add_page(struct bio *bio, struct page *page,
127 unsigned int len, unsigned int offset)
129 struct bio_integrity_payload *bip = bio->bi_integrity;
132 if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
133 printk(KERN_ERR "%s: bip_vec full\n", __func__);
137 iv = bip_vec_idx(bip, bip->bip_vcnt);
142 iv->bv_offset = offset;
147 EXPORT_SYMBOL(bio_integrity_add_page);
149 static int bdev_integrity_enabled(struct block_device *bdev, int rw)
151 struct blk_integrity *bi = bdev_get_integrity(bdev);
156 if (rw == READ && bi->verify_fn != NULL &&
157 (bi->flags & INTEGRITY_FLAG_READ))
160 if (rw == WRITE && bi->generate_fn != NULL &&
161 (bi->flags & INTEGRITY_FLAG_WRITE))
168 * bio_integrity_enabled - Check whether integrity can be passed
171 * Description: Determines whether bio_integrity_prep() can be called
172 * on this bio or not. bio data direction and target device must be
173 * set prior to calling. The functions honors the write_generate and
174 * read_verify flags in sysfs.
176 int bio_integrity_enabled(struct bio *bio)
178 /* Already protected? */
179 if (bio_integrity(bio))
182 return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio));
184 EXPORT_SYMBOL(bio_integrity_enabled);
187 * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
188 * @bi: blk_integrity profile for device
189 * @sectors: Number of 512 sectors to convert
191 * Description: The block layer calculates everything in 512 byte
192 * sectors but integrity metadata is done in terms of the hardware
193 * sector size of the storage device. Convert the block layer sectors
194 * to physical sectors.
196 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi,
197 unsigned int sectors)
199 /* At this point there are only 512b or 4096b DIF/EPP devices */
200 if (bi->sector_size == 4096)
201 return sectors >>= 3;
207 * bio_integrity_tag_size - Retrieve integrity tag space
208 * @bio: bio to inspect
210 * Description: Returns the maximum number of tag bytes that can be
211 * attached to this bio. Filesystems can use this to determine how
212 * much metadata to attach to an I/O.
214 unsigned int bio_integrity_tag_size(struct bio *bio)
216 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
218 BUG_ON(bio->bi_iter.bi_size == 0);
220 return bi->tag_size * (bio->bi_iter.bi_size / bi->sector_size);
222 EXPORT_SYMBOL(bio_integrity_tag_size);
224 int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set)
226 struct bio_integrity_payload *bip = bio->bi_integrity;
227 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
228 unsigned int nr_sectors;
230 BUG_ON(bip->bip_buf == NULL);
232 if (bi->tag_size == 0)
235 nr_sectors = bio_integrity_hw_sectors(bi,
236 DIV_ROUND_UP(len, bi->tag_size));
238 if (nr_sectors * bi->tuple_size > bip->bip_size) {
239 printk(KERN_ERR "%s: tag too big for bio: %u > %u\n",
240 __func__, nr_sectors * bi->tuple_size, bip->bip_size);
245 bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
247 bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
253 * bio_integrity_set_tag - Attach a tag buffer to a bio
254 * @bio: bio to attach buffer to
255 * @tag_buf: Pointer to a buffer containing tag data
256 * @len: Length of the included buffer
258 * Description: Use this function to tag a bio by leveraging the extra
259 * space provided by devices formatted with integrity protection. The
260 * size of the integrity buffer must be <= to the size reported by
261 * bio_integrity_tag_size().
263 int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len)
265 BUG_ON(bio_data_dir(bio) != WRITE);
267 return bio_integrity_tag(bio, tag_buf, len, 1);
269 EXPORT_SYMBOL(bio_integrity_set_tag);
272 * bio_integrity_get_tag - Retrieve a tag buffer from a bio
273 * @bio: bio to retrieve buffer from
274 * @tag_buf: Pointer to a buffer for the tag data
275 * @len: Length of the target buffer
277 * Description: Use this function to retrieve the tag buffer from a
278 * completed I/O. The size of the integrity buffer must be <= to the
279 * size reported by bio_integrity_tag_size().
281 int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
283 BUG_ON(bio_data_dir(bio) != READ);
285 return bio_integrity_tag(bio, tag_buf, len, 0);
287 EXPORT_SYMBOL(bio_integrity_get_tag);
290 * bio_integrity_generate - Generate integrity metadata for a bio
291 * @bio: bio to generate integrity metadata for
293 * Description: Generates integrity metadata for a bio by calling the
294 * block device's generation callback function. The bio must have a
295 * bip attached with enough room to accommodate the generated
296 * integrity metadata.
298 static void bio_integrity_generate(struct bio *bio)
300 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
301 struct blk_integrity_exchg bix;
303 struct bvec_iter iter;
304 sector_t sector = bio->bi_iter.bi_sector;
305 unsigned int sectors, total;
306 void *prot_buf = bio->bi_integrity->bip_buf;
309 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
310 bix.sector_size = bi->sector_size;
312 bio_for_each_segment(bv, bio, iter) {
313 void *kaddr = kmap_atomic(bv.bv_page);
314 bix.data_buf = kaddr + bv.bv_offset;
315 bix.data_size = bv.bv_len;
316 bix.prot_buf = prot_buf;
319 bi->generate_fn(&bix);
321 sectors = bv.bv_len / bi->sector_size;
323 prot_buf += sectors * bi->tuple_size;
324 total += sectors * bi->tuple_size;
325 BUG_ON(total > bio->bi_integrity->bip_size);
327 kunmap_atomic(kaddr);
331 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
334 return bi->tuple_size;
340 * bio_integrity_prep - Prepare bio for integrity I/O
341 * @bio: bio to prepare
343 * Description: Allocates a buffer for integrity metadata, maps the
344 * pages and attaches them to a bio. The bio must have data
345 * direction, target device and start sector set priot to calling. In
346 * the WRITE case, integrity metadata will be generated using the
347 * block device's integrity function. In the READ case, the buffer
348 * will be prepared for DMA and a suitable end_io handler set up.
350 int bio_integrity_prep(struct bio *bio)
352 struct bio_integrity_payload *bip;
353 struct blk_integrity *bi;
354 struct request_queue *q;
356 unsigned long start, end;
357 unsigned int len, nr_pages;
358 unsigned int bytes, offset, i;
359 unsigned int sectors;
361 bi = bdev_get_integrity(bio->bi_bdev);
362 q = bdev_get_queue(bio->bi_bdev);
364 BUG_ON(bio_integrity(bio));
366 sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
368 /* Allocate kernel buffer for protection data */
369 len = sectors * blk_integrity_tuple_size(bi);
370 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
371 if (unlikely(buf == NULL)) {
372 printk(KERN_ERR "could not allocate integrity buffer\n");
376 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
377 start = ((unsigned long) buf) >> PAGE_SHIFT;
378 nr_pages = end - start;
380 /* Allocate bio integrity payload and integrity vectors */
381 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
382 if (unlikely(bip == NULL)) {
383 printk(KERN_ERR "could not allocate data integrity bioset\n");
388 bip->bip_owns_buf = 1;
391 bip->bip_sector = bio->bi_iter.bi_sector;
394 offset = offset_in_page(buf);
395 for (i = 0 ; i < nr_pages ; i++) {
397 bytes = PAGE_SIZE - offset;
405 ret = bio_integrity_add_page(bio, virt_to_page(buf),
419 /* Install custom I/O completion handler if read verify is enabled */
420 if (bio_data_dir(bio) == READ) {
421 bip->bip_end_io = bio->bi_end_io;
422 bio->bi_end_io = bio_integrity_endio;
425 /* Auto-generate integrity metadata if this is a write */
426 if (bio_data_dir(bio) == WRITE)
427 bio_integrity_generate(bio);
431 EXPORT_SYMBOL(bio_integrity_prep);
434 * bio_integrity_verify - Verify integrity metadata for a bio
435 * @bio: bio to verify
437 * Description: This function is called to verify the integrity of a
438 * bio. The data in the bio io_vec is compared to the integrity
439 * metadata returned by the HBA.
441 static int bio_integrity_verify(struct bio *bio)
443 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
444 struct blk_integrity_exchg bix;
446 struct bvec_iter iter;
447 sector_t sector = bio->bi_integrity->bip_sector;
448 unsigned int sectors, total, ret;
449 void *prot_buf = bio->bi_integrity->bip_buf;
452 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
453 bix.sector_size = bi->sector_size;
455 bio_for_each_segment(bv, bio, iter) {
456 void *kaddr = kmap_atomic(bv.bv_page);
457 bix.data_buf = kaddr + bv.bv_offset;
458 bix.data_size = bv.bv_len;
459 bix.prot_buf = prot_buf;
462 ret = bi->verify_fn(&bix);
465 kunmap_atomic(kaddr);
469 sectors = bv.bv_len / bi->sector_size;
471 prot_buf += sectors * bi->tuple_size;
472 total += sectors * bi->tuple_size;
473 BUG_ON(total > bio->bi_integrity->bip_size);
475 kunmap_atomic(kaddr);
482 * bio_integrity_verify_fn - Integrity I/O completion worker
483 * @work: Work struct stored in bio to be verified
485 * Description: This workqueue function is called to complete a READ
486 * request. The function verifies the transferred integrity metadata
487 * and then calls the original bio end_io function.
489 static void bio_integrity_verify_fn(struct work_struct *work)
491 struct bio_integrity_payload *bip =
492 container_of(work, struct bio_integrity_payload, bip_work);
493 struct bio *bio = bip->bip_bio;
496 error = bio_integrity_verify(bio);
498 /* Restore original bio completion handler */
499 bio->bi_end_io = bip->bip_end_io;
500 bio_endio(bio, error);
504 * bio_integrity_endio - Integrity I/O completion function
505 * @bio: Protected bio
506 * @error: Pointer to errno
508 * Description: Completion for integrity I/O
510 * Normally I/O completion is done in interrupt context. However,
511 * verifying I/O integrity is a time-consuming task which must be run
512 * in process context. This function postpones completion
515 void bio_integrity_endio(struct bio *bio, int error)
517 struct bio_integrity_payload *bip = bio->bi_integrity;
519 BUG_ON(bip->bip_bio != bio);
521 /* In case of an I/O error there is no point in verifying the
522 * integrity metadata. Restore original bio end_io handler
526 bio->bi_end_io = bip->bip_end_io;
527 bio_endio(bio, error);
532 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
533 queue_work(kintegrityd_wq, &bip->bip_work);
535 EXPORT_SYMBOL(bio_integrity_endio);
538 * bio_integrity_mark_head - Advance bip_vec skip bytes
539 * @bip: Integrity vector to advance
540 * @skip: Number of bytes to advance it
542 void bio_integrity_mark_head(struct bio_integrity_payload *bip,
548 bip_for_each_vec(iv, bip, i) {
552 } else if (skip >= iv->bv_len) {
554 } else { /* skip < iv->bv_len) */
555 iv->bv_offset += skip;
564 * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long
565 * @bip: Integrity vector to truncate
566 * @len: New length of integrity vector
568 void bio_integrity_mark_tail(struct bio_integrity_payload *bip,
574 bip_for_each_vec(iv, bip, i) {
578 } else if (len >= iv->bv_len) {
580 } else { /* len < iv->bv_len) */
588 * bio_integrity_advance - Advance integrity vector
589 * @bio: bio whose integrity vector to update
590 * @bytes_done: number of data bytes that have been completed
592 * Description: This function calculates how many integrity bytes the
593 * number of completed data bytes correspond to and advances the
594 * integrity vector accordingly.
596 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
598 struct bio_integrity_payload *bip = bio->bi_integrity;
599 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
600 unsigned int nr_sectors;
605 nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9);
606 bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size);
608 EXPORT_SYMBOL(bio_integrity_advance);
611 * bio_integrity_trim - Trim integrity vector
612 * @bio: bio whose integrity vector to update
613 * @offset: offset to first data sector
614 * @sectors: number of data sectors
616 * Description: Used to trim the integrity vector in a cloned bio.
617 * The ivec will be advanced corresponding to 'offset' data sectors
618 * and the length will be truncated corresponding to 'len' data
621 void bio_integrity_trim(struct bio *bio, unsigned int offset,
622 unsigned int sectors)
624 struct bio_integrity_payload *bip = bio->bi_integrity;
625 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
626 unsigned int nr_sectors;
630 BUG_ON(!bio_flagged(bio, BIO_CLONED));
632 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
633 bip->bip_sector = bip->bip_sector + offset;
634 bio_integrity_mark_head(bip, offset * bi->tuple_size);
635 bio_integrity_mark_tail(bip, sectors * bi->tuple_size);
637 EXPORT_SYMBOL(bio_integrity_trim);
640 * bio_integrity_split - Split integrity metadata
641 * @bio: Protected bio
642 * @bp: Resulting bio_pair
645 * Description: Splits an integrity page into a bio_pair.
647 void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
649 struct blk_integrity *bi;
650 struct bio_integrity_payload *bip = bio->bi_integrity;
651 unsigned int nr_sectors;
653 if (bio_integrity(bio) == 0)
656 bi = bdev_get_integrity(bio->bi_bdev);
658 BUG_ON(bip->bip_vcnt != 1);
660 nr_sectors = bio_integrity_hw_sectors(bi, sectors);
662 bp->bio1.bi_integrity = &bp->bip1;
663 bp->bio2.bi_integrity = &bp->bip2;
665 bp->iv1 = bip->bip_vec[bip->bip_idx];
666 bp->iv2 = bip->bip_vec[bip->bip_idx];
668 bp->bip1.bip_vec = &bp->iv1;
669 bp->bip2.bip_vec = &bp->iv2;
671 bp->iv1.bv_len = sectors * bi->tuple_size;
672 bp->iv2.bv_offset += sectors * bi->tuple_size;
673 bp->iv2.bv_len -= sectors * bi->tuple_size;
675 bp->bip1.bip_sector = bio->bi_integrity->bip_sector;
676 bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors;
678 bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1;
679 bp->bip1.bip_idx = bp->bip2.bip_idx = 0;
681 EXPORT_SYMBOL(bio_integrity_split);
684 * bio_integrity_clone - Callback for cloning bios with integrity metadata
686 * @bio_src: Original bio
687 * @gfp_mask: Memory allocation mask
689 * Description: Called to allocate a bip when cloning a bio
691 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
694 struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
695 struct bio_integrity_payload *bip;
697 BUG_ON(bip_src == NULL);
699 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
704 memcpy(bip->bip_vec, bip_src->bip_vec,
705 bip_src->bip_vcnt * sizeof(struct bio_vec));
707 bip->bip_sector = bip_src->bip_sector;
708 bip->bip_vcnt = bip_src->bip_vcnt;
709 bip->bip_idx = bip_src->bip_idx;
713 EXPORT_SYMBOL(bio_integrity_clone);
715 int bioset_integrity_create(struct bio_set *bs, int pool_size)
717 if (bs->bio_integrity_pool)
720 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
721 if (!bs->bio_integrity_pool)
724 bs->bvec_integrity_pool = biovec_create_pool(bs, pool_size);
725 if (!bs->bvec_integrity_pool) {
726 mempool_destroy(bs->bio_integrity_pool);
732 EXPORT_SYMBOL(bioset_integrity_create);
734 void bioset_integrity_free(struct bio_set *bs)
736 if (bs->bio_integrity_pool)
737 mempool_destroy(bs->bio_integrity_pool);
739 if (bs->bvec_integrity_pool)
740 mempool_destroy(bs->bvec_integrity_pool);
742 EXPORT_SYMBOL(bioset_integrity_free);
744 void __init bio_integrity_init(void)
747 * kintegrityd won't block much but may burn a lot of CPU cycles.
748 * Make it highpri CPU intensive wq with max concurrency of 1.
750 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
751 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
753 panic("Failed to create kintegrityd\n");
755 bip_slab = kmem_cache_create("bio_integrity_payload",
756 sizeof(struct bio_integrity_payload) +
757 sizeof(struct bio_vec) * BIP_INLINE_VECS,
758 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
760 panic("Failed to create slab\n");