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
);
117 static inline unsigned int bip_integrity_vecs(struct bio_integrity_payload
*bip
)
119 if (bip
->bip_slab
== BIO_POOL_NONE
)
120 return BIP_INLINE_VECS
;
122 return bvec_nr_vecs(bip
->bip_slab
);
126 * bio_integrity_add_page - Attach integrity metadata
127 * @bio: bio to update
128 * @page: page containing integrity metadata
129 * @len: number of bytes of integrity metadata in page
130 * @offset: start offset within page
132 * Description: Attach a page containing integrity metadata to bio.
134 int bio_integrity_add_page(struct bio
*bio
, struct page
*page
,
135 unsigned int len
, unsigned int offset
)
137 struct bio_integrity_payload
*bip
= bio
->bi_integrity
;
140 if (bip
->bip_vcnt
>= bip_integrity_vecs(bip
)) {
141 printk(KERN_ERR
"%s: bip_vec full\n", __func__
);
145 iv
= bip
->bip_vec
+ bip
->bip_vcnt
;
149 iv
->bv_offset
= offset
;
154 EXPORT_SYMBOL(bio_integrity_add_page
);
156 static int bdev_integrity_enabled(struct block_device
*bdev
, int rw
)
158 struct blk_integrity
*bi
= bdev_get_integrity(bdev
);
163 if (rw
== READ
&& bi
->verify_fn
!= NULL
&&
164 (bi
->flags
& INTEGRITY_FLAG_READ
))
167 if (rw
== WRITE
&& bi
->generate_fn
!= NULL
&&
168 (bi
->flags
& INTEGRITY_FLAG_WRITE
))
175 * bio_integrity_enabled - Check whether integrity can be passed
178 * Description: Determines whether bio_integrity_prep() can be called
179 * on this bio or not. bio data direction and target device must be
180 * set prior to calling. The functions honors the write_generate and
181 * read_verify flags in sysfs.
183 int bio_integrity_enabled(struct bio
*bio
)
185 /* Already protected? */
186 if (bio_integrity(bio
))
189 return bdev_integrity_enabled(bio
->bi_bdev
, bio_data_dir(bio
));
191 EXPORT_SYMBOL(bio_integrity_enabled
);
194 * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
195 * @bi: blk_integrity profile for device
196 * @sectors: Number of 512 sectors to convert
198 * Description: The block layer calculates everything in 512 byte
199 * sectors but integrity metadata is done in terms of the hardware
200 * sector size of the storage device. Convert the block layer sectors
201 * to physical sectors.
203 static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity
*bi
,
204 unsigned int sectors
)
206 /* At this point there are only 512b or 4096b DIF/EPP devices */
207 if (bi
->sector_size
== 4096)
208 return sectors
>>= 3;
213 static inline unsigned int bio_integrity_bytes(struct blk_integrity
*bi
,
214 unsigned int sectors
)
216 return bio_integrity_hw_sectors(bi
, sectors
) * bi
->tuple_size
;
220 * bio_integrity_tag_size - Retrieve integrity tag space
221 * @bio: bio to inspect
223 * Description: Returns the maximum number of tag bytes that can be
224 * attached to this bio. Filesystems can use this to determine how
225 * much metadata to attach to an I/O.
227 unsigned int bio_integrity_tag_size(struct bio
*bio
)
229 struct blk_integrity
*bi
= bdev_get_integrity(bio
->bi_bdev
);
231 BUG_ON(bio
->bi_iter
.bi_size
== 0);
233 return bi
->tag_size
* (bio
->bi_iter
.bi_size
/ bi
->sector_size
);
235 EXPORT_SYMBOL(bio_integrity_tag_size
);
237 static int bio_integrity_tag(struct bio
*bio
, void *tag_buf
, unsigned int len
,
240 struct bio_integrity_payload
*bip
= bio
->bi_integrity
;
241 struct blk_integrity
*bi
= bdev_get_integrity(bio
->bi_bdev
);
242 unsigned int nr_sectors
;
244 BUG_ON(bip
->bip_buf
== NULL
);
246 if (bi
->tag_size
== 0)
249 nr_sectors
= bio_integrity_hw_sectors(bi
,
250 DIV_ROUND_UP(len
, bi
->tag_size
));
252 if (nr_sectors
* bi
->tuple_size
> bip
->bip_iter
.bi_size
) {
253 printk(KERN_ERR
"%s: tag too big for bio: %u > %u\n", __func__
,
254 nr_sectors
* bi
->tuple_size
, bip
->bip_iter
.bi_size
);
259 bi
->set_tag_fn(bip
->bip_buf
, tag_buf
, nr_sectors
);
261 bi
->get_tag_fn(bip
->bip_buf
, tag_buf
, nr_sectors
);
267 * bio_integrity_set_tag - Attach a tag buffer to a bio
268 * @bio: bio to attach buffer to
269 * @tag_buf: Pointer to a buffer containing tag data
270 * @len: Length of the included buffer
272 * Description: Use this function to tag a bio by leveraging the extra
273 * space provided by devices formatted with integrity protection. The
274 * size of the integrity buffer must be <= to the size reported by
275 * bio_integrity_tag_size().
277 int bio_integrity_set_tag(struct bio
*bio
, void *tag_buf
, unsigned int len
)
279 BUG_ON(bio_data_dir(bio
) != WRITE
);
281 return bio_integrity_tag(bio
, tag_buf
, len
, 1);
283 EXPORT_SYMBOL(bio_integrity_set_tag
);
286 * bio_integrity_get_tag - Retrieve a tag buffer from a bio
287 * @bio: bio to retrieve buffer from
288 * @tag_buf: Pointer to a buffer for the tag data
289 * @len: Length of the target buffer
291 * Description: Use this function to retrieve the tag buffer from a
292 * completed I/O. The size of the integrity buffer must be <= to the
293 * size reported by bio_integrity_tag_size().
295 int bio_integrity_get_tag(struct bio
*bio
, void *tag_buf
, unsigned int len
)
297 BUG_ON(bio_data_dir(bio
) != READ
);
299 return bio_integrity_tag(bio
, tag_buf
, len
, 0);
301 EXPORT_SYMBOL(bio_integrity_get_tag
);
304 * bio_integrity_generate_verify - Generate/verify integrity metadata for a bio
305 * @bio: bio to generate/verify integrity metadata for
306 * @operate: operate number, 1 for generate, 0 for verify
308 static int bio_integrity_generate_verify(struct bio
*bio
, int operate
)
310 struct blk_integrity
*bi
= bdev_get_integrity(bio
->bi_bdev
);
311 struct blk_integrity_exchg bix
;
313 struct bvec_iter iter
;
315 unsigned int sectors
, ret
= 0;
316 void *prot_buf
= bio
->bi_integrity
->bip_buf
;
319 sector
= bio
->bi_iter
.bi_sector
;
321 sector
= bio
->bi_integrity
->bip_iter
.bi_sector
;
323 bix
.disk_name
= bio
->bi_bdev
->bd_disk
->disk_name
;
324 bix
.sector_size
= bi
->sector_size
;
326 bio_for_each_segment(bv
, bio
, iter
) {
327 void *kaddr
= kmap_atomic(bv
.bv_page
);
328 bix
.data_buf
= kaddr
+ bv
.bv_offset
;
329 bix
.data_size
= bv
.bv_len
;
330 bix
.prot_buf
= prot_buf
;
334 bi
->generate_fn(&bix
);
336 ret
= bi
->verify_fn(&bix
);
338 kunmap_atomic(kaddr
);
343 sectors
= bv
.bv_len
/ bi
->sector_size
;
345 prot_buf
+= sectors
* bi
->tuple_size
;
347 kunmap_atomic(kaddr
);
353 * bio_integrity_generate - Generate integrity metadata for a bio
354 * @bio: bio to generate integrity metadata for
356 * Description: Generates integrity metadata for a bio by calling the
357 * block device's generation callback function. The bio must have a
358 * bip attached with enough room to accommodate the generated
359 * integrity metadata.
361 static void bio_integrity_generate(struct bio
*bio
)
363 bio_integrity_generate_verify(bio
, 1);
366 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity
*bi
)
369 return bi
->tuple_size
;
375 * bio_integrity_prep - Prepare bio for integrity I/O
376 * @bio: bio to prepare
378 * Description: Allocates a buffer for integrity metadata, maps the
379 * pages and attaches them to a bio. The bio must have data
380 * direction, target device and start sector set priot to calling. In
381 * the WRITE case, integrity metadata will be generated using the
382 * block device's integrity function. In the READ case, the buffer
383 * will be prepared for DMA and a suitable end_io handler set up.
385 int bio_integrity_prep(struct bio
*bio
)
387 struct bio_integrity_payload
*bip
;
388 struct blk_integrity
*bi
;
389 struct request_queue
*q
;
391 unsigned long start
, end
;
392 unsigned int len
, nr_pages
;
393 unsigned int bytes
, offset
, i
;
394 unsigned int sectors
;
396 bi
= bdev_get_integrity(bio
->bi_bdev
);
397 q
= bdev_get_queue(bio
->bi_bdev
);
399 BUG_ON(bio_integrity(bio
));
401 sectors
= bio_integrity_hw_sectors(bi
, bio_sectors(bio
));
403 /* Allocate kernel buffer for protection data */
404 len
= sectors
* blk_integrity_tuple_size(bi
);
405 buf
= kmalloc(len
, GFP_NOIO
| q
->bounce_gfp
);
406 if (unlikely(buf
== NULL
)) {
407 printk(KERN_ERR
"could not allocate integrity buffer\n");
411 end
= (((unsigned long) buf
) + len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
412 start
= ((unsigned long) buf
) >> PAGE_SHIFT
;
413 nr_pages
= end
- start
;
415 /* Allocate bio integrity payload and integrity vectors */
416 bip
= bio_integrity_alloc(bio
, GFP_NOIO
, nr_pages
);
417 if (unlikely(bip
== NULL
)) {
418 printk(KERN_ERR
"could not allocate data integrity bioset\n");
423 bip
->bip_owns_buf
= 1;
425 bip
->bip_iter
.bi_size
= len
;
426 bip
->bip_iter
.bi_sector
= bio
->bi_iter
.bi_sector
;
429 offset
= offset_in_page(buf
);
430 for (i
= 0 ; i
< nr_pages
; i
++) {
432 bytes
= PAGE_SIZE
- offset
;
440 ret
= bio_integrity_add_page(bio
, virt_to_page(buf
),
454 /* Install custom I/O completion handler if read verify is enabled */
455 if (bio_data_dir(bio
) == READ
) {
456 bip
->bip_end_io
= bio
->bi_end_io
;
457 bio
->bi_end_io
= bio_integrity_endio
;
460 /* Auto-generate integrity metadata if this is a write */
461 if (bio_data_dir(bio
) == WRITE
)
462 bio_integrity_generate(bio
);
466 EXPORT_SYMBOL(bio_integrity_prep
);
469 * bio_integrity_verify - Verify integrity metadata for a bio
470 * @bio: bio to verify
472 * Description: This function is called to verify the integrity of a
473 * bio. The data in the bio io_vec is compared to the integrity
474 * metadata returned by the HBA.
476 static int bio_integrity_verify(struct bio
*bio
)
478 return bio_integrity_generate_verify(bio
, 0);
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_nodec(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_advance - Advance integrity vector
539 * @bio: bio whose integrity vector to update
540 * @bytes_done: number of data bytes that have been completed
542 * Description: This function calculates how many integrity bytes the
543 * number of completed data bytes correspond to and advances the
544 * integrity vector accordingly.
546 void bio_integrity_advance(struct bio
*bio
, unsigned int bytes_done
)
548 struct bio_integrity_payload
*bip
= bio
->bi_integrity
;
549 struct blk_integrity
*bi
= bdev_get_integrity(bio
->bi_bdev
);
550 unsigned bytes
= bio_integrity_bytes(bi
, bytes_done
>> 9);
552 bvec_iter_advance(bip
->bip_vec
, &bip
->bip_iter
, bytes
);
554 EXPORT_SYMBOL(bio_integrity_advance
);
557 * bio_integrity_trim - Trim integrity vector
558 * @bio: bio whose integrity vector to update
559 * @offset: offset to first data sector
560 * @sectors: number of data sectors
562 * Description: Used to trim the integrity vector in a cloned bio.
563 * The ivec will be advanced corresponding to 'offset' data sectors
564 * and the length will be truncated corresponding to 'len' data
567 void bio_integrity_trim(struct bio
*bio
, unsigned int offset
,
568 unsigned int sectors
)
570 struct bio_integrity_payload
*bip
= bio
->bi_integrity
;
571 struct blk_integrity
*bi
= bdev_get_integrity(bio
->bi_bdev
);
573 bio_integrity_advance(bio
, offset
<< 9);
574 bip
->bip_iter
.bi_size
= bio_integrity_bytes(bi
, sectors
);
576 EXPORT_SYMBOL(bio_integrity_trim
);
579 * bio_integrity_clone - Callback for cloning bios with integrity metadata
581 * @bio_src: Original bio
582 * @gfp_mask: Memory allocation mask
584 * Description: Called to allocate a bip when cloning a bio
586 int bio_integrity_clone(struct bio
*bio
, struct bio
*bio_src
,
589 struct bio_integrity_payload
*bip_src
= bio_src
->bi_integrity
;
590 struct bio_integrity_payload
*bip
;
592 BUG_ON(bip_src
== NULL
);
594 bip
= bio_integrity_alloc(bio
, gfp_mask
, bip_src
->bip_vcnt
);
599 memcpy(bip
->bip_vec
, bip_src
->bip_vec
,
600 bip_src
->bip_vcnt
* sizeof(struct bio_vec
));
602 bip
->bip_vcnt
= bip_src
->bip_vcnt
;
603 bip
->bip_iter
= bip_src
->bip_iter
;
607 EXPORT_SYMBOL(bio_integrity_clone
);
609 int bioset_integrity_create(struct bio_set
*bs
, int pool_size
)
611 if (bs
->bio_integrity_pool
)
614 bs
->bio_integrity_pool
= mempool_create_slab_pool(pool_size
, bip_slab
);
615 if (!bs
->bio_integrity_pool
)
618 bs
->bvec_integrity_pool
= biovec_create_pool(bs
, pool_size
);
619 if (!bs
->bvec_integrity_pool
) {
620 mempool_destroy(bs
->bio_integrity_pool
);
626 EXPORT_SYMBOL(bioset_integrity_create
);
628 void bioset_integrity_free(struct bio_set
*bs
)
630 if (bs
->bio_integrity_pool
)
631 mempool_destroy(bs
->bio_integrity_pool
);
633 if (bs
->bvec_integrity_pool
)
634 mempool_destroy(bs
->bvec_integrity_pool
);
636 EXPORT_SYMBOL(bioset_integrity_free
);
638 void __init
bio_integrity_init(void)
641 * kintegrityd won't block much but may burn a lot of CPU cycles.
642 * Make it highpri CPU intensive wq with max concurrency of 1.
644 kintegrityd_wq
= alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM
|
645 WQ_HIGHPRI
| WQ_CPU_INTENSIVE
, 1);
647 panic("Failed to create kintegrityd\n");
649 bip_slab
= kmem_cache_create("bio_integrity_payload",
650 sizeof(struct bio_integrity_payload
) +
651 sizeof(struct bio_vec
) * BIP_INLINE_VECS
,
652 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
654 panic("Failed to create slab\n");
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