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);
73 bip->bip_max_vcnt = bvec_nr_vecs(idx);
75 bip->bip_vec = bip->bip_inline_vecs;
76 bip->bip_max_vcnt = inline_vecs;
81 bio->bi_integrity = bip;
82 bio->bi_rw |= REQ_INTEGRITY;
86 mempool_free(bip, bs->bio_integrity_pool);
89 EXPORT_SYMBOL(bio_integrity_alloc);
92 * bio_integrity_free - Free bio integrity payload
93 * @bio: bio containing bip to be freed
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)
100 struct bio_integrity_payload *bip = bio_integrity(bio);
101 struct bio_set *bs = bio->bi_pool;
103 if (bip->bip_owns_buf)
104 kfree(page_address(bip->bip_vec->bv_page) +
105 bip->bip_vec->bv_offset);
108 if (bip->bip_slab != BIO_POOL_NONE)
109 bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
112 mempool_free(bip, bs->bio_integrity_pool);
117 bio->bi_integrity = NULL;
119 EXPORT_SYMBOL(bio_integrity_free);
122 * bio_integrity_add_page - Attach integrity metadata
123 * @bio: bio to update
124 * @page: page containing integrity metadata
125 * @len: number of bytes of integrity metadata in page
126 * @offset: start offset within page
128 * Description: Attach a page containing integrity metadata to bio.
130 int bio_integrity_add_page(struct bio *bio, struct page *page,
131 unsigned int len, unsigned int offset)
133 struct bio_integrity_payload *bip = bio_integrity(bio);
136 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
137 printk(KERN_ERR "%s: bip_vec full\n", __func__);
141 iv = bip->bip_vec + bip->bip_vcnt;
145 iv->bv_offset = offset;
150 EXPORT_SYMBOL(bio_integrity_add_page);
153 * bio_integrity_enabled - Check whether integrity can be passed
156 * Description: Determines whether bio_integrity_prep() can be called
157 * on this bio or not. bio data direction and target device must be
158 * set prior to calling. The functions honors the write_generate and
159 * read_verify flags in sysfs.
161 bool bio_integrity_enabled(struct bio *bio)
163 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
168 /* Already protected? */
169 if (bio_integrity(bio))
175 if (bio_data_dir(bio) == READ && bi->verify_fn != NULL &&
176 (bi->flags & INTEGRITY_FLAG_READ))
179 if (bio_data_dir(bio) == WRITE && bi->generate_fn != NULL &&
180 (bi->flags & INTEGRITY_FLAG_WRITE))
185 EXPORT_SYMBOL(bio_integrity_enabled);
188 * bio_integrity_intervals - Return number of integrity intervals for a bio
189 * @bi: blk_integrity profile for device
190 * @sectors: Size of the bio in 512-byte sectors
192 * Description: The block layer calculates everything in 512 byte
193 * sectors but integrity metadata is done in terms of the data integrity
194 * interval size of the storage device. Convert the block layer sectors
195 * to the appropriate number of integrity intervals.
197 static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
198 unsigned int sectors)
200 return sectors >> (ilog2(bi->interval) - 9);
203 static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
204 unsigned int sectors)
206 return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
210 * bio_integrity_generate_verify - Generate/verify integrity metadata for a bio
211 * @bio: bio to generate/verify integrity metadata for
212 * @operate: operate number, 1 for generate, 0 for verify
214 static int bio_integrity_generate_verify(struct bio *bio, int operate)
216 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
217 struct blk_integrity_exchg bix;
219 struct bio_integrity_payload *bip = bio_integrity(bio);
221 unsigned int intervals, ret = 0, i;
222 void *prot_buf = page_address(bip->bip_vec->bv_page) +
223 bip->bip_vec->bv_offset;
226 seed = bio->bi_iter.bi_sector;
228 seed = bip->bip_iter.bi_sector;
230 bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
231 bix.interval = bi->interval;
233 bio_for_each_segment_all(bv, bio, i) {
234 void *kaddr = kmap_atomic(bv->bv_page);
235 bix.data_buf = kaddr + bv->bv_offset;
236 bix.data_size = bv->bv_len;
237 bix.prot_buf = prot_buf;
241 bi->generate_fn(&bix);
243 ret = bi->verify_fn(&bix);
245 kunmap_atomic(kaddr);
250 intervals = bv->bv_len / bi->interval;
252 prot_buf += intervals * bi->tuple_size;
254 kunmap_atomic(kaddr);
260 * bio_integrity_generate - Generate integrity metadata for a bio
261 * @bio: bio to generate integrity metadata for
263 * Description: Generates integrity metadata for a bio by calling the
264 * block device's generation callback function. The bio must have a
265 * bip attached with enough room to accommodate the generated
266 * integrity metadata.
268 static void bio_integrity_generate(struct bio *bio)
270 bio_integrity_generate_verify(bio, 1);
274 * bio_integrity_prep - Prepare bio for integrity I/O
275 * @bio: bio to prepare
277 * Description: Allocates a buffer for integrity metadata, maps the
278 * pages and attaches them to a bio. The bio must have data
279 * direction, target device and start sector set priot to calling. In
280 * the WRITE case, integrity metadata will be generated using the
281 * block device's integrity function. In the READ case, the buffer
282 * will be prepared for DMA and a suitable end_io handler set up.
284 int bio_integrity_prep(struct bio *bio)
286 struct bio_integrity_payload *bip;
287 struct blk_integrity *bi;
288 struct request_queue *q;
290 unsigned long start, end;
291 unsigned int len, nr_pages;
292 unsigned int bytes, offset, i;
293 unsigned int intervals;
295 bi = bdev_get_integrity(bio->bi_bdev);
296 q = bdev_get_queue(bio->bi_bdev);
298 BUG_ON(bio_integrity(bio));
300 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
302 /* Allocate kernel buffer for protection data */
303 len = intervals * bi->tuple_size;
304 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
305 if (unlikely(buf == NULL)) {
306 printk(KERN_ERR "could not allocate integrity buffer\n");
310 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
311 start = ((unsigned long) buf) >> PAGE_SHIFT;
312 nr_pages = end - start;
314 /* Allocate bio integrity payload and integrity vectors */
315 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
316 if (unlikely(bip == NULL)) {
317 printk(KERN_ERR "could not allocate data integrity bioset\n");
322 bip->bip_owns_buf = 1;
323 bip->bip_iter.bi_size = len;
324 bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
327 offset = offset_in_page(buf);
328 for (i = 0 ; i < nr_pages ; i++) {
330 bytes = PAGE_SIZE - offset;
338 ret = bio_integrity_add_page(bio, virt_to_page(buf),
352 /* Install custom I/O completion handler if read verify is enabled */
353 if (bio_data_dir(bio) == READ) {
354 bip->bip_end_io = bio->bi_end_io;
355 bio->bi_end_io = bio_integrity_endio;
358 /* Auto-generate integrity metadata if this is a write */
359 if (bio_data_dir(bio) == WRITE)
360 bio_integrity_generate(bio);
364 EXPORT_SYMBOL(bio_integrity_prep);
367 * bio_integrity_verify - Verify integrity metadata for a bio
368 * @bio: bio to verify
370 * Description: This function is called to verify the integrity of a
371 * bio. The data in the bio io_vec is compared to the integrity
372 * metadata returned by the HBA.
374 static int bio_integrity_verify(struct bio *bio)
376 return bio_integrity_generate_verify(bio, 0);
380 * bio_integrity_verify_fn - Integrity I/O completion worker
381 * @work: Work struct stored in bio to be verified
383 * Description: This workqueue function is called to complete a READ
384 * request. The function verifies the transferred integrity metadata
385 * and then calls the original bio end_io function.
387 static void bio_integrity_verify_fn(struct work_struct *work)
389 struct bio_integrity_payload *bip =
390 container_of(work, struct bio_integrity_payload, bip_work);
391 struct bio *bio = bip->bip_bio;
394 error = bio_integrity_verify(bio);
396 /* Restore original bio completion handler */
397 bio->bi_end_io = bip->bip_end_io;
398 bio_endio_nodec(bio, error);
402 * bio_integrity_endio - Integrity I/O completion function
403 * @bio: Protected bio
404 * @error: Pointer to errno
406 * Description: Completion for integrity I/O
408 * Normally I/O completion is done in interrupt context. However,
409 * verifying I/O integrity is a time-consuming task which must be run
410 * in process context. This function postpones completion
413 void bio_integrity_endio(struct bio *bio, int error)
415 struct bio_integrity_payload *bip = bio_integrity(bio);
417 BUG_ON(bip->bip_bio != bio);
419 /* In case of an I/O error there is no point in verifying the
420 * integrity metadata. Restore original bio end_io handler
424 bio->bi_end_io = bip->bip_end_io;
425 bio_endio_nodec(bio, error);
430 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
431 queue_work(kintegrityd_wq, &bip->bip_work);
433 EXPORT_SYMBOL(bio_integrity_endio);
436 * bio_integrity_advance - Advance integrity vector
437 * @bio: bio whose integrity vector to update
438 * @bytes_done: number of data bytes that have been completed
440 * Description: This function calculates how many integrity bytes the
441 * number of completed data bytes correspond to and advances the
442 * integrity vector accordingly.
444 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
446 struct bio_integrity_payload *bip = bio_integrity(bio);
447 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
448 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
450 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
452 EXPORT_SYMBOL(bio_integrity_advance);
455 * bio_integrity_trim - Trim integrity vector
456 * @bio: bio whose integrity vector to update
457 * @offset: offset to first data sector
458 * @sectors: number of data sectors
460 * Description: Used to trim the integrity vector in a cloned bio.
461 * The ivec will be advanced corresponding to 'offset' data sectors
462 * and the length will be truncated corresponding to 'len' data
465 void bio_integrity_trim(struct bio *bio, unsigned int offset,
466 unsigned int sectors)
468 struct bio_integrity_payload *bip = bio_integrity(bio);
469 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
471 bio_integrity_advance(bio, offset << 9);
472 bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
474 EXPORT_SYMBOL(bio_integrity_trim);
477 * bio_integrity_clone - Callback for cloning bios with integrity metadata
479 * @bio_src: Original bio
480 * @gfp_mask: Memory allocation mask
482 * Description: Called to allocate a bip when cloning a bio
484 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
487 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
488 struct bio_integrity_payload *bip;
490 BUG_ON(bip_src == NULL);
492 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
497 memcpy(bip->bip_vec, bip_src->bip_vec,
498 bip_src->bip_vcnt * sizeof(struct bio_vec));
500 bip->bip_vcnt = bip_src->bip_vcnt;
501 bip->bip_iter = bip_src->bip_iter;
505 EXPORT_SYMBOL(bio_integrity_clone);
507 int bioset_integrity_create(struct bio_set *bs, int pool_size)
509 if (bs->bio_integrity_pool)
512 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
513 if (!bs->bio_integrity_pool)
516 bs->bvec_integrity_pool = biovec_create_pool(pool_size);
517 if (!bs->bvec_integrity_pool) {
518 mempool_destroy(bs->bio_integrity_pool);
524 EXPORT_SYMBOL(bioset_integrity_create);
526 void bioset_integrity_free(struct bio_set *bs)
528 if (bs->bio_integrity_pool)
529 mempool_destroy(bs->bio_integrity_pool);
531 if (bs->bvec_integrity_pool)
532 mempool_destroy(bs->bvec_integrity_pool);
534 EXPORT_SYMBOL(bioset_integrity_free);
536 void __init bio_integrity_init(void)
539 * kintegrityd won't block much but may burn a lot of CPU cycles.
540 * Make it highpri CPU intensive wq with max concurrency of 1.
542 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
543 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
545 panic("Failed to create kintegrityd\n");
547 bip_slab = kmem_cache_create("bio_integrity_payload",
548 sizeof(struct bio_integrity_payload) +
549 sizeof(struct bio_vec) * BIP_INLINE_VECS,
550 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
552 panic("Failed to create slab\n");