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>
31 #define BIP_INLINE_VECS 4
33 static struct kmem_cache *bip_slab;
34 static struct workqueue_struct *kintegrityd_wq;
36 void blk_flush_integrity(void)
38 flush_workqueue(kintegrityd_wq);
42 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
43 * @bio: bio to attach integrity metadata to
44 * @gfp_mask: Memory allocation mask
45 * @nr_vecs: Number of integrity metadata scatter-gather elements
47 * Description: This function prepares a bio for attaching integrity
48 * metadata. nr_vecs specifies the maximum number of pages containing
49 * integrity metadata that can be attached.
51 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
55 struct bio_integrity_payload *bip;
56 struct bio_set *bs = bio->bi_pool;
59 if (!bs || !bs->bio_integrity_pool) {
60 bip = kmalloc(sizeof(struct bio_integrity_payload) +
61 sizeof(struct bio_vec) * nr_vecs, gfp_mask);
62 inline_vecs = nr_vecs;
64 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
65 inline_vecs = BIP_INLINE_VECS;
69 return ERR_PTR(-ENOMEM);
71 memset(bip, 0, sizeof(*bip));
73 if (nr_vecs > inline_vecs) {
74 unsigned long idx = 0;
76 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
77 bs->bvec_integrity_pool);
80 bip->bip_max_vcnt = bvec_nr_vecs(idx);
83 bip->bip_vec = bip->bip_inline_vecs;
84 bip->bip_max_vcnt = inline_vecs;
88 bio->bi_integrity = bip;
89 bio->bi_opf |= REQ_INTEGRITY;
93 mempool_free(bip, bs->bio_integrity_pool);
94 return ERR_PTR(-ENOMEM);
96 EXPORT_SYMBOL(bio_integrity_alloc);
99 * bio_integrity_free - Free bio integrity payload
100 * @bio: bio containing bip to be freed
102 * Description: Used to free the integrity portion of a bio. Usually
103 * called from bio_free().
105 void bio_integrity_free(struct bio *bio)
107 struct bio_integrity_payload *bip = bio_integrity(bio);
108 struct bio_set *bs = bio->bi_pool;
110 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
111 kfree(page_address(bip->bip_vec->bv_page) +
112 bip->bip_vec->bv_offset);
114 if (bs && bs->bio_integrity_pool) {
115 bvec_free(bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab);
117 mempool_free(bip, bs->bio_integrity_pool);
122 bio->bi_integrity = NULL;
124 EXPORT_SYMBOL(bio_integrity_free);
127 * bio_integrity_add_page - Attach integrity metadata
128 * @bio: bio to update
129 * @page: page containing integrity metadata
130 * @len: number of bytes of integrity metadata in page
131 * @offset: start offset within page
133 * Description: Attach a page containing integrity metadata to bio.
135 int bio_integrity_add_page(struct bio *bio, struct page *page,
136 unsigned int len, unsigned int offset)
138 struct bio_integrity_payload *bip = bio_integrity(bio);
141 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
142 printk(KERN_ERR "%s: bip_vec full\n", __func__);
146 iv = bip->bip_vec + bip->bip_vcnt;
149 bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
150 &bip->bip_vec[bip->bip_vcnt - 1], offset))
155 iv->bv_offset = offset;
160 EXPORT_SYMBOL(bio_integrity_add_page);
163 * bio_integrity_enabled - Check whether integrity can be passed
166 * Description: Determines whether bio_integrity_prep() can be called
167 * on this bio or not. bio data direction and target device must be
168 * set prior to calling. The functions honors the write_generate and
169 * read_verify flags in sysfs.
171 bool bio_integrity_enabled(struct bio *bio)
173 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
178 /* Already protected? */
179 if (bio_integrity(bio))
185 if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
186 (bi->flags & BLK_INTEGRITY_VERIFY))
189 if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
190 (bi->flags & BLK_INTEGRITY_GENERATE))
195 EXPORT_SYMBOL(bio_integrity_enabled);
198 * bio_integrity_intervals - Return number of integrity intervals for a bio
199 * @bi: blk_integrity profile for device
200 * @sectors: Size of the bio in 512-byte sectors
202 * Description: The block layer calculates everything in 512 byte
203 * sectors but integrity metadata is done in terms of the data integrity
204 * interval size of the storage device. Convert the block layer sectors
205 * to the appropriate number of integrity intervals.
207 static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
208 unsigned int sectors)
210 return sectors >> (bi->interval_exp - 9);
213 static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
214 unsigned int sectors)
216 return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
220 * bio_integrity_process - Process integrity metadata for a bio
221 * @bio: bio to generate/verify integrity metadata for
222 * @proc_fn: Pointer to the relevant processing function
224 static int bio_integrity_process(struct bio *bio,
225 integrity_processing_fn *proc_fn)
227 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
228 struct blk_integrity_iter iter;
229 struct bvec_iter bviter;
231 struct bio_integrity_payload *bip = bio_integrity(bio);
232 unsigned int ret = 0;
233 void *prot_buf = page_address(bip->bip_vec->bv_page) +
234 bip->bip_vec->bv_offset;
236 iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
237 iter.interval = 1 << bi->interval_exp;
238 iter.seed = bip_get_seed(bip);
239 iter.prot_buf = prot_buf;
241 bio_for_each_segment(bv, bio, bviter) {
242 void *kaddr = kmap_atomic(bv.bv_page);
244 iter.data_buf = kaddr + bv.bv_offset;
245 iter.data_size = bv.bv_len;
247 ret = proc_fn(&iter);
249 kunmap_atomic(kaddr);
253 kunmap_atomic(kaddr);
259 * bio_integrity_prep - Prepare bio for integrity I/O
260 * @bio: bio to prepare
262 * Description: Allocates a buffer for integrity metadata, maps the
263 * pages and attaches them to a bio. The bio must have data
264 * direction, target device and start sector set priot to calling. In
265 * the WRITE case, integrity metadata will be generated using the
266 * block device's integrity function. In the READ case, the buffer
267 * will be prepared for DMA and a suitable end_io handler set up.
269 int bio_integrity_prep(struct bio *bio)
271 struct bio_integrity_payload *bip;
272 struct blk_integrity *bi;
273 struct request_queue *q;
275 unsigned long start, end;
276 unsigned int len, nr_pages;
277 unsigned int bytes, offset, i;
278 unsigned int intervals;
280 bi = bdev_get_integrity(bio->bi_bdev);
281 q = bdev_get_queue(bio->bi_bdev);
283 BUG_ON(bio_integrity(bio));
285 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
287 /* Allocate kernel buffer for protection data */
288 len = intervals * bi->tuple_size;
289 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
290 if (unlikely(buf == NULL)) {
291 printk(KERN_ERR "could not allocate integrity buffer\n");
295 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
296 start = ((unsigned long) buf) >> PAGE_SHIFT;
297 nr_pages = end - start;
299 /* Allocate bio integrity payload and integrity vectors */
300 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
302 printk(KERN_ERR "could not allocate data integrity bioset\n");
307 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
308 bip->bip_iter.bi_size = len;
309 bip_set_seed(bip, bio->bi_iter.bi_sector);
311 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
312 bip->bip_flags |= BIP_IP_CHECKSUM;
315 offset = offset_in_page(buf);
316 for (i = 0 ; i < nr_pages ; i++) {
318 bytes = PAGE_SIZE - offset;
326 ret = bio_integrity_add_page(bio, virt_to_page(buf),
340 /* Install custom I/O completion handler if read verify is enabled */
341 if (bio_data_dir(bio) == READ) {
342 bip->bip_end_io = bio->bi_end_io;
343 bio->bi_end_io = bio_integrity_endio;
346 /* Auto-generate integrity metadata if this is a write */
347 if (bio_data_dir(bio) == WRITE)
348 bio_integrity_process(bio, bi->profile->generate_fn);
352 EXPORT_SYMBOL(bio_integrity_prep);
355 * bio_integrity_verify_fn - Integrity I/O completion worker
356 * @work: Work struct stored in bio to be verified
358 * Description: This workqueue function is called to complete a READ
359 * request. The function verifies the transferred integrity metadata
360 * and then calls the original bio end_io function.
362 static void bio_integrity_verify_fn(struct work_struct *work)
364 struct bio_integrity_payload *bip =
365 container_of(work, struct bio_integrity_payload, bip_work);
366 struct bio *bio = bip->bip_bio;
367 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
369 bio->bi_error = bio_integrity_process(bio, bi->profile->verify_fn);
371 /* Restore original bio completion handler */
372 bio->bi_end_io = bip->bip_end_io;
377 * bio_integrity_endio - Integrity I/O completion function
378 * @bio: Protected bio
379 * @error: Pointer to errno
381 * Description: Completion for integrity I/O
383 * Normally I/O completion is done in interrupt context. However,
384 * verifying I/O integrity is a time-consuming task which must be run
385 * in process context. This function postpones completion
388 void bio_integrity_endio(struct bio *bio)
390 struct bio_integrity_payload *bip = bio_integrity(bio);
392 BUG_ON(bip->bip_bio != bio);
394 /* In case of an I/O error there is no point in verifying the
395 * integrity metadata. Restore original bio end_io handler
399 bio->bi_end_io = bip->bip_end_io;
405 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
406 queue_work(kintegrityd_wq, &bip->bip_work);
408 EXPORT_SYMBOL(bio_integrity_endio);
411 * bio_integrity_advance - Advance integrity vector
412 * @bio: bio whose integrity vector to update
413 * @bytes_done: number of data bytes that have been completed
415 * Description: This function calculates how many integrity bytes the
416 * number of completed data bytes correspond to and advances the
417 * integrity vector accordingly.
419 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
421 struct bio_integrity_payload *bip = bio_integrity(bio);
422 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
423 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
425 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
427 EXPORT_SYMBOL(bio_integrity_advance);
430 * bio_integrity_trim - Trim integrity vector
431 * @bio: bio whose integrity vector to update
432 * @offset: offset to first data sector
433 * @sectors: number of data sectors
435 * Description: Used to trim the integrity vector in a cloned bio.
436 * The ivec will be advanced corresponding to 'offset' data sectors
437 * and the length will be truncated corresponding to 'len' data
440 void bio_integrity_trim(struct bio *bio, unsigned int offset,
441 unsigned int sectors)
443 struct bio_integrity_payload *bip = bio_integrity(bio);
444 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
446 bio_integrity_advance(bio, offset << 9);
447 bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
449 EXPORT_SYMBOL(bio_integrity_trim);
452 * bio_integrity_clone - Callback for cloning bios with integrity metadata
454 * @bio_src: Original bio
455 * @gfp_mask: Memory allocation mask
457 * Description: Called to allocate a bip when cloning a bio
459 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
462 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
463 struct bio_integrity_payload *bip;
465 BUG_ON(bip_src == NULL);
467 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
471 memcpy(bip->bip_vec, bip_src->bip_vec,
472 bip_src->bip_vcnt * sizeof(struct bio_vec));
474 bip->bip_vcnt = bip_src->bip_vcnt;
475 bip->bip_iter = bip_src->bip_iter;
479 EXPORT_SYMBOL(bio_integrity_clone);
481 int bioset_integrity_create(struct bio_set *bs, int pool_size)
483 if (bs->bio_integrity_pool)
486 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
487 if (!bs->bio_integrity_pool)
490 bs->bvec_integrity_pool = biovec_create_pool(pool_size);
491 if (!bs->bvec_integrity_pool) {
492 mempool_destroy(bs->bio_integrity_pool);
498 EXPORT_SYMBOL(bioset_integrity_create);
500 void bioset_integrity_free(struct bio_set *bs)
502 if (bs->bio_integrity_pool)
503 mempool_destroy(bs->bio_integrity_pool);
505 if (bs->bvec_integrity_pool)
506 mempool_destroy(bs->bvec_integrity_pool);
508 EXPORT_SYMBOL(bioset_integrity_free);
510 void __init bio_integrity_init(void)
513 * kintegrityd won't block much but may burn a lot of CPU cycles.
514 * Make it highpri CPU intensive wq with max concurrency of 1.
516 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
517 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
519 panic("Failed to create kintegrityd\n");
521 bip_slab = kmem_cache_create("bio_integrity_payload",
522 sizeof(struct bio_integrity_payload) +
523 sizeof(struct bio_vec) * BIP_INLINE_VECS,
524 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);