1 // SPDX-License-Identifier: GPL-2.0
3 * bio-integrity.c - bio data integrity extensions
5 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
6 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
9 #include <linux/blkdev.h>
10 #include <linux/mempool.h>
11 #include <linux/export.h>
12 #include <linux/bio.h>
13 #include <linux/workqueue.h>
14 #include <linux/slab.h>
17 #define BIP_INLINE_VECS 4
19 static struct kmem_cache *bip_slab;
20 static struct workqueue_struct *kintegrityd_wq;
22 void blk_flush_integrity(void)
24 flush_workqueue(kintegrityd_wq);
28 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
29 * @bio: bio to attach integrity metadata to
30 * @gfp_mask: Memory allocation mask
31 * @nr_vecs: Number of integrity metadata scatter-gather elements
33 * Description: This function prepares a bio for attaching integrity
34 * metadata. nr_vecs specifies the maximum number of pages containing
35 * integrity metadata that can be attached.
37 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
41 struct bio_integrity_payload *bip;
42 struct bio_set *bs = bio->bi_pool;
45 if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
46 bip = kmalloc(sizeof(struct bio_integrity_payload) +
47 sizeof(struct bio_vec) * nr_vecs, gfp_mask);
48 inline_vecs = nr_vecs;
50 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
51 inline_vecs = BIP_INLINE_VECS;
55 return ERR_PTR(-ENOMEM);
57 memset(bip, 0, sizeof(*bip));
59 if (nr_vecs > inline_vecs) {
60 unsigned long idx = 0;
62 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
63 &bs->bvec_integrity_pool);
66 bip->bip_max_vcnt = bvec_nr_vecs(idx);
69 bip->bip_vec = bip->bip_inline_vecs;
70 bip->bip_max_vcnt = inline_vecs;
74 bio->bi_integrity = bip;
75 bio->bi_opf |= REQ_INTEGRITY;
79 mempool_free(bip, &bs->bio_integrity_pool);
80 return ERR_PTR(-ENOMEM);
82 EXPORT_SYMBOL(bio_integrity_alloc);
85 * bio_integrity_free - Free bio integrity payload
86 * @bio: bio containing bip to be freed
88 * Description: Used to free the integrity portion of a bio. Usually
89 * called from bio_free().
91 static void bio_integrity_free(struct bio *bio)
93 struct bio_integrity_payload *bip = bio_integrity(bio);
94 struct bio_set *bs = bio->bi_pool;
96 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
97 kfree(page_address(bip->bip_vec->bv_page) +
98 bip->bip_vec->bv_offset);
100 if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
101 bvec_free(&bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab);
103 mempool_free(bip, &bs->bio_integrity_pool);
108 bio->bi_integrity = NULL;
109 bio->bi_opf &= ~REQ_INTEGRITY;
113 * bio_integrity_add_page - Attach integrity metadata
114 * @bio: bio to update
115 * @page: page containing integrity metadata
116 * @len: number of bytes of integrity metadata in page
117 * @offset: start offset within page
119 * Description: Attach a page containing integrity metadata to bio.
121 int bio_integrity_add_page(struct bio *bio, struct page *page,
122 unsigned int len, unsigned int offset)
124 struct bio_integrity_payload *bip = bio_integrity(bio);
127 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
128 printk(KERN_ERR "%s: bip_vec full\n", __func__);
132 iv = bip->bip_vec + bip->bip_vcnt;
135 bvec_gap_to_prev(bio->bi_disk->queue,
136 &bip->bip_vec[bip->bip_vcnt - 1], offset))
141 iv->bv_offset = offset;
146 EXPORT_SYMBOL(bio_integrity_add_page);
149 * bio_integrity_process - Process integrity metadata for a bio
150 * @bio: bio to generate/verify integrity metadata for
151 * @proc_iter: iterator to process
152 * @proc_fn: Pointer to the relevant processing function
154 static blk_status_t bio_integrity_process(struct bio *bio,
155 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
157 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
158 struct blk_integrity_iter iter;
159 struct bvec_iter bviter;
161 struct bio_integrity_payload *bip = bio_integrity(bio);
162 blk_status_t ret = BLK_STS_OK;
163 void *prot_buf = page_address(bip->bip_vec->bv_page) +
164 bip->bip_vec->bv_offset;
166 iter.disk_name = bio->bi_disk->disk_name;
167 iter.interval = 1 << bi->interval_exp;
168 iter.seed = proc_iter->bi_sector;
169 iter.prot_buf = prot_buf;
171 __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
172 void *kaddr = kmap_atomic(bv.bv_page);
174 iter.data_buf = kaddr + bv.bv_offset;
175 iter.data_size = bv.bv_len;
177 ret = proc_fn(&iter);
179 kunmap_atomic(kaddr);
183 kunmap_atomic(kaddr);
189 * bio_integrity_prep - Prepare bio for integrity I/O
190 * @bio: bio to prepare
192 * Description: Checks if the bio already has an integrity payload attached.
193 * If it does, the payload has been generated by another kernel subsystem,
194 * and we just pass it through. Otherwise allocates integrity payload.
195 * The bio must have data direction, target device and start sector set priot
196 * to calling. In the WRITE case, integrity metadata will be generated using
197 * the block device's integrity function. In the READ case, the buffer
198 * will be prepared for DMA and a suitable end_io handler set up.
200 bool bio_integrity_prep(struct bio *bio)
202 struct bio_integrity_payload *bip;
203 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
204 struct request_queue *q = bio->bi_disk->queue;
206 unsigned long start, end;
207 unsigned int len, nr_pages;
208 unsigned int bytes, offset, i;
209 unsigned int intervals;
215 if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
218 if (!bio_sectors(bio))
221 /* Already protected? */
222 if (bio_integrity(bio))
225 if (bio_data_dir(bio) == READ) {
226 if (!bi->profile->verify_fn ||
227 !(bi->flags & BLK_INTEGRITY_VERIFY))
230 if (!bi->profile->generate_fn ||
231 !(bi->flags & BLK_INTEGRITY_GENERATE))
234 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
236 /* Allocate kernel buffer for protection data */
237 len = intervals * bi->tuple_size;
238 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
239 status = BLK_STS_RESOURCE;
240 if (unlikely(buf == NULL)) {
241 printk(KERN_ERR "could not allocate integrity buffer\n");
245 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
246 start = ((unsigned long) buf) >> PAGE_SHIFT;
247 nr_pages = end - start;
249 /* Allocate bio integrity payload and integrity vectors */
250 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
252 printk(KERN_ERR "could not allocate data integrity bioset\n");
254 status = BLK_STS_RESOURCE;
258 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
259 bip->bip_iter.bi_size = len;
260 bip_set_seed(bip, bio->bi_iter.bi_sector);
262 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
263 bip->bip_flags |= BIP_IP_CHECKSUM;
266 offset = offset_in_page(buf);
267 for (i = 0 ; i < nr_pages ; i++) {
269 bytes = PAGE_SIZE - offset;
277 ret = bio_integrity_add_page(bio, virt_to_page(buf),
291 /* Auto-generate integrity metadata if this is a write */
292 if (bio_data_dir(bio) == WRITE) {
293 bio_integrity_process(bio, &bio->bi_iter,
294 bi->profile->generate_fn);
296 bip->bio_iter = bio->bi_iter;
301 bio->bi_status = status;
306 EXPORT_SYMBOL(bio_integrity_prep);
309 * bio_integrity_verify_fn - Integrity I/O completion worker
310 * @work: Work struct stored in bio to be verified
312 * Description: This workqueue function is called to complete a READ
313 * request. The function verifies the transferred integrity metadata
314 * and then calls the original bio end_io function.
316 static void bio_integrity_verify_fn(struct work_struct *work)
318 struct bio_integrity_payload *bip =
319 container_of(work, struct bio_integrity_payload, bip_work);
320 struct bio *bio = bip->bip_bio;
321 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
324 * At the moment verify is called bio's iterator was advanced
325 * during split and completion, we need to rewind iterator to
326 * it's original position.
328 bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
329 bi->profile->verify_fn);
330 bio_integrity_free(bio);
335 * __bio_integrity_endio - Integrity I/O completion function
336 * @bio: Protected bio
338 * Description: Completion for integrity I/O
340 * Normally I/O completion is done in interrupt context. However,
341 * verifying I/O integrity is a time-consuming task which must be run
342 * in process context. This function postpones completion
345 bool __bio_integrity_endio(struct bio *bio)
347 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
348 struct bio_integrity_payload *bip = bio_integrity(bio);
350 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
351 (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
352 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
353 queue_work(kintegrityd_wq, &bip->bip_work);
357 bio_integrity_free(bio);
362 * bio_integrity_advance - Advance integrity vector
363 * @bio: bio whose integrity vector to update
364 * @bytes_done: number of data bytes that have been completed
366 * Description: This function calculates how many integrity bytes the
367 * number of completed data bytes correspond to and advances the
368 * integrity vector accordingly.
370 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
372 struct bio_integrity_payload *bip = bio_integrity(bio);
373 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
374 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
376 bip->bip_iter.bi_sector += bytes_done >> 9;
377 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
381 * bio_integrity_trim - Trim integrity vector
382 * @bio: bio whose integrity vector to update
384 * Description: Used to trim the integrity vector in a cloned bio.
386 void bio_integrity_trim(struct bio *bio)
388 struct bio_integrity_payload *bip = bio_integrity(bio);
389 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
391 bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
393 EXPORT_SYMBOL(bio_integrity_trim);
396 * bio_integrity_clone - Callback for cloning bios with integrity metadata
398 * @bio_src: Original bio
399 * @gfp_mask: Memory allocation mask
401 * Description: Called to allocate a bip when cloning a bio
403 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
406 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
407 struct bio_integrity_payload *bip;
409 BUG_ON(bip_src == NULL);
411 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
415 memcpy(bip->bip_vec, bip_src->bip_vec,
416 bip_src->bip_vcnt * sizeof(struct bio_vec));
418 bip->bip_vcnt = bip_src->bip_vcnt;
419 bip->bip_iter = bip_src->bip_iter;
423 EXPORT_SYMBOL(bio_integrity_clone);
425 int bioset_integrity_create(struct bio_set *bs, int pool_size)
427 if (mempool_initialized(&bs->bio_integrity_pool))
430 if (mempool_init_slab_pool(&bs->bio_integrity_pool,
431 pool_size, bip_slab))
434 if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
435 mempool_exit(&bs->bio_integrity_pool);
441 EXPORT_SYMBOL(bioset_integrity_create);
443 void bioset_integrity_free(struct bio_set *bs)
445 mempool_exit(&bs->bio_integrity_pool);
446 mempool_exit(&bs->bvec_integrity_pool);
449 void __init bio_integrity_init(void)
452 * kintegrityd won't block much but may burn a lot of CPU cycles.
453 * Make it highpri CPU intensive wq with max concurrency of 1.
455 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
456 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
458 panic("Failed to create kintegrityd\n");
460 bip_slab = kmem_cache_create("bio_integrity_payload",
461 sizeof(struct bio_integrity_payload) +
462 sizeof(struct bio_vec) * BIP_INLINE_VECS,
463 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);