1 /*
2 * bio-integrity.c - bio data integrity extensions
3 *
4 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
5 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
6 *
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.
10 *
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.
15 *
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,
19 * USA.
20 *
21 */
22
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>
29
30 #define BIP_INLINE_VECS 4
31
32 static struct kmem_cache *bip_slab;
33 static struct workqueue_struct *kintegrityd_wq;
34
blk_flush_integrity(void)35 void blk_flush_integrity(void)
36 {
37 flush_workqueue(kintegrityd_wq);
38 }
39
40 /**
41 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
42 * @bio: bio to attach integrity metadata to
43 * @gfp_mask: Memory allocation mask
44 * @nr_vecs: Number of integrity metadata scatter-gather elements
45 *
46 * Description: This function prepares a bio for attaching integrity
47 * metadata. nr_vecs specifies the maximum number of pages containing
48 * integrity metadata that can be attached.
49 */
bio_integrity_alloc(struct bio * bio,gfp_t gfp_mask,unsigned int nr_vecs)50 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
51 gfp_t gfp_mask,
52 unsigned int nr_vecs)
53 {
54 struct bio_integrity_payload *bip;
55 struct bio_set *bs = bio->bi_pool;
56 unsigned long idx = BIO_POOL_NONE;
57 unsigned inline_vecs;
58
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;
63 } else {
64 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
65 inline_vecs = BIP_INLINE_VECS;
66 }
67
68 if (unlikely(!bip))
69 return NULL;
70
71 memset(bip, 0, sizeof(*bip));
72
73 if (nr_vecs > inline_vecs) {
74 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
75 bs->bvec_integrity_pool);
76 if (!bip->bip_vec)
77 goto err;
78 bip->bip_max_vcnt = bvec_nr_vecs(idx);
79 } else {
80 bip->bip_vec = bip->bip_inline_vecs;
81 bip->bip_max_vcnt = inline_vecs;
82 }
83
84 bip->bip_slab = idx;
85 bip->bip_bio = bio;
86 bio->bi_integrity = bip;
87 bio->bi_rw |= REQ_INTEGRITY;
88
89 return bip;
90 err:
91 mempool_free(bip, bs->bio_integrity_pool);
92 return NULL;
93 }
94 EXPORT_SYMBOL(bio_integrity_alloc);
95
96 /**
97 * bio_integrity_free - Free bio integrity payload
98 * @bio: bio containing bip to be freed
99 *
100 * Description: Used to free the integrity portion of a bio. Usually
101 * called from bio_free().
102 */
bio_integrity_free(struct bio * bio)103 void bio_integrity_free(struct bio *bio)
104 {
105 struct bio_integrity_payload *bip = bio_integrity(bio);
106 struct bio_set *bs = bio->bi_pool;
107
108 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
109 kfree(page_address(bip->bip_vec->bv_page) +
110 bip->bip_vec->bv_offset);
111
112 if (bs && bs->bio_integrity_pool) {
113 if (bip->bip_slab != BIO_POOL_NONE)
114 bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
115 bip->bip_slab);
116
117 mempool_free(bip, bs->bio_integrity_pool);
118 } else {
119 kfree(bip);
120 }
121
122 bio->bi_integrity = NULL;
123 }
124 EXPORT_SYMBOL(bio_integrity_free);
125
126 /**
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
132 *
133 * Description: Attach a page containing integrity metadata to bio.
134 */
bio_integrity_add_page(struct bio * bio,struct page * page,unsigned int len,unsigned int offset)135 int bio_integrity_add_page(struct bio *bio, struct page *page,
136 unsigned int len, unsigned int offset)
137 {
138 struct bio_integrity_payload *bip = bio_integrity(bio);
139 struct bio_vec *iv;
140
141 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
142 printk(KERN_ERR "%s: bip_vec full\n", __func__);
143 return 0;
144 }
145
146 iv = bip->bip_vec + bip->bip_vcnt;
147
148 if (bip->bip_vcnt &&
149 bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
150 &bip->bip_vec[bip->bip_vcnt - 1], offset))
151 return 0;
152
153 iv->bv_page = page;
154 iv->bv_len = len;
155 iv->bv_offset = offset;
156 bip->bip_vcnt++;
157
158 return len;
159 }
160 EXPORT_SYMBOL(bio_integrity_add_page);
161
162 /**
163 * bio_integrity_enabled - Check whether integrity can be passed
164 * @bio: bio to check
165 *
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.
170 */
bio_integrity_enabled(struct bio * bio)171 bool bio_integrity_enabled(struct bio *bio)
172 {
173 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
174
175 if (!bio_is_rw(bio))
176 return false;
177
178 if (!bio_sectors(bio))
179 return false;
180
181 /* Already protected? */
182 if (bio_integrity(bio))
183 return false;
184
185 if (bi == NULL)
186 return false;
187
188 if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
189 (bi->flags & BLK_INTEGRITY_VERIFY))
190 return true;
191
192 if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
193 (bi->flags & BLK_INTEGRITY_GENERATE))
194 return true;
195
196 return false;
197 }
198 EXPORT_SYMBOL(bio_integrity_enabled);
199
200 /**
201 * bio_integrity_intervals - Return number of integrity intervals for a bio
202 * @bi: blk_integrity profile for device
203 * @sectors: Size of the bio in 512-byte sectors
204 *
205 * Description: The block layer calculates everything in 512 byte
206 * sectors but integrity metadata is done in terms of the data integrity
207 * interval size of the storage device. Convert the block layer sectors
208 * to the appropriate number of integrity intervals.
209 */
bio_integrity_intervals(struct blk_integrity * bi,unsigned int sectors)210 static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
211 unsigned int sectors)
212 {
213 return sectors >> (bi->interval_exp - 9);
214 }
215
bio_integrity_bytes(struct blk_integrity * bi,unsigned int sectors)216 static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
217 unsigned int sectors)
218 {
219 return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
220 }
221
222 /**
223 * bio_integrity_process - Process integrity metadata for a bio
224 * @bio: bio to generate/verify integrity metadata for
225 * @proc_fn: Pointer to the relevant processing function
226 */
bio_integrity_process(struct bio * bio,integrity_processing_fn * proc_fn)227 static int bio_integrity_process(struct bio *bio,
228 integrity_processing_fn *proc_fn)
229 {
230 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
231 struct blk_integrity_iter iter;
232 struct bvec_iter bviter;
233 struct bio_vec bv;
234 struct bio_integrity_payload *bip = bio_integrity(bio);
235 unsigned int ret = 0;
236 void *prot_buf = page_address(bip->bip_vec->bv_page) +
237 bip->bip_vec->bv_offset;
238
239 iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
240 iter.interval = 1 << bi->interval_exp;
241 iter.seed = bip_get_seed(bip);
242 iter.prot_buf = prot_buf;
243
244 bio_for_each_segment(bv, bio, bviter) {
245 void *kaddr = kmap_atomic(bv.bv_page);
246
247 iter.data_buf = kaddr + bv.bv_offset;
248 iter.data_size = bv.bv_len;
249
250 ret = proc_fn(&iter);
251 if (ret) {
252 kunmap_atomic(kaddr);
253 return ret;
254 }
255
256 kunmap_atomic(kaddr);
257 }
258 return ret;
259 }
260
261 /**
262 * bio_integrity_prep - Prepare bio for integrity I/O
263 * @bio: bio to prepare
264 *
265 * Description: Allocates a buffer for integrity metadata, maps the
266 * pages and attaches them to a bio. The bio must have data
267 * direction, target device and start sector set priot to calling. In
268 * the WRITE case, integrity metadata will be generated using the
269 * block device's integrity function. In the READ case, the buffer
270 * will be prepared for DMA and a suitable end_io handler set up.
271 */
bio_integrity_prep(struct bio * bio)272 int bio_integrity_prep(struct bio *bio)
273 {
274 struct bio_integrity_payload *bip;
275 struct blk_integrity *bi;
276 struct request_queue *q;
277 void *buf;
278 unsigned long start, end;
279 unsigned int len, nr_pages;
280 unsigned int bytes, offset, i;
281 unsigned int intervals;
282
283 bi = bdev_get_integrity(bio->bi_bdev);
284 q = bdev_get_queue(bio->bi_bdev);
285 BUG_ON(bi == NULL);
286 BUG_ON(bio_integrity(bio));
287
288 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
289
290 /* Allocate kernel buffer for protection data */
291 len = intervals * bi->tuple_size;
292 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
293 if (unlikely(buf == NULL)) {
294 printk(KERN_ERR "could not allocate integrity buffer\n");
295 return -ENOMEM;
296 }
297
298 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
299 start = ((unsigned long) buf) >> PAGE_SHIFT;
300 nr_pages = end - start;
301
302 /* Allocate bio integrity payload and integrity vectors */
303 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
304 if (unlikely(bip == NULL)) {
305 printk(KERN_ERR "could not allocate data integrity bioset\n");
306 kfree(buf);
307 return -EIO;
308 }
309
310 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
311 bip->bip_iter.bi_size = len;
312 bip_set_seed(bip, bio->bi_iter.bi_sector);
313
314 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
315 bip->bip_flags |= BIP_IP_CHECKSUM;
316
317 /* Map it */
318 offset = offset_in_page(buf);
319 for (i = 0 ; i < nr_pages ; i++) {
320 int ret;
321 bytes = PAGE_SIZE - offset;
322
323 if (len <= 0)
324 break;
325
326 if (bytes > len)
327 bytes = len;
328
329 ret = bio_integrity_add_page(bio, virt_to_page(buf),
330 bytes, offset);
331
332 if (ret == 0)
333 return 0;
334
335 if (ret < bytes)
336 break;
337
338 buf += bytes;
339 len -= bytes;
340 offset = 0;
341 }
342
343 /* Install custom I/O completion handler if read verify is enabled */
344 if (bio_data_dir(bio) == READ) {
345 bip->bip_end_io = bio->bi_end_io;
346 bio->bi_end_io = bio_integrity_endio;
347 }
348
349 /* Auto-generate integrity metadata if this is a write */
350 if (bio_data_dir(bio) == WRITE)
351 bio_integrity_process(bio, bi->profile->generate_fn);
352
353 return 0;
354 }
355 EXPORT_SYMBOL(bio_integrity_prep);
356
357 /**
358 * bio_integrity_verify_fn - Integrity I/O completion worker
359 * @work: Work struct stored in bio to be verified
360 *
361 * Description: This workqueue function is called to complete a READ
362 * request. The function verifies the transferred integrity metadata
363 * and then calls the original bio end_io function.
364 */
bio_integrity_verify_fn(struct work_struct * work)365 static void bio_integrity_verify_fn(struct work_struct *work)
366 {
367 struct bio_integrity_payload *bip =
368 container_of(work, struct bio_integrity_payload, bip_work);
369 struct bio *bio = bip->bip_bio;
370 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
371
372 bio->bi_error = bio_integrity_process(bio, bi->profile->verify_fn);
373
374 /* Restore original bio completion handler */
375 bio->bi_end_io = bip->bip_end_io;
376 bio_endio(bio);
377 }
378
379 /**
380 * bio_integrity_endio - Integrity I/O completion function
381 * @bio: Protected bio
382 * @error: Pointer to errno
383 *
384 * Description: Completion for integrity I/O
385 *
386 * Normally I/O completion is done in interrupt context. However,
387 * verifying I/O integrity is a time-consuming task which must be run
388 * in process context. This function postpones completion
389 * accordingly.
390 */
bio_integrity_endio(struct bio * bio)391 void bio_integrity_endio(struct bio *bio)
392 {
393 struct bio_integrity_payload *bip = bio_integrity(bio);
394
395 BUG_ON(bip->bip_bio != bio);
396
397 /* In case of an I/O error there is no point in verifying the
398 * integrity metadata. Restore original bio end_io handler
399 * and run it.
400 */
401 if (bio->bi_error) {
402 bio->bi_end_io = bip->bip_end_io;
403 bio_endio(bio);
404
405 return;
406 }
407
408 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
409 queue_work(kintegrityd_wq, &bip->bip_work);
410 }
411 EXPORT_SYMBOL(bio_integrity_endio);
412
413 /**
414 * bio_integrity_advance - Advance integrity vector
415 * @bio: bio whose integrity vector to update
416 * @bytes_done: number of data bytes that have been completed
417 *
418 * Description: This function calculates how many integrity bytes the
419 * number of completed data bytes correspond to and advances the
420 * integrity vector accordingly.
421 */
bio_integrity_advance(struct bio * bio,unsigned int bytes_done)422 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
423 {
424 struct bio_integrity_payload *bip = bio_integrity(bio);
425 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
426 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
427
428 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
429 }
430 EXPORT_SYMBOL(bio_integrity_advance);
431
432 /**
433 * bio_integrity_trim - Trim integrity vector
434 * @bio: bio whose integrity vector to update
435 * @offset: offset to first data sector
436 * @sectors: number of data sectors
437 *
438 * Description: Used to trim the integrity vector in a cloned bio.
439 * The ivec will be advanced corresponding to 'offset' data sectors
440 * and the length will be truncated corresponding to 'len' data
441 * sectors.
442 */
bio_integrity_trim(struct bio * bio,unsigned int offset,unsigned int sectors)443 void bio_integrity_trim(struct bio *bio, unsigned int offset,
444 unsigned int sectors)
445 {
446 struct bio_integrity_payload *bip = bio_integrity(bio);
447 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
448
449 bio_integrity_advance(bio, offset << 9);
450 bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
451 }
452 EXPORT_SYMBOL(bio_integrity_trim);
453
454 /**
455 * bio_integrity_clone - Callback for cloning bios with integrity metadata
456 * @bio: New bio
457 * @bio_src: Original bio
458 * @gfp_mask: Memory allocation mask
459 *
460 * Description: Called to allocate a bip when cloning a bio
461 */
bio_integrity_clone(struct bio * bio,struct bio * bio_src,gfp_t gfp_mask)462 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
463 gfp_t gfp_mask)
464 {
465 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
466 struct bio_integrity_payload *bip;
467
468 BUG_ON(bip_src == NULL);
469
470 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
471
472 if (bip == NULL)
473 return -EIO;
474
475 memcpy(bip->bip_vec, bip_src->bip_vec,
476 bip_src->bip_vcnt * sizeof(struct bio_vec));
477
478 bip->bip_vcnt = bip_src->bip_vcnt;
479 bip->bip_iter = bip_src->bip_iter;
480
481 return 0;
482 }
483 EXPORT_SYMBOL(bio_integrity_clone);
484
bioset_integrity_create(struct bio_set * bs,int pool_size)485 int bioset_integrity_create(struct bio_set *bs, int pool_size)
486 {
487 if (bs->bio_integrity_pool)
488 return 0;
489
490 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
491 if (!bs->bio_integrity_pool)
492 return -1;
493
494 bs->bvec_integrity_pool = biovec_create_pool(pool_size);
495 if (!bs->bvec_integrity_pool) {
496 mempool_destroy(bs->bio_integrity_pool);
497 return -1;
498 }
499
500 return 0;
501 }
502 EXPORT_SYMBOL(bioset_integrity_create);
503
bioset_integrity_free(struct bio_set * bs)504 void bioset_integrity_free(struct bio_set *bs)
505 {
506 if (bs->bio_integrity_pool)
507 mempool_destroy(bs->bio_integrity_pool);
508
509 if (bs->bvec_integrity_pool)
510 mempool_destroy(bs->bvec_integrity_pool);
511 }
512 EXPORT_SYMBOL(bioset_integrity_free);
513
bio_integrity_init(void)514 void __init bio_integrity_init(void)
515 {
516 /*
517 * kintegrityd won't block much but may burn a lot of CPU cycles.
518 * Make it highpri CPU intensive wq with max concurrency of 1.
519 */
520 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
521 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
522 if (!kintegrityd_wq)
523 panic("Failed to create kintegrityd\n");
524
525 bip_slab = kmem_cache_create("bio_integrity_payload",
526 sizeof(struct bio_integrity_payload) +
527 sizeof(struct bio_vec) * BIP_INLINE_VECS,
528 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
529 }
530