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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 | #include "blk.h" | |
30 | ||
31 | #define BIP_INLINE_VECS 4 | |
32 | ||
33 | static struct kmem_cache *bip_slab; | |
34 | static struct workqueue_struct *kintegrityd_wq; | |
35 | ||
36 | void blk_flush_integrity(void) | |
37 | { | |
38 | flush_workqueue(kintegrityd_wq); | |
39 | } | |
40 | ||
41 | /** | |
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 | |
46 | * | |
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. | |
50 | */ | |
51 | struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, | |
52 | gfp_t gfp_mask, | |
53 | unsigned int nr_vecs) | |
54 | { | |
55 | struct bio_integrity_payload *bip; | |
56 | struct bio_set *bs = bio->bi_pool; | |
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 ERR_PTR(-ENOMEM); | |
70 | ||
71 | memset(bip, 0, sizeof(*bip)); | |
72 | ||
73 | if (nr_vecs > inline_vecs) { | |
74 | unsigned long idx = 0; | |
75 | ||
76 | bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx, | |
77 | bs->bvec_integrity_pool); | |
78 | if (!bip->bip_vec) | |
79 | goto err; | |
80 | bip->bip_max_vcnt = bvec_nr_vecs(idx); | |
81 | bip->bip_slab = idx; | |
82 | } else { | |
83 | bip->bip_vec = bip->bip_inline_vecs; | |
84 | bip->bip_max_vcnt = inline_vecs; | |
85 | } | |
86 | ||
87 | bip->bip_bio = bio; | |
88 | bio->bi_integrity = bip; | |
89 | bio->bi_opf |= REQ_INTEGRITY; | |
90 | ||
91 | return bip; | |
92 | err: | |
93 | mempool_free(bip, bs->bio_integrity_pool); | |
94 | return ERR_PTR(-ENOMEM); | |
95 | } | |
96 | EXPORT_SYMBOL(bio_integrity_alloc); | |
97 | ||
98 | /** | |
99 | * bio_integrity_free - Free bio integrity payload | |
100 | * @bio: bio containing bip to be freed | |
101 | * | |
102 | * Description: Used to free the integrity portion of a bio. Usually | |
103 | * called from bio_free(). | |
104 | */ | |
105 | void bio_integrity_free(struct bio *bio) | |
106 | { | |
107 | struct bio_integrity_payload *bip = bio_integrity(bio); | |
108 | struct bio_set *bs = bio->bi_pool; | |
109 | ||
110 | if (bip->bip_flags & BIP_BLOCK_INTEGRITY) | |
111 | kfree(page_address(bip->bip_vec->bv_page) + | |
112 | bip->bip_vec->bv_offset); | |
113 | ||
114 | if (bs && bs->bio_integrity_pool) { | |
115 | bvec_free(bs->bvec_integrity_pool, bip->bip_vec, 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 | */ | |
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 | */ | |
171 | bool bio_integrity_enabled(struct bio *bio) | |
172 | { | |
173 | struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); | |
174 | ||
175 | if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE) | |
176 | return false; | |
177 | ||
178 | /* Already protected? */ | |
179 | if (bio_integrity(bio)) | |
180 | return false; | |
181 | ||
182 | if (bi == NULL) | |
183 | return false; | |
184 | ||
185 | if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL && | |
186 | (bi->flags & BLK_INTEGRITY_VERIFY)) | |
187 | return true; | |
188 | ||
189 | if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL && | |
190 | (bi->flags & BLK_INTEGRITY_GENERATE)) | |
191 | return true; | |
192 | ||
193 | return false; | |
194 | } | |
195 | EXPORT_SYMBOL(bio_integrity_enabled); | |
196 | ||
197 | /** | |
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 | |
201 | * | |
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. | |
206 | */ | |
207 | static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi, | |
208 | unsigned int sectors) | |
209 | { | |
210 | return sectors >> (bi->interval_exp - 9); | |
211 | } | |
212 | ||
213 | static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi, | |
214 | unsigned int sectors) | |
215 | { | |
216 | return bio_integrity_intervals(bi, sectors) * bi->tuple_size; | |
217 | } | |
218 | ||
219 | /** | |
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 | |
223 | */ | |
224 | static int bio_integrity_process(struct bio *bio, | |
225 | integrity_processing_fn *proc_fn) | |
226 | { | |
227 | struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); | |
228 | struct blk_integrity_iter iter; | |
229 | struct bvec_iter bviter; | |
230 | struct bio_vec bv; | |
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; | |
235 | ||
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; | |
240 | ||
241 | bio_for_each_segment(bv, bio, bviter) { | |
242 | void *kaddr = kmap_atomic(bv.bv_page); | |
243 | ||
244 | iter.data_buf = kaddr + bv.bv_offset; | |
245 | iter.data_size = bv.bv_len; | |
246 | ||
247 | ret = proc_fn(&iter); | |
248 | if (ret) { | |
249 | kunmap_atomic(kaddr); | |
250 | return ret; | |
251 | } | |
252 | ||
253 | kunmap_atomic(kaddr); | |
254 | } | |
255 | return ret; | |
256 | } | |
257 | ||
258 | /** | |
259 | * bio_integrity_prep - Prepare bio for integrity I/O | |
260 | * @bio: bio to prepare | |
261 | * | |
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. | |
268 | */ | |
269 | int bio_integrity_prep(struct bio *bio) | |
270 | { | |
271 | struct bio_integrity_payload *bip; | |
272 | struct blk_integrity *bi; | |
273 | struct request_queue *q; | |
274 | void *buf; | |
275 | unsigned long start, end; | |
276 | unsigned int len, nr_pages; | |
277 | unsigned int bytes, offset, i; | |
278 | unsigned int intervals; | |
279 | ||
280 | bi = bdev_get_integrity(bio->bi_bdev); | |
281 | q = bdev_get_queue(bio->bi_bdev); | |
282 | BUG_ON(bi == NULL); | |
283 | BUG_ON(bio_integrity(bio)); | |
284 | ||
285 | intervals = bio_integrity_intervals(bi, bio_sectors(bio)); | |
286 | ||
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"); | |
292 | return -ENOMEM; | |
293 | } | |
294 | ||
295 | end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
296 | start = ((unsigned long) buf) >> PAGE_SHIFT; | |
297 | nr_pages = end - start; | |
298 | ||
299 | /* Allocate bio integrity payload and integrity vectors */ | |
300 | bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages); | |
301 | if (IS_ERR(bip)) { | |
302 | printk(KERN_ERR "could not allocate data integrity bioset\n"); | |
303 | kfree(buf); | |
304 | return PTR_ERR(bip); | |
305 | } | |
306 | ||
307 | bip->bip_flags |= BIP_BLOCK_INTEGRITY; | |
308 | bip->bip_iter.bi_size = len; | |
309 | bip_set_seed(bip, bio->bi_iter.bi_sector); | |
310 | ||
311 | if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM) | |
312 | bip->bip_flags |= BIP_IP_CHECKSUM; | |
313 | ||
314 | /* Map it */ | |
315 | offset = offset_in_page(buf); | |
316 | for (i = 0 ; i < nr_pages ; i++) { | |
317 | int ret; | |
318 | bytes = PAGE_SIZE - offset; | |
319 | ||
320 | if (len <= 0) | |
321 | break; | |
322 | ||
323 | if (bytes > len) | |
324 | bytes = len; | |
325 | ||
326 | ret = bio_integrity_add_page(bio, virt_to_page(buf), | |
327 | bytes, offset); | |
328 | ||
329 | if (ret == 0) | |
330 | return 0; | |
331 | ||
332 | if (ret < bytes) | |
333 | break; | |
334 | ||
335 | buf += bytes; | |
336 | len -= bytes; | |
337 | offset = 0; | |
338 | } | |
339 | ||
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; | |
344 | } | |
345 | ||
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); | |
349 | ||
350 | return 0; | |
351 | } | |
352 | EXPORT_SYMBOL(bio_integrity_prep); | |
353 | ||
354 | /** | |
355 | * bio_integrity_verify_fn - Integrity I/O completion worker | |
356 | * @work: Work struct stored in bio to be verified | |
357 | * | |
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. | |
361 | */ | |
362 | static void bio_integrity_verify_fn(struct work_struct *work) | |
363 | { | |
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); | |
368 | ||
369 | bio->bi_error = bio_integrity_process(bio, bi->profile->verify_fn); | |
370 | ||
371 | /* Restore original bio completion handler */ | |
372 | bio->bi_end_io = bip->bip_end_io; | |
373 | bio_endio(bio); | |
374 | } | |
375 | ||
376 | /** | |
377 | * bio_integrity_endio - Integrity I/O completion function | |
378 | * @bio: Protected bio | |
379 | * @error: Pointer to errno | |
380 | * | |
381 | * Description: Completion for integrity I/O | |
382 | * | |
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 | |
386 | * accordingly. | |
387 | */ | |
388 | void bio_integrity_endio(struct bio *bio) | |
389 | { | |
390 | struct bio_integrity_payload *bip = bio_integrity(bio); | |
391 | ||
392 | BUG_ON(bip->bip_bio != bio); | |
393 | ||
394 | /* In case of an I/O error there is no point in verifying the | |
395 | * integrity metadata. Restore original bio end_io handler | |
396 | * and run it. | |
397 | */ | |
398 | if (bio->bi_error) { | |
399 | bio->bi_end_io = bip->bip_end_io; | |
400 | bio_endio(bio); | |
401 | ||
402 | return; | |
403 | } | |
404 | ||
405 | INIT_WORK(&bip->bip_work, bio_integrity_verify_fn); | |
406 | queue_work(kintegrityd_wq, &bip->bip_work); | |
407 | } | |
408 | EXPORT_SYMBOL(bio_integrity_endio); | |
409 | ||
410 | /** | |
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 | |
414 | * | |
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. | |
418 | */ | |
419 | void bio_integrity_advance(struct bio *bio, unsigned int bytes_done) | |
420 | { | |
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); | |
424 | ||
425 | bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes); | |
426 | } | |
427 | EXPORT_SYMBOL(bio_integrity_advance); | |
428 | ||
429 | /** | |
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 | |
434 | * | |
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 | |
438 | * sectors. | |
439 | */ | |
440 | void bio_integrity_trim(struct bio *bio, unsigned int offset, | |
441 | unsigned int sectors) | |
442 | { | |
443 | struct bio_integrity_payload *bip = bio_integrity(bio); | |
444 | struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); | |
445 | ||
446 | bio_integrity_advance(bio, offset << 9); | |
447 | bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors); | |
448 | } | |
449 | EXPORT_SYMBOL(bio_integrity_trim); | |
450 | ||
451 | /** | |
452 | * bio_integrity_clone - Callback for cloning bios with integrity metadata | |
453 | * @bio: New bio | |
454 | * @bio_src: Original bio | |
455 | * @gfp_mask: Memory allocation mask | |
456 | * | |
457 | * Description: Called to allocate a bip when cloning a bio | |
458 | */ | |
459 | int bio_integrity_clone(struct bio *bio, struct bio *bio_src, | |
460 | gfp_t gfp_mask) | |
461 | { | |
462 | struct bio_integrity_payload *bip_src = bio_integrity(bio_src); | |
463 | struct bio_integrity_payload *bip; | |
464 | ||
465 | BUG_ON(bip_src == NULL); | |
466 | ||
467 | bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt); | |
468 | if (IS_ERR(bip)) | |
469 | return PTR_ERR(bip); | |
470 | ||
471 | memcpy(bip->bip_vec, bip_src->bip_vec, | |
472 | bip_src->bip_vcnt * sizeof(struct bio_vec)); | |
473 | ||
474 | bip->bip_vcnt = bip_src->bip_vcnt; | |
475 | bip->bip_iter = bip_src->bip_iter; | |
476 | ||
477 | return 0; | |
478 | } | |
479 | EXPORT_SYMBOL(bio_integrity_clone); | |
480 | ||
481 | int bioset_integrity_create(struct bio_set *bs, int pool_size) | |
482 | { | |
483 | if (bs->bio_integrity_pool) | |
484 | return 0; | |
485 | ||
486 | bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab); | |
487 | if (!bs->bio_integrity_pool) | |
488 | return -1; | |
489 | ||
490 | bs->bvec_integrity_pool = biovec_create_pool(pool_size); | |
491 | if (!bs->bvec_integrity_pool) { | |
492 | mempool_destroy(bs->bio_integrity_pool); | |
493 | return -1; | |
494 | } | |
495 | ||
496 | return 0; | |
497 | } | |
498 | EXPORT_SYMBOL(bioset_integrity_create); | |
499 | ||
500 | void bioset_integrity_free(struct bio_set *bs) | |
501 | { | |
502 | if (bs->bio_integrity_pool) | |
503 | mempool_destroy(bs->bio_integrity_pool); | |
504 | ||
505 | if (bs->bvec_integrity_pool) | |
506 | mempool_destroy(bs->bvec_integrity_pool); | |
507 | } | |
508 | EXPORT_SYMBOL(bioset_integrity_free); | |
509 | ||
510 | void __init bio_integrity_init(void) | |
511 | { | |
512 | /* | |
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. | |
515 | */ | |
516 | kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM | | |
517 | WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1); | |
518 | if (!kintegrityd_wq) | |
519 | panic("Failed to create kintegrityd\n"); | |
520 | ||
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); | |
525 | } |