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
35 /**
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
40 *
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.
44 */
bio_integrity_alloc(struct bio * bio,gfp_t gfp_mask,unsigned int nr_vecs)45 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
46 gfp_t gfp_mask,
47 unsigned int nr_vecs)
48 {
49 struct bio_integrity_payload *bip;
50 struct bio_set *bs = bio->bi_pool;
51 unsigned long idx = BIO_POOL_NONE;
52 unsigned inline_vecs;
53
54 if (!bs) {
55 bip = kmalloc(sizeof(struct bio_integrity_payload) +
56 sizeof(struct bio_vec) * nr_vecs, gfp_mask);
57 inline_vecs = nr_vecs;
58 } else {
59 bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
60 inline_vecs = BIP_INLINE_VECS;
61 }
62
63 if (unlikely(!bip))
64 return NULL;
65
66 memset(bip, 0, sizeof(*bip));
67
68 if (nr_vecs > inline_vecs) {
69 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
70 bs->bvec_integrity_pool);
71 if (!bip->bip_vec)
72 goto err;
73 bip->bip_max_vcnt = bvec_nr_vecs(idx);
74 } else {
75 bip->bip_vec = bip->bip_inline_vecs;
76 bip->bip_max_vcnt = inline_vecs;
77 }
78
79 bip->bip_slab = idx;
80 bip->bip_bio = bio;
81 bio->bi_integrity = bip;
82 bio->bi_rw |= REQ_INTEGRITY;
83
84 return bip;
85 err:
86 mempool_free(bip, bs->bio_integrity_pool);
87 return NULL;
88 }
89 EXPORT_SYMBOL(bio_integrity_alloc);
90
91 /**
92 * bio_integrity_free - Free bio integrity payload
93 * @bio: bio containing bip to be freed
94 *
95 * Description: Used to free the integrity portion of a bio. Usually
96 * called from bio_free().
97 */
bio_integrity_free(struct bio * bio)98 void bio_integrity_free(struct bio *bio)
99 {
100 struct bio_integrity_payload *bip = bio_integrity(bio);
101 struct bio_set *bs = bio->bi_pool;
102
103 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
104 kfree(page_address(bip->bip_vec->bv_page) +
105 bip->bip_vec->bv_offset);
106
107 if (bs) {
108 if (bip->bip_slab != BIO_POOL_NONE)
109 bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
110 bip->bip_slab);
111
112 mempool_free(bip, bs->bio_integrity_pool);
113 } else {
114 kfree(bip);
115 }
116
117 bio->bi_integrity = NULL;
118 }
119 EXPORT_SYMBOL(bio_integrity_free);
120
121 /**
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
127 *
128 * Description: Attach a page containing integrity metadata to bio.
129 */
bio_integrity_add_page(struct bio * bio,struct page * page,unsigned int len,unsigned int offset)130 int bio_integrity_add_page(struct bio *bio, struct page *page,
131 unsigned int len, unsigned int offset)
132 {
133 struct bio_integrity_payload *bip = bio_integrity(bio);
134 struct bio_vec *iv;
135
136 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
137 printk(KERN_ERR "%s: bip_vec full\n", __func__);
138 return 0;
139 }
140
141 iv = bip->bip_vec + bip->bip_vcnt;
142
143 iv->bv_page = page;
144 iv->bv_len = len;
145 iv->bv_offset = offset;
146 bip->bip_vcnt++;
147
148 return len;
149 }
150 EXPORT_SYMBOL(bio_integrity_add_page);
151
152 /**
153 * bio_integrity_enabled - Check whether integrity can be passed
154 * @bio: bio to check
155 *
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.
160 */
bio_integrity_enabled(struct bio * bio)161 bool bio_integrity_enabled(struct bio *bio)
162 {
163 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
164
165 if (!bio_is_rw(bio))
166 return false;
167
168 /* Already protected? */
169 if (bio_integrity(bio))
170 return false;
171
172 if (bi == NULL)
173 return false;
174
175 if (bio_data_dir(bio) == READ && bi->verify_fn != NULL &&
176 (bi->flags & BLK_INTEGRITY_VERIFY))
177 return true;
178
179 if (bio_data_dir(bio) == WRITE && bi->generate_fn != NULL &&
180 (bi->flags & BLK_INTEGRITY_GENERATE))
181 return true;
182
183 return false;
184 }
185 EXPORT_SYMBOL(bio_integrity_enabled);
186
187 /**
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
191 *
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.
196 */
bio_integrity_intervals(struct blk_integrity * bi,unsigned int sectors)197 static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
198 unsigned int sectors)
199 {
200 return sectors >> (ilog2(bi->interval) - 9);
201 }
202
bio_integrity_bytes(struct blk_integrity * bi,unsigned int sectors)203 static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
204 unsigned int sectors)
205 {
206 return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
207 }
208
209 /**
210 * bio_integrity_process - Process integrity metadata for a bio
211 * @bio: bio to generate/verify integrity metadata for
212 * @proc_fn: Pointer to the relevant processing function
213 */
bio_integrity_process(struct bio * bio,integrity_processing_fn * proc_fn)214 static int bio_integrity_process(struct bio *bio,
215 integrity_processing_fn *proc_fn)
216 {
217 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
218 struct blk_integrity_iter iter;
219 struct bvec_iter bviter;
220 struct bio_vec bv;
221 struct bio_integrity_payload *bip = bio_integrity(bio);
222 unsigned int ret = 0;
223 void *prot_buf = page_address(bip->bip_vec->bv_page) +
224 bip->bip_vec->bv_offset;
225
226 iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
227 iter.interval = bi->interval;
228 iter.seed = bip_get_seed(bip);
229 iter.prot_buf = prot_buf;
230
231 bio_for_each_segment(bv, bio, bviter) {
232 void *kaddr = kmap_atomic(bv.bv_page);
233
234 iter.data_buf = kaddr + bv.bv_offset;
235 iter.data_size = bv.bv_len;
236
237 ret = proc_fn(&iter);
238 if (ret) {
239 kunmap_atomic(kaddr);
240 return ret;
241 }
242
243 kunmap_atomic(kaddr);
244 }
245 return ret;
246 }
247
248 /**
249 * bio_integrity_prep - Prepare bio for integrity I/O
250 * @bio: bio to prepare
251 *
252 * Description: Allocates a buffer for integrity metadata, maps the
253 * pages and attaches them to a bio. The bio must have data
254 * direction, target device and start sector set priot to calling. In
255 * the WRITE case, integrity metadata will be generated using the
256 * block device's integrity function. In the READ case, the buffer
257 * will be prepared for DMA and a suitable end_io handler set up.
258 */
bio_integrity_prep(struct bio * bio)259 int bio_integrity_prep(struct bio *bio)
260 {
261 struct bio_integrity_payload *bip;
262 struct blk_integrity *bi;
263 struct request_queue *q;
264 void *buf;
265 unsigned long start, end;
266 unsigned int len, nr_pages;
267 unsigned int bytes, offset, i;
268 unsigned int intervals;
269
270 bi = bdev_get_integrity(bio->bi_bdev);
271 q = bdev_get_queue(bio->bi_bdev);
272 BUG_ON(bi == NULL);
273 BUG_ON(bio_integrity(bio));
274
275 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
276
277 /* Allocate kernel buffer for protection data */
278 len = intervals * bi->tuple_size;
279 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
280 if (unlikely(buf == NULL)) {
281 printk(KERN_ERR "could not allocate integrity buffer\n");
282 return -ENOMEM;
283 }
284
285 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
286 start = ((unsigned long) buf) >> PAGE_SHIFT;
287 nr_pages = end - start;
288
289 /* Allocate bio integrity payload and integrity vectors */
290 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
291 if (unlikely(bip == NULL)) {
292 printk(KERN_ERR "could not allocate data integrity bioset\n");
293 kfree(buf);
294 return -EIO;
295 }
296
297 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
298 bip->bip_iter.bi_size = len;
299 bip_set_seed(bip, bio->bi_iter.bi_sector);
300
301 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
302 bip->bip_flags |= BIP_IP_CHECKSUM;
303
304 /* Map it */
305 offset = offset_in_page(buf);
306 for (i = 0 ; i < nr_pages ; i++) {
307 int ret;
308 bytes = PAGE_SIZE - offset;
309
310 if (len <= 0)
311 break;
312
313 if (bytes > len)
314 bytes = len;
315
316 ret = bio_integrity_add_page(bio, virt_to_page(buf),
317 bytes, offset);
318
319 if (ret == 0)
320 return 0;
321
322 if (ret < bytes)
323 break;
324
325 buf += bytes;
326 len -= bytes;
327 offset = 0;
328 }
329
330 /* Install custom I/O completion handler if read verify is enabled */
331 if (bio_data_dir(bio) == READ) {
332 bip->bip_end_io = bio->bi_end_io;
333 bio->bi_end_io = bio_integrity_endio;
334 }
335
336 /* Auto-generate integrity metadata if this is a write */
337 if (bio_data_dir(bio) == WRITE)
338 bio_integrity_process(bio, bi->generate_fn);
339
340 return 0;
341 }
342 EXPORT_SYMBOL(bio_integrity_prep);
343
344 /**
345 * bio_integrity_verify_fn - Integrity I/O completion worker
346 * @work: Work struct stored in bio to be verified
347 *
348 * Description: This workqueue function is called to complete a READ
349 * request. The function verifies the transferred integrity metadata
350 * and then calls the original bio end_io function.
351 */
bio_integrity_verify_fn(struct work_struct * work)352 static void bio_integrity_verify_fn(struct work_struct *work)
353 {
354 struct bio_integrity_payload *bip =
355 container_of(work, struct bio_integrity_payload, bip_work);
356 struct bio *bio = bip->bip_bio;
357 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
358 int error;
359
360 error = bio_integrity_process(bio, bi->verify_fn);
361
362 /* Restore original bio completion handler */
363 bio->bi_end_io = bip->bip_end_io;
364 bio_endio_nodec(bio, error);
365 }
366
367 /**
368 * bio_integrity_endio - Integrity I/O completion function
369 * @bio: Protected bio
370 * @error: Pointer to errno
371 *
372 * Description: Completion for integrity I/O
373 *
374 * Normally I/O completion is done in interrupt context. However,
375 * verifying I/O integrity is a time-consuming task which must be run
376 * in process context. This function postpones completion
377 * accordingly.
378 */
bio_integrity_endio(struct bio * bio,int error)379 void bio_integrity_endio(struct bio *bio, int error)
380 {
381 struct bio_integrity_payload *bip = bio_integrity(bio);
382
383 BUG_ON(bip->bip_bio != bio);
384
385 /* In case of an I/O error there is no point in verifying the
386 * integrity metadata. Restore original bio end_io handler
387 * and run it.
388 */
389 if (error) {
390 bio->bi_end_io = bip->bip_end_io;
391 bio_endio_nodec(bio, error);
392
393 return;
394 }
395
396 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
397 queue_work(kintegrityd_wq, &bip->bip_work);
398 }
399 EXPORT_SYMBOL(bio_integrity_endio);
400
401 /**
402 * bio_integrity_advance - Advance integrity vector
403 * @bio: bio whose integrity vector to update
404 * @bytes_done: number of data bytes that have been completed
405 *
406 * Description: This function calculates how many integrity bytes the
407 * number of completed data bytes correspond to and advances the
408 * integrity vector accordingly.
409 */
bio_integrity_advance(struct bio * bio,unsigned int bytes_done)410 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
411 {
412 struct bio_integrity_payload *bip = bio_integrity(bio);
413 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
414 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
415
416 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
417 }
418 EXPORT_SYMBOL(bio_integrity_advance);
419
420 /**
421 * bio_integrity_trim - Trim integrity vector
422 * @bio: bio whose integrity vector to update
423 * @offset: offset to first data sector
424 * @sectors: number of data sectors
425 *
426 * Description: Used to trim the integrity vector in a cloned bio.
427 * The ivec will be advanced corresponding to 'offset' data sectors
428 * and the length will be truncated corresponding to 'len' data
429 * sectors.
430 */
bio_integrity_trim(struct bio * bio,unsigned int offset,unsigned int sectors)431 void bio_integrity_trim(struct bio *bio, unsigned int offset,
432 unsigned int sectors)
433 {
434 struct bio_integrity_payload *bip = bio_integrity(bio);
435 struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
436
437 bio_integrity_advance(bio, offset << 9);
438 bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
439 }
440 EXPORT_SYMBOL(bio_integrity_trim);
441
442 /**
443 * bio_integrity_clone - Callback for cloning bios with integrity metadata
444 * @bio: New bio
445 * @bio_src: Original bio
446 * @gfp_mask: Memory allocation mask
447 *
448 * Description: Called to allocate a bip when cloning a bio
449 */
bio_integrity_clone(struct bio * bio,struct bio * bio_src,gfp_t gfp_mask)450 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
451 gfp_t gfp_mask)
452 {
453 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
454 struct bio_integrity_payload *bip;
455
456 BUG_ON(bip_src == NULL);
457
458 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
459
460 if (bip == NULL)
461 return -EIO;
462
463 memcpy(bip->bip_vec, bip_src->bip_vec,
464 bip_src->bip_vcnt * sizeof(struct bio_vec));
465
466 bip->bip_vcnt = bip_src->bip_vcnt;
467 bip->bip_iter = bip_src->bip_iter;
468
469 return 0;
470 }
471 EXPORT_SYMBOL(bio_integrity_clone);
472
bioset_integrity_create(struct bio_set * bs,int pool_size)473 int bioset_integrity_create(struct bio_set *bs, int pool_size)
474 {
475 if (bs->bio_integrity_pool)
476 return 0;
477
478 bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
479 if (!bs->bio_integrity_pool)
480 return -1;
481
482 bs->bvec_integrity_pool = biovec_create_pool(pool_size);
483 if (!bs->bvec_integrity_pool) {
484 mempool_destroy(bs->bio_integrity_pool);
485 return -1;
486 }
487
488 return 0;
489 }
490 EXPORT_SYMBOL(bioset_integrity_create);
491
bioset_integrity_free(struct bio_set * bs)492 void bioset_integrity_free(struct bio_set *bs)
493 {
494 if (bs->bio_integrity_pool)
495 mempool_destroy(bs->bio_integrity_pool);
496
497 if (bs->bvec_integrity_pool)
498 mempool_destroy(bs->bvec_integrity_pool);
499 }
500 EXPORT_SYMBOL(bioset_integrity_free);
501
bio_integrity_init(void)502 void __init bio_integrity_init(void)
503 {
504 /*
505 * kintegrityd won't block much but may burn a lot of CPU cycles.
506 * Make it highpri CPU intensive wq with max concurrency of 1.
507 */
508 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
509 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
510 if (!kintegrityd_wq)
511 panic("Failed to create kintegrityd\n");
512
513 bip_slab = kmem_cache_create("bio_integrity_payload",
514 sizeof(struct bio_integrity_payload) +
515 sizeof(struct bio_vec) * BIP_INLINE_VECS,
516 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
517 }
518