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
blk_flush_integrity(void)36 void blk_flush_integrity(void)
37 {
38 flush_workqueue(kintegrityd_wq);
39 }
40
__bio_integrity_free(struct bio_set * bs,struct bio_integrity_payload * bip)41 void __bio_integrity_free(struct bio_set *bs, struct bio_integrity_payload *bip)
42 {
43 if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
44 if (bip->bip_vec)
45 bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
46 bip->bip_slab);
47 mempool_free(bip, &bs->bio_integrity_pool);
48 } else {
49 kfree(bip);
50 }
51 }
52
53 /**
54 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
55 * @bio: bio to attach integrity metadata to
56 * @gfp_mask: Memory allocation mask
57 * @nr_vecs: Number of integrity metadata scatter-gather elements
58 *
59 * Description: This function prepares a bio for attaching integrity
60 * metadata. nr_vecs specifies the maximum number of pages containing
61 * integrity metadata that can be attached.
62 */
bio_integrity_alloc(struct bio * bio,gfp_t gfp_mask,unsigned int nr_vecs)63 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
64 gfp_t gfp_mask,
65 unsigned int nr_vecs)
66 {
67 struct bio_integrity_payload *bip;
68 struct bio_set *bs = bio->bi_pool;
69 unsigned inline_vecs;
70
71 if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
72 bip = kmalloc(sizeof(struct bio_integrity_payload) +
73 sizeof(struct bio_vec) * nr_vecs, gfp_mask);
74 inline_vecs = nr_vecs;
75 } else {
76 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
77 inline_vecs = BIP_INLINE_VECS;
78 }
79
80 if (unlikely(!bip))
81 return ERR_PTR(-ENOMEM);
82
83 memset(bip, 0, sizeof(*bip));
84
85 if (nr_vecs > inline_vecs) {
86 unsigned long idx = 0;
87
88 bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
89 &bs->bvec_integrity_pool);
90 if (!bip->bip_vec)
91 goto err;
92 bip->bip_max_vcnt = bvec_nr_vecs(idx);
93 bip->bip_slab = idx;
94 } else {
95 bip->bip_vec = bip->bip_inline_vecs;
96 bip->bip_max_vcnt = inline_vecs;
97 }
98
99 bip->bip_bio = bio;
100 bio->bi_integrity = bip;
101 bio->bi_opf |= REQ_INTEGRITY;
102
103 return bip;
104 err:
105 __bio_integrity_free(bs, bip);
106 return ERR_PTR(-ENOMEM);
107 }
108 EXPORT_SYMBOL(bio_integrity_alloc);
109
110 /**
111 * bio_integrity_free - Free bio integrity payload
112 * @bio: bio containing bip to be freed
113 *
114 * Description: Used to free the integrity portion of a bio. Usually
115 * called from bio_free().
116 */
bio_integrity_free(struct bio * bio)117 static void bio_integrity_free(struct bio *bio)
118 {
119 struct bio_integrity_payload *bip = bio_integrity(bio);
120 struct bio_set *bs = bio->bi_pool;
121
122 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
123 kfree(page_address(bip->bip_vec->bv_page) +
124 bip->bip_vec->bv_offset);
125
126 __bio_integrity_free(bs, bip);
127 bio->bi_integrity = NULL;
128 bio->bi_opf &= ~REQ_INTEGRITY;
129 }
130
131 /**
132 * bio_integrity_add_page - Attach integrity metadata
133 * @bio: bio to update
134 * @page: page containing integrity metadata
135 * @len: number of bytes of integrity metadata in page
136 * @offset: start offset within page
137 *
138 * Description: Attach a page containing integrity metadata to bio.
139 */
bio_integrity_add_page(struct bio * bio,struct page * page,unsigned int len,unsigned int offset)140 int bio_integrity_add_page(struct bio *bio, struct page *page,
141 unsigned int len, unsigned int offset)
142 {
143 struct bio_integrity_payload *bip = bio_integrity(bio);
144 struct bio_vec *iv;
145
146 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
147 printk(KERN_ERR "%s: bip_vec full\n", __func__);
148 return 0;
149 }
150
151 iv = bip->bip_vec + bip->bip_vcnt;
152
153 if (bip->bip_vcnt &&
154 bvec_gap_to_prev(bio->bi_disk->queue,
155 &bip->bip_vec[bip->bip_vcnt - 1], offset))
156 return 0;
157
158 iv->bv_page = page;
159 iv->bv_len = len;
160 iv->bv_offset = offset;
161 bip->bip_vcnt++;
162
163 return len;
164 }
165 EXPORT_SYMBOL(bio_integrity_add_page);
166
167 /**
168 * bio_integrity_process - Process integrity metadata for a bio
169 * @bio: bio to generate/verify integrity metadata for
170 * @proc_iter: iterator to process
171 * @proc_fn: Pointer to the relevant processing function
172 */
bio_integrity_process(struct bio * bio,struct bvec_iter * proc_iter,integrity_processing_fn * proc_fn)173 static blk_status_t bio_integrity_process(struct bio *bio,
174 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
175 {
176 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
177 struct blk_integrity_iter iter;
178 struct bvec_iter bviter;
179 struct bio_vec bv;
180 struct bio_integrity_payload *bip = bio_integrity(bio);
181 blk_status_t ret = BLK_STS_OK;
182 void *prot_buf = page_address(bip->bip_vec->bv_page) +
183 bip->bip_vec->bv_offset;
184
185 iter.disk_name = bio->bi_disk->disk_name;
186 iter.interval = 1 << bi->interval_exp;
187 iter.seed = proc_iter->bi_sector;
188 iter.prot_buf = prot_buf;
189
190 __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
191 void *kaddr = kmap_atomic(bv.bv_page);
192
193 iter.data_buf = kaddr + bv.bv_offset;
194 iter.data_size = bv.bv_len;
195
196 ret = proc_fn(&iter);
197 if (ret) {
198 kunmap_atomic(kaddr);
199 return ret;
200 }
201
202 kunmap_atomic(kaddr);
203 }
204 return ret;
205 }
206
207 /**
208 * bio_integrity_prep - Prepare bio for integrity I/O
209 * @bio: bio to prepare
210 *
211 * Description: Checks if the bio already has an integrity payload attached.
212 * If it does, the payload has been generated by another kernel subsystem,
213 * and we just pass it through. Otherwise allocates integrity payload.
214 * The bio must have data direction, target device and start sector set priot
215 * to calling. In the WRITE case, integrity metadata will be generated using
216 * the block device's integrity function. In the READ case, the buffer
217 * will be prepared for DMA and a suitable end_io handler set up.
218 */
bio_integrity_prep(struct bio * bio)219 bool bio_integrity_prep(struct bio *bio)
220 {
221 struct bio_integrity_payload *bip;
222 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
223 struct request_queue *q = bio->bi_disk->queue;
224 void *buf;
225 unsigned long start, end;
226 unsigned int len, nr_pages;
227 unsigned int bytes, offset, i;
228 unsigned int intervals;
229 blk_status_t status;
230
231 if (!bi)
232 return true;
233
234 if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
235 return true;
236
237 if (!bio_sectors(bio))
238 return true;
239
240 /* Already protected? */
241 if (bio_integrity(bio))
242 return true;
243
244 if (bio_data_dir(bio) == READ) {
245 if (!bi->profile->verify_fn ||
246 !(bi->flags & BLK_INTEGRITY_VERIFY))
247 return true;
248 } else {
249 if (!bi->profile->generate_fn ||
250 !(bi->flags & BLK_INTEGRITY_GENERATE))
251 return true;
252 }
253 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
254
255 /* Allocate kernel buffer for protection data */
256 len = intervals * bi->tuple_size;
257 buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
258 status = BLK_STS_RESOURCE;
259 if (unlikely(buf == NULL)) {
260 printk(KERN_ERR "could not allocate integrity buffer\n");
261 goto err_end_io;
262 }
263
264 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
265 start = ((unsigned long) buf) >> PAGE_SHIFT;
266 nr_pages = end - start;
267
268 /* Allocate bio integrity payload and integrity vectors */
269 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
270 if (IS_ERR(bip)) {
271 printk(KERN_ERR "could not allocate data integrity bioset\n");
272 kfree(buf);
273 status = BLK_STS_RESOURCE;
274 goto err_end_io;
275 }
276
277 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
278 bip->bip_iter.bi_size = len;
279 bip_set_seed(bip, bio->bi_iter.bi_sector);
280
281 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
282 bip->bip_flags |= BIP_IP_CHECKSUM;
283
284 /* Map it */
285 offset = offset_in_page(buf);
286 for (i = 0 ; i < nr_pages ; i++) {
287 int ret;
288 bytes = PAGE_SIZE - offset;
289
290 if (len <= 0)
291 break;
292
293 if (bytes > len)
294 bytes = len;
295
296 ret = bio_integrity_add_page(bio, virt_to_page(buf),
297 bytes, offset);
298
299 if (ret == 0) {
300 printk(KERN_ERR "could not attach integrity payload\n");
301 status = BLK_STS_RESOURCE;
302 goto err_end_io;
303 }
304
305 if (ret < bytes)
306 break;
307
308 buf += bytes;
309 len -= bytes;
310 offset = 0;
311 }
312
313 /* Auto-generate integrity metadata if this is a write */
314 if (bio_data_dir(bio) == WRITE) {
315 bio_integrity_process(bio, &bio->bi_iter,
316 bi->profile->generate_fn);
317 }
318 return true;
319
320 err_end_io:
321 bio->bi_status = status;
322 bio_endio(bio);
323 return false;
324
325 }
326 EXPORT_SYMBOL(bio_integrity_prep);
327
328 /**
329 * bio_integrity_verify_fn - Integrity I/O completion worker
330 * @work: Work struct stored in bio to be verified
331 *
332 * Description: This workqueue function is called to complete a READ
333 * request. The function verifies the transferred integrity metadata
334 * and then calls the original bio end_io function.
335 */
bio_integrity_verify_fn(struct work_struct * work)336 static void bio_integrity_verify_fn(struct work_struct *work)
337 {
338 struct bio_integrity_payload *bip =
339 container_of(work, struct bio_integrity_payload, bip_work);
340 struct bio *bio = bip->bip_bio;
341 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
342 struct bvec_iter iter = bio->bi_iter;
343
344 /*
345 * At the moment verify is called bio's iterator was advanced
346 * during split and completion, we need to rewind iterator to
347 * it's original position.
348 */
349 if (bio_rewind_iter(bio, &iter, iter.bi_done)) {
350 bio->bi_status = bio_integrity_process(bio, &iter,
351 bi->profile->verify_fn);
352 } else {
353 bio->bi_status = BLK_STS_IOERR;
354 }
355
356 bio_integrity_free(bio);
357 bio_endio(bio);
358 }
359
360 /**
361 * __bio_integrity_endio - Integrity I/O completion function
362 * @bio: Protected bio
363 *
364 * Description: Completion for integrity I/O
365 *
366 * Normally I/O completion is done in interrupt context. However,
367 * verifying I/O integrity is a time-consuming task which must be run
368 * in process context. This function postpones completion
369 * accordingly.
370 */
__bio_integrity_endio(struct bio * bio)371 bool __bio_integrity_endio(struct bio *bio)
372 {
373 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
374 struct bio_integrity_payload *bip = bio_integrity(bio);
375
376 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
377 (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
378 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
379 queue_work(kintegrityd_wq, &bip->bip_work);
380 return false;
381 }
382
383 bio_integrity_free(bio);
384 return true;
385 }
386
387 /**
388 * bio_integrity_advance - Advance integrity vector
389 * @bio: bio whose integrity vector to update
390 * @bytes_done: number of data bytes that have been completed
391 *
392 * Description: This function calculates how many integrity bytes the
393 * number of completed data bytes correspond to and advances the
394 * integrity vector accordingly.
395 */
bio_integrity_advance(struct bio * bio,unsigned int bytes_done)396 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
397 {
398 struct bio_integrity_payload *bip = bio_integrity(bio);
399 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
400 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
401
402 bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
403 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
404 }
405 EXPORT_SYMBOL(bio_integrity_advance);
406
407 /**
408 * bio_integrity_trim - Trim integrity vector
409 * @bio: bio whose integrity vector to update
410 *
411 * Description: Used to trim the integrity vector in a cloned bio.
412 */
bio_integrity_trim(struct bio * bio)413 void bio_integrity_trim(struct bio *bio)
414 {
415 struct bio_integrity_payload *bip = bio_integrity(bio);
416 struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
417
418 bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
419 }
420 EXPORT_SYMBOL(bio_integrity_trim);
421
422 /**
423 * bio_integrity_clone - Callback for cloning bios with integrity metadata
424 * @bio: New bio
425 * @bio_src: Original bio
426 * @gfp_mask: Memory allocation mask
427 *
428 * Description: Called to allocate a bip when cloning a bio
429 */
bio_integrity_clone(struct bio * bio,struct bio * bio_src,gfp_t gfp_mask)430 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
431 gfp_t gfp_mask)
432 {
433 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
434 struct bio_integrity_payload *bip;
435
436 BUG_ON(bip_src == NULL);
437
438 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
439 if (IS_ERR(bip))
440 return PTR_ERR(bip);
441
442 memcpy(bip->bip_vec, bip_src->bip_vec,
443 bip_src->bip_vcnt * sizeof(struct bio_vec));
444
445 bip->bip_vcnt = bip_src->bip_vcnt;
446 bip->bip_iter = bip_src->bip_iter;
447 bip->bip_flags = bip_src->bip_flags & ~BIP_BLOCK_INTEGRITY;
448
449 return 0;
450 }
451 EXPORT_SYMBOL(bio_integrity_clone);
452
bioset_integrity_create(struct bio_set * bs,int pool_size)453 int bioset_integrity_create(struct bio_set *bs, int pool_size)
454 {
455 if (mempool_initialized(&bs->bio_integrity_pool))
456 return 0;
457
458 if (mempool_init_slab_pool(&bs->bio_integrity_pool,
459 pool_size, bip_slab))
460 return -1;
461
462 if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
463 mempool_exit(&bs->bio_integrity_pool);
464 return -1;
465 }
466
467 return 0;
468 }
469 EXPORT_SYMBOL(bioset_integrity_create);
470
bioset_integrity_free(struct bio_set * bs)471 void bioset_integrity_free(struct bio_set *bs)
472 {
473 mempool_exit(&bs->bio_integrity_pool);
474 mempool_exit(&bs->bvec_integrity_pool);
475 }
476 EXPORT_SYMBOL(bioset_integrity_free);
477
bio_integrity_init(void)478 void __init bio_integrity_init(void)
479 {
480 /*
481 * kintegrityd won't block much but may burn a lot of CPU cycles.
482 * Make it highpri CPU intensive wq with max concurrency of 1.
483 */
484 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
485 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
486 if (!kintegrityd_wq)
487 panic("Failed to create kintegrityd\n");
488
489 bip_slab = kmem_cache_create("bio_integrity_payload",
490 sizeof(struct bio_integrity_payload) +
491 sizeof(struct bio_vec) * BIP_INLINE_VECS,
492 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
493 }
494