1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * bio-integrity.c - bio data integrity extensions
4 *
5 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
6 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
7 */
8
9 #include <linux/blk-integrity.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>
15 #include "blk.h"
16
17 static struct kmem_cache *bip_slab;
18 static struct workqueue_struct *kintegrityd_wq;
19
blk_flush_integrity(void)20 void blk_flush_integrity(void)
21 {
22 flush_workqueue(kintegrityd_wq);
23 }
24
__bio_integrity_free(struct bio_set * bs,struct bio_integrity_payload * bip)25 static void __bio_integrity_free(struct bio_set *bs,
26 struct bio_integrity_payload *bip)
27 {
28 if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
29 if (bip->bip_vec)
30 bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
31 bip->bip_max_vcnt);
32 mempool_free(bip, &bs->bio_integrity_pool);
33 } else {
34 kfree(bip);
35 }
36 }
37
38 /**
39 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
40 * @bio: bio to attach integrity metadata to
41 * @gfp_mask: Memory allocation mask
42 * @nr_vecs: Number of integrity metadata scatter-gather elements
43 *
44 * Description: This function prepares a bio for attaching integrity
45 * metadata. nr_vecs specifies the maximum number of pages containing
46 * integrity metadata that can be attached.
47 */
bio_integrity_alloc(struct bio * bio,gfp_t gfp_mask,unsigned int nr_vecs)48 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
49 gfp_t gfp_mask,
50 unsigned int nr_vecs)
51 {
52 struct bio_integrity_payload *bip;
53 struct bio_set *bs = bio->bi_pool;
54 unsigned inline_vecs;
55
56 if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
57 return ERR_PTR(-EOPNOTSUPP);
58
59 if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
60 bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
61 inline_vecs = nr_vecs;
62 } else {
63 bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
64 inline_vecs = BIO_INLINE_VECS;
65 }
66
67 if (unlikely(!bip))
68 return ERR_PTR(-ENOMEM);
69
70 memset(bip, 0, sizeof(*bip));
71
72 if (nr_vecs > inline_vecs) {
73 bip->bip_max_vcnt = nr_vecs;
74 bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
75 &bip->bip_max_vcnt, gfp_mask);
76 if (!bip->bip_vec)
77 goto err;
78 } else {
79 bip->bip_vec = bip->bip_inline_vecs;
80 bip->bip_max_vcnt = inline_vecs;
81 }
82
83 bip->bip_bio = bio;
84 bio->bi_integrity = bip;
85 bio->bi_opf |= REQ_INTEGRITY;
86
87 return bip;
88 err:
89 __bio_integrity_free(bs, bip);
90 return ERR_PTR(-ENOMEM);
91 }
92 EXPORT_SYMBOL(bio_integrity_alloc);
93
94 /**
95 * bio_integrity_free - Free bio integrity payload
96 * @bio: bio containing bip to be freed
97 *
98 * Description: Used to free the integrity portion of a bio. Usually
99 * called from bio_free().
100 */
bio_integrity_free(struct bio * bio)101 void bio_integrity_free(struct bio *bio)
102 {
103 struct bio_integrity_payload *bip = bio_integrity(bio);
104 struct bio_set *bs = bio->bi_pool;
105
106 if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
107 kfree(bvec_virt(bip->bip_vec));
108
109 __bio_integrity_free(bs, bip);
110 bio->bi_integrity = NULL;
111 bio->bi_opf &= ~REQ_INTEGRITY;
112 }
113
114 /**
115 * bio_integrity_add_page - Attach integrity metadata
116 * @bio: bio to update
117 * @page: page containing integrity metadata
118 * @len: number of bytes of integrity metadata in page
119 * @offset: start offset within page
120 *
121 * Description: Attach a page containing integrity metadata to bio.
122 */
bio_integrity_add_page(struct bio * bio,struct page * page,unsigned int len,unsigned int offset)123 int bio_integrity_add_page(struct bio *bio, struct page *page,
124 unsigned int len, unsigned int offset)
125 {
126 struct bio_integrity_payload *bip = bio_integrity(bio);
127
128 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
129 printk(KERN_ERR "%s: bip_vec full\n", __func__);
130 return 0;
131 }
132
133 if (bip->bip_vcnt &&
134 bvec_gap_to_prev(&bdev_get_queue(bio->bi_bdev)->limits,
135 &bip->bip_vec[bip->bip_vcnt - 1], offset))
136 return 0;
137
138 bvec_set_page(&bip->bip_vec[bip->bip_vcnt], page, len, offset);
139 bip->bip_vcnt++;
140
141 return len;
142 }
143 EXPORT_SYMBOL(bio_integrity_add_page);
144
145 /**
146 * bio_integrity_process - Process integrity metadata for a bio
147 * @bio: bio to generate/verify integrity metadata for
148 * @proc_iter: iterator to process
149 * @proc_fn: Pointer to the relevant processing function
150 */
bio_integrity_process(struct bio * bio,struct bvec_iter * proc_iter,integrity_processing_fn * proc_fn)151 static blk_status_t bio_integrity_process(struct bio *bio,
152 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
153 {
154 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
155 struct blk_integrity_iter iter;
156 struct bvec_iter bviter;
157 struct bio_vec bv;
158 struct bio_integrity_payload *bip = bio_integrity(bio);
159 blk_status_t ret = BLK_STS_OK;
160
161 iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
162 iter.interval = 1 << bi->interval_exp;
163 iter.tuple_size = bi->tuple_size;
164 iter.seed = proc_iter->bi_sector;
165 iter.prot_buf = bvec_virt(bip->bip_vec);
166
167 __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
168 void *kaddr = bvec_kmap_local(&bv);
169
170 iter.data_buf = kaddr;
171 iter.data_size = bv.bv_len;
172 ret = proc_fn(&iter);
173 kunmap_local(kaddr);
174
175 if (ret)
176 break;
177
178 }
179 return ret;
180 }
181
182 /**
183 * bio_integrity_prep - Prepare bio for integrity I/O
184 * @bio: bio to prepare
185 *
186 * Description: Checks if the bio already has an integrity payload attached.
187 * If it does, the payload has been generated by another kernel subsystem,
188 * and we just pass it through. Otherwise allocates integrity payload.
189 * The bio must have data direction, target device and start sector set priot
190 * to calling. In the WRITE case, integrity metadata will be generated using
191 * the block device's integrity function. In the READ case, the buffer
192 * will be prepared for DMA and a suitable end_io handler set up.
193 */
bio_integrity_prep(struct bio * bio)194 bool bio_integrity_prep(struct bio *bio)
195 {
196 struct bio_integrity_payload *bip;
197 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
198 void *buf;
199 unsigned long start, end;
200 unsigned int len, nr_pages;
201 unsigned int bytes, offset, i;
202 unsigned int intervals;
203 blk_status_t status;
204
205 if (!bi)
206 return true;
207
208 if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
209 return true;
210
211 if (!bio_sectors(bio))
212 return true;
213
214 /* Already protected? */
215 if (bio_integrity(bio))
216 return true;
217
218 if (bio_data_dir(bio) == READ) {
219 if (!bi->profile->verify_fn ||
220 !(bi->flags & BLK_INTEGRITY_VERIFY))
221 return true;
222 } else {
223 if (!bi->profile->generate_fn ||
224 !(bi->flags & BLK_INTEGRITY_GENERATE))
225 return true;
226 }
227 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
228
229 /* Allocate kernel buffer for protection data */
230 len = intervals * bi->tuple_size;
231 buf = kmalloc(len, GFP_NOIO);
232 status = BLK_STS_RESOURCE;
233 if (unlikely(buf == NULL)) {
234 printk(KERN_ERR "could not allocate integrity buffer\n");
235 goto err_end_io;
236 }
237
238 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
239 start = ((unsigned long) buf) >> PAGE_SHIFT;
240 nr_pages = end - start;
241
242 /* Allocate bio integrity payload and integrity vectors */
243 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
244 if (IS_ERR(bip)) {
245 printk(KERN_ERR "could not allocate data integrity bioset\n");
246 kfree(buf);
247 status = BLK_STS_RESOURCE;
248 goto err_end_io;
249 }
250
251 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
252 bip->bip_iter.bi_size = len;
253 bip_set_seed(bip, bio->bi_iter.bi_sector);
254
255 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
256 bip->bip_flags |= BIP_IP_CHECKSUM;
257
258 /* Map it */
259 offset = offset_in_page(buf);
260 for (i = 0 ; i < nr_pages ; i++) {
261 int ret;
262 bytes = PAGE_SIZE - offset;
263
264 if (len <= 0)
265 break;
266
267 if (bytes > len)
268 bytes = len;
269
270 ret = bio_integrity_add_page(bio, virt_to_page(buf),
271 bytes, offset);
272
273 if (ret == 0) {
274 printk(KERN_ERR "could not attach integrity payload\n");
275 status = BLK_STS_RESOURCE;
276 goto err_end_io;
277 }
278
279 if (ret < bytes)
280 break;
281
282 buf += bytes;
283 len -= bytes;
284 offset = 0;
285 }
286
287 /* Auto-generate integrity metadata if this is a write */
288 if (bio_data_dir(bio) == WRITE) {
289 bio_integrity_process(bio, &bio->bi_iter,
290 bi->profile->generate_fn);
291 } else {
292 bip->bio_iter = bio->bi_iter;
293 }
294 return true;
295
296 err_end_io:
297 bio->bi_status = status;
298 bio_endio(bio);
299 return false;
300
301 }
302 EXPORT_SYMBOL(bio_integrity_prep);
303
304 /**
305 * bio_integrity_verify_fn - Integrity I/O completion worker
306 * @work: Work struct stored in bio to be verified
307 *
308 * Description: This workqueue function is called to complete a READ
309 * request. The function verifies the transferred integrity metadata
310 * and then calls the original bio end_io function.
311 */
bio_integrity_verify_fn(struct work_struct * work)312 static void bio_integrity_verify_fn(struct work_struct *work)
313 {
314 struct bio_integrity_payload *bip =
315 container_of(work, struct bio_integrity_payload, bip_work);
316 struct bio *bio = bip->bip_bio;
317 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
318
319 /*
320 * At the moment verify is called bio's iterator was advanced
321 * during split and completion, we need to rewind iterator to
322 * it's original position.
323 */
324 bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
325 bi->profile->verify_fn);
326 bio_integrity_free(bio);
327 bio_endio(bio);
328 }
329
330 /**
331 * __bio_integrity_endio - Integrity I/O completion function
332 * @bio: Protected bio
333 *
334 * Description: Completion for integrity I/O
335 *
336 * Normally I/O completion is done in interrupt context. However,
337 * verifying I/O integrity is a time-consuming task which must be run
338 * in process context. This function postpones completion
339 * accordingly.
340 */
__bio_integrity_endio(struct bio * bio)341 bool __bio_integrity_endio(struct bio *bio)
342 {
343 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
344 struct bio_integrity_payload *bip = bio_integrity(bio);
345
346 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
347 (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
348 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
349 queue_work(kintegrityd_wq, &bip->bip_work);
350 return false;
351 }
352
353 bio_integrity_free(bio);
354 return true;
355 }
356
357 /**
358 * bio_integrity_advance - Advance integrity vector
359 * @bio: bio whose integrity vector to update
360 * @bytes_done: number of data bytes that have been completed
361 *
362 * Description: This function calculates how many integrity bytes the
363 * number of completed data bytes correspond to and advances the
364 * integrity vector accordingly.
365 */
bio_integrity_advance(struct bio * bio,unsigned int bytes_done)366 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
367 {
368 struct bio_integrity_payload *bip = bio_integrity(bio);
369 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
370 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
371
372 bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
373 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
374 }
375
376 /**
377 * bio_integrity_trim - Trim integrity vector
378 * @bio: bio whose integrity vector to update
379 *
380 * Description: Used to trim the integrity vector in a cloned bio.
381 */
bio_integrity_trim(struct bio * bio)382 void bio_integrity_trim(struct bio *bio)
383 {
384 struct bio_integrity_payload *bip = bio_integrity(bio);
385 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
386
387 bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
388 }
389 EXPORT_SYMBOL(bio_integrity_trim);
390
391 /**
392 * bio_integrity_clone - Callback for cloning bios with integrity metadata
393 * @bio: New bio
394 * @bio_src: Original bio
395 * @gfp_mask: Memory allocation mask
396 *
397 * Description: Called to allocate a bip when cloning a bio
398 */
bio_integrity_clone(struct bio * bio,struct bio * bio_src,gfp_t gfp_mask)399 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
400 gfp_t gfp_mask)
401 {
402 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
403 struct bio_integrity_payload *bip;
404
405 BUG_ON(bip_src == NULL);
406
407 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
408 if (IS_ERR(bip))
409 return PTR_ERR(bip);
410
411 memcpy(bip->bip_vec, bip_src->bip_vec,
412 bip_src->bip_vcnt * sizeof(struct bio_vec));
413
414 bip->bip_vcnt = bip_src->bip_vcnt;
415 bip->bip_iter = bip_src->bip_iter;
416 bip->bip_flags = bip_src->bip_flags & ~BIP_BLOCK_INTEGRITY;
417
418 return 0;
419 }
420
bioset_integrity_create(struct bio_set * bs,int pool_size)421 int bioset_integrity_create(struct bio_set *bs, int pool_size)
422 {
423 if (mempool_initialized(&bs->bio_integrity_pool))
424 return 0;
425
426 if (mempool_init_slab_pool(&bs->bio_integrity_pool,
427 pool_size, bip_slab))
428 return -1;
429
430 if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
431 mempool_exit(&bs->bio_integrity_pool);
432 return -1;
433 }
434
435 return 0;
436 }
437 EXPORT_SYMBOL(bioset_integrity_create);
438
bioset_integrity_free(struct bio_set * bs)439 void bioset_integrity_free(struct bio_set *bs)
440 {
441 mempool_exit(&bs->bio_integrity_pool);
442 mempool_exit(&bs->bvec_integrity_pool);
443 }
444
bio_integrity_init(void)445 void __init bio_integrity_init(void)
446 {
447 /*
448 * kintegrityd won't block much but may burn a lot of CPU cycles.
449 * Make it highpri CPU intensive wq with max concurrency of 1.
450 */
451 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
452 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
453 if (!kintegrityd_wq)
454 panic("Failed to create kintegrityd\n");
455
456 bip_slab = kmem_cache_create("bio_integrity_payload",
457 sizeof(struct bio_integrity_payload) +
458 sizeof(struct bio_vec) * BIO_INLINE_VECS,
459 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
460 }
461