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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
17static struct kmem_cache *bip_slab;
18static struct workqueue_struct *kintegrityd_wq;
19
20void blk_flush_integrity(void)
21{
22 flush_workqueue(kintegrityd_wq);
23}
24
25static 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 */
48struct 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;
88err:
89 __bio_integrity_free(bs, bip);
90 return ERR_PTR(-ENOMEM);
91}
92EXPORT_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 */
101void 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 */
123int 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 struct bio_vec *iv;
128
129 if (bip->bip_vcnt >= bip->bip_max_vcnt) {
130 printk(KERN_ERR "%s: bip_vec full\n", __func__);
131 return 0;
132 }
133
134 iv = bip->bip_vec + bip->bip_vcnt;
135
136 if (bip->bip_vcnt &&
137 bvec_gap_to_prev(&bdev_get_queue(bio->bi_bdev)->limits,
138 &bip->bip_vec[bip->bip_vcnt - 1], offset))
139 return 0;
140
141 iv->bv_page = page;
142 iv->bv_len = len;
143 iv->bv_offset = offset;
144 bip->bip_vcnt++;
145
146 return len;
147}
148EXPORT_SYMBOL(bio_integrity_add_page);
149
150/**
151 * bio_integrity_process - Process integrity metadata for a bio
152 * @bio: bio to generate/verify integrity metadata for
153 * @proc_iter: iterator to process
154 * @proc_fn: Pointer to the relevant processing function
155 */
156static blk_status_t bio_integrity_process(struct bio *bio,
157 struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
158{
159 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
160 struct blk_integrity_iter iter;
161 struct bvec_iter bviter;
162 struct bio_vec bv;
163 struct bio_integrity_payload *bip = bio_integrity(bio);
164 blk_status_t ret = BLK_STS_OK;
165
166 iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
167 iter.interval = 1 << bi->interval_exp;
168 iter.tuple_size = bi->tuple_size;
169 iter.seed = proc_iter->bi_sector;
170 iter.prot_buf = bvec_virt(bip->bip_vec);
171
172 __bio_for_each_segment(bv, bio, bviter, *proc_iter) {
173 void *kaddr = bvec_kmap_local(&bv);
174
175 iter.data_buf = kaddr;
176 iter.data_size = bv.bv_len;
177 ret = proc_fn(&iter);
178 kunmap_local(kaddr);
179
180 if (ret)
181 break;
182
183 }
184 return ret;
185}
186
187/**
188 * bio_integrity_prep - Prepare bio for integrity I/O
189 * @bio: bio to prepare
190 *
191 * Description: Checks if the bio already has an integrity payload attached.
192 * If it does, the payload has been generated by another kernel subsystem,
193 * and we just pass it through. Otherwise allocates integrity payload.
194 * The bio must have data direction, target device and start sector set priot
195 * to calling. In the WRITE case, integrity metadata will be generated using
196 * the block device's integrity function. In the READ case, the buffer
197 * will be prepared for DMA and a suitable end_io handler set up.
198 */
199bool bio_integrity_prep(struct bio *bio)
200{
201 struct bio_integrity_payload *bip;
202 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
203 void *buf;
204 unsigned long start, end;
205 unsigned int len, nr_pages;
206 unsigned int bytes, offset, i;
207 unsigned int intervals;
208 blk_status_t status;
209
210 if (!bi)
211 return true;
212
213 if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
214 return true;
215
216 if (!bio_sectors(bio))
217 return true;
218
219 /* Already protected? */
220 if (bio_integrity(bio))
221 return true;
222
223 if (bio_data_dir(bio) == READ) {
224 if (!bi->profile->verify_fn ||
225 !(bi->flags & BLK_INTEGRITY_VERIFY))
226 return true;
227 } else {
228 if (!bi->profile->generate_fn ||
229 !(bi->flags & BLK_INTEGRITY_GENERATE))
230 return true;
231 }
232 intervals = bio_integrity_intervals(bi, bio_sectors(bio));
233
234 /* Allocate kernel buffer for protection data */
235 len = intervals * bi->tuple_size;
236 buf = kmalloc(len, GFP_NOIO);
237 status = BLK_STS_RESOURCE;
238 if (unlikely(buf == NULL)) {
239 printk(KERN_ERR "could not allocate integrity buffer\n");
240 goto err_end_io;
241 }
242
243 end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
244 start = ((unsigned long) buf) >> PAGE_SHIFT;
245 nr_pages = end - start;
246
247 /* Allocate bio integrity payload and integrity vectors */
248 bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
249 if (IS_ERR(bip)) {
250 printk(KERN_ERR "could not allocate data integrity bioset\n");
251 kfree(buf);
252 status = BLK_STS_RESOURCE;
253 goto err_end_io;
254 }
255
256 bip->bip_flags |= BIP_BLOCK_INTEGRITY;
257 bip->bip_iter.bi_size = len;
258 bip_set_seed(bip, bio->bi_iter.bi_sector);
259
260 if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
261 bip->bip_flags |= BIP_IP_CHECKSUM;
262
263 /* Map it */
264 offset = offset_in_page(buf);
265 for (i = 0 ; i < nr_pages ; i++) {
266 int ret;
267 bytes = PAGE_SIZE - offset;
268
269 if (len <= 0)
270 break;
271
272 if (bytes > len)
273 bytes = len;
274
275 ret = bio_integrity_add_page(bio, virt_to_page(buf),
276 bytes, offset);
277
278 if (ret == 0) {
279 printk(KERN_ERR "could not attach integrity payload\n");
280 status = BLK_STS_RESOURCE;
281 goto err_end_io;
282 }
283
284 if (ret < bytes)
285 break;
286
287 buf += bytes;
288 len -= bytes;
289 offset = 0;
290 }
291
292 /* Auto-generate integrity metadata if this is a write */
293 if (bio_data_dir(bio) == WRITE) {
294 bio_integrity_process(bio, &bio->bi_iter,
295 bi->profile->generate_fn);
296 } else {
297 bip->bio_iter = bio->bi_iter;
298 }
299 return true;
300
301err_end_io:
302 bio->bi_status = status;
303 bio_endio(bio);
304 return false;
305
306}
307EXPORT_SYMBOL(bio_integrity_prep);
308
309/**
310 * bio_integrity_verify_fn - Integrity I/O completion worker
311 * @work: Work struct stored in bio to be verified
312 *
313 * Description: This workqueue function is called to complete a READ
314 * request. The function verifies the transferred integrity metadata
315 * and then calls the original bio end_io function.
316 */
317static void bio_integrity_verify_fn(struct work_struct *work)
318{
319 struct bio_integrity_payload *bip =
320 container_of(work, struct bio_integrity_payload, bip_work);
321 struct bio *bio = bip->bip_bio;
322 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
323
324 /*
325 * At the moment verify is called bio's iterator was advanced
326 * during split and completion, we need to rewind iterator to
327 * it's original position.
328 */
329 bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
330 bi->profile->verify_fn);
331 bio_integrity_free(bio);
332 bio_endio(bio);
333}
334
335/**
336 * __bio_integrity_endio - Integrity I/O completion function
337 * @bio: Protected bio
338 *
339 * Description: Completion for integrity I/O
340 *
341 * Normally I/O completion is done in interrupt context. However,
342 * verifying I/O integrity is a time-consuming task which must be run
343 * in process context. This function postpones completion
344 * accordingly.
345 */
346bool __bio_integrity_endio(struct bio *bio)
347{
348 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
349 struct bio_integrity_payload *bip = bio_integrity(bio);
350
351 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
352 (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
353 INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
354 queue_work(kintegrityd_wq, &bip->bip_work);
355 return false;
356 }
357
358 bio_integrity_free(bio);
359 return true;
360}
361
362/**
363 * bio_integrity_advance - Advance integrity vector
364 * @bio: bio whose integrity vector to update
365 * @bytes_done: number of data bytes that have been completed
366 *
367 * Description: This function calculates how many integrity bytes the
368 * number of completed data bytes correspond to and advances the
369 * integrity vector accordingly.
370 */
371void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
372{
373 struct bio_integrity_payload *bip = bio_integrity(bio);
374 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
375 unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
376
377 bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
378 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
379}
380
381/**
382 * bio_integrity_trim - Trim integrity vector
383 * @bio: bio whose integrity vector to update
384 *
385 * Description: Used to trim the integrity vector in a cloned bio.
386 */
387void bio_integrity_trim(struct bio *bio)
388{
389 struct bio_integrity_payload *bip = bio_integrity(bio);
390 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
391
392 bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
393}
394EXPORT_SYMBOL(bio_integrity_trim);
395
396/**
397 * bio_integrity_clone - Callback for cloning bios with integrity metadata
398 * @bio: New bio
399 * @bio_src: Original bio
400 * @gfp_mask: Memory allocation mask
401 *
402 * Description: Called to allocate a bip when cloning a bio
403 */
404int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
405 gfp_t gfp_mask)
406{
407 struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
408 struct bio_integrity_payload *bip;
409
410 BUG_ON(bip_src == NULL);
411
412 bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
413 if (IS_ERR(bip))
414 return PTR_ERR(bip);
415
416 memcpy(bip->bip_vec, bip_src->bip_vec,
417 bip_src->bip_vcnt * sizeof(struct bio_vec));
418
419 bip->bip_vcnt = bip_src->bip_vcnt;
420 bip->bip_iter = bip_src->bip_iter;
421
422 return 0;
423}
424
425int bioset_integrity_create(struct bio_set *bs, int pool_size)
426{
427 if (mempool_initialized(&bs->bio_integrity_pool))
428 return 0;
429
430 if (mempool_init_slab_pool(&bs->bio_integrity_pool,
431 pool_size, bip_slab))
432 return -1;
433
434 if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
435 mempool_exit(&bs->bio_integrity_pool);
436 return -1;
437 }
438
439 return 0;
440}
441EXPORT_SYMBOL(bioset_integrity_create);
442
443void bioset_integrity_free(struct bio_set *bs)
444{
445 mempool_exit(&bs->bio_integrity_pool);
446 mempool_exit(&bs->bvec_integrity_pool);
447}
448
449void __init bio_integrity_init(void)
450{
451 /*
452 * kintegrityd won't block much but may burn a lot of CPU cycles.
453 * Make it highpri CPU intensive wq with max concurrency of 1.
454 */
455 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
456 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
457 if (!kintegrityd_wq)
458 panic("Failed to create kintegrityd\n");
459
460 bip_slab = kmem_cache_create("bio_integrity_payload",
461 sizeof(struct bio_integrity_payload) +
462 sizeof(struct bio_vec) * BIO_INLINE_VECS,
463 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
464}