blob: 478f572cb1e7d6bb78c4dcbbf650012107c6e1a0
1 | /* |
2 | * blk-integrity.c - Block layer data integrity extensions |
3 | * |
4 | * Copyright (C) 2007, 2008 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/backing-dev.h> |
25 | #include <linux/mempool.h> |
26 | #include <linux/bio.h> |
27 | #include <linux/scatterlist.h> |
28 | #include <linux/export.h> |
29 | #include <linux/slab.h> |
30 | |
31 | #include "blk.h" |
32 | |
33 | /** |
34 | * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements |
35 | * @q: request queue |
36 | * @bio: bio with integrity metadata attached |
37 | * |
38 | * Description: Returns the number of elements required in a |
39 | * scatterlist corresponding to the integrity metadata in a bio. |
40 | */ |
41 | int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio) |
42 | { |
43 | struct bio_vec iv, ivprv = { NULL }; |
44 | unsigned int segments = 0; |
45 | unsigned int seg_size = 0; |
46 | struct bvec_iter iter; |
47 | int prev = 0; |
48 | |
49 | bio_for_each_integrity_vec(iv, bio, iter) { |
50 | |
51 | if (prev) { |
52 | if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv)) |
53 | goto new_segment; |
54 | |
55 | if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv)) |
56 | goto new_segment; |
57 | |
58 | if (seg_size + iv.bv_len > queue_max_segment_size(q)) |
59 | goto new_segment; |
60 | |
61 | seg_size += iv.bv_len; |
62 | } else { |
63 | new_segment: |
64 | segments++; |
65 | seg_size = iv.bv_len; |
66 | } |
67 | |
68 | prev = 1; |
69 | ivprv = iv; |
70 | } |
71 | |
72 | return segments; |
73 | } |
74 | EXPORT_SYMBOL(blk_rq_count_integrity_sg); |
75 | |
76 | /** |
77 | * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist |
78 | * @q: request queue |
79 | * @bio: bio with integrity metadata attached |
80 | * @sglist: target scatterlist |
81 | * |
82 | * Description: Map the integrity vectors in request into a |
83 | * scatterlist. The scatterlist must be big enough to hold all |
84 | * elements. I.e. sized using blk_rq_count_integrity_sg(). |
85 | */ |
86 | int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio, |
87 | struct scatterlist *sglist) |
88 | { |
89 | struct bio_vec iv, ivprv = { NULL }; |
90 | struct scatterlist *sg = NULL; |
91 | unsigned int segments = 0; |
92 | struct bvec_iter iter; |
93 | int prev = 0; |
94 | |
95 | bio_for_each_integrity_vec(iv, bio, iter) { |
96 | |
97 | if (prev) { |
98 | if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv)) |
99 | goto new_segment; |
100 | |
101 | if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv)) |
102 | goto new_segment; |
103 | |
104 | if (sg->length + iv.bv_len > queue_max_segment_size(q)) |
105 | goto new_segment; |
106 | |
107 | sg->length += iv.bv_len; |
108 | } else { |
109 | new_segment: |
110 | if (!sg) |
111 | sg = sglist; |
112 | else { |
113 | sg_unmark_end(sg); |
114 | sg = sg_next(sg); |
115 | } |
116 | |
117 | sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset); |
118 | segments++; |
119 | } |
120 | |
121 | prev = 1; |
122 | ivprv = iv; |
123 | } |
124 | |
125 | if (sg) |
126 | sg_mark_end(sg); |
127 | |
128 | return segments; |
129 | } |
130 | EXPORT_SYMBOL(blk_rq_map_integrity_sg); |
131 | |
132 | /** |
133 | * blk_integrity_compare - Compare integrity profile of two disks |
134 | * @gd1: Disk to compare |
135 | * @gd2: Disk to compare |
136 | * |
137 | * Description: Meta-devices like DM and MD need to verify that all |
138 | * sub-devices use the same integrity format before advertising to |
139 | * upper layers that they can send/receive integrity metadata. This |
140 | * function can be used to check whether two gendisk devices have |
141 | * compatible integrity formats. |
142 | */ |
143 | int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2) |
144 | { |
145 | struct blk_integrity *b1 = &gd1->queue->integrity; |
146 | struct blk_integrity *b2 = &gd2->queue->integrity; |
147 | |
148 | if (!b1->profile && !b2->profile) |
149 | return 0; |
150 | |
151 | if (!b1->profile || !b2->profile) |
152 | return -1; |
153 | |
154 | if (b1->interval_exp != b2->interval_exp) { |
155 | pr_err("%s: %s/%s protection interval %u != %u\n", |
156 | __func__, gd1->disk_name, gd2->disk_name, |
157 | 1 << b1->interval_exp, 1 << b2->interval_exp); |
158 | return -1; |
159 | } |
160 | |
161 | if (b1->tuple_size != b2->tuple_size) { |
162 | pr_err("%s: %s/%s tuple sz %u != %u\n", __func__, |
163 | gd1->disk_name, gd2->disk_name, |
164 | b1->tuple_size, b2->tuple_size); |
165 | return -1; |
166 | } |
167 | |
168 | if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) { |
169 | pr_err("%s: %s/%s tag sz %u != %u\n", __func__, |
170 | gd1->disk_name, gd2->disk_name, |
171 | b1->tag_size, b2->tag_size); |
172 | return -1; |
173 | } |
174 | |
175 | if (b1->profile != b2->profile) { |
176 | pr_err("%s: %s/%s type %s != %s\n", __func__, |
177 | gd1->disk_name, gd2->disk_name, |
178 | b1->profile->name, b2->profile->name); |
179 | return -1; |
180 | } |
181 | |
182 | return 0; |
183 | } |
184 | EXPORT_SYMBOL(blk_integrity_compare); |
185 | |
186 | bool blk_integrity_merge_rq(struct request_queue *q, struct request *req, |
187 | struct request *next) |
188 | { |
189 | if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0) |
190 | return true; |
191 | |
192 | if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0) |
193 | return false; |
194 | |
195 | if (bio_integrity(req->bio)->bip_flags != |
196 | bio_integrity(next->bio)->bip_flags) |
197 | return false; |
198 | |
199 | if (req->nr_integrity_segments + next->nr_integrity_segments > |
200 | q->limits.max_integrity_segments) |
201 | return false; |
202 | |
203 | if (integrity_req_gap_back_merge(req, next->bio)) |
204 | return false; |
205 | |
206 | return true; |
207 | } |
208 | EXPORT_SYMBOL(blk_integrity_merge_rq); |
209 | |
210 | bool blk_integrity_merge_bio(struct request_queue *q, struct request *req, |
211 | struct bio *bio) |
212 | { |
213 | int nr_integrity_segs; |
214 | struct bio *next = bio->bi_next; |
215 | |
216 | if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL) |
217 | return true; |
218 | |
219 | if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL) |
220 | return false; |
221 | |
222 | if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags) |
223 | return false; |
224 | |
225 | bio->bi_next = NULL; |
226 | nr_integrity_segs = blk_rq_count_integrity_sg(q, bio); |
227 | bio->bi_next = next; |
228 | |
229 | if (req->nr_integrity_segments + nr_integrity_segs > |
230 | q->limits.max_integrity_segments) |
231 | return false; |
232 | |
233 | req->nr_integrity_segments += nr_integrity_segs; |
234 | |
235 | return true; |
236 | } |
237 | EXPORT_SYMBOL(blk_integrity_merge_bio); |
238 | |
239 | struct integrity_sysfs_entry { |
240 | struct attribute attr; |
241 | ssize_t (*show)(struct blk_integrity *, char *); |
242 | ssize_t (*store)(struct blk_integrity *, const char *, size_t); |
243 | }; |
244 | |
245 | static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr, |
246 | char *page) |
247 | { |
248 | struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj); |
249 | struct blk_integrity *bi = &disk->queue->integrity; |
250 | struct integrity_sysfs_entry *entry = |
251 | container_of(attr, struct integrity_sysfs_entry, attr); |
252 | |
253 | return entry->show(bi, page); |
254 | } |
255 | |
256 | static ssize_t integrity_attr_store(struct kobject *kobj, |
257 | struct attribute *attr, const char *page, |
258 | size_t count) |
259 | { |
260 | struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj); |
261 | struct blk_integrity *bi = &disk->queue->integrity; |
262 | struct integrity_sysfs_entry *entry = |
263 | container_of(attr, struct integrity_sysfs_entry, attr); |
264 | ssize_t ret = 0; |
265 | |
266 | if (entry->store) |
267 | ret = entry->store(bi, page, count); |
268 | |
269 | return ret; |
270 | } |
271 | |
272 | static ssize_t integrity_format_show(struct blk_integrity *bi, char *page) |
273 | { |
274 | if (bi->profile && bi->profile->name) |
275 | return sprintf(page, "%s\n", bi->profile->name); |
276 | else |
277 | return sprintf(page, "none\n"); |
278 | } |
279 | |
280 | static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page) |
281 | { |
282 | return sprintf(page, "%u\n", bi->tag_size); |
283 | } |
284 | |
285 | static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page) |
286 | { |
287 | return sprintf(page, "%u\n", |
288 | bi->interval_exp ? 1 << bi->interval_exp : 0); |
289 | } |
290 | |
291 | static ssize_t integrity_verify_store(struct blk_integrity *bi, |
292 | const char *page, size_t count) |
293 | { |
294 | char *p = (char *) page; |
295 | unsigned long val = simple_strtoul(p, &p, 10); |
296 | |
297 | if (val) |
298 | bi->flags |= BLK_INTEGRITY_VERIFY; |
299 | else |
300 | bi->flags &= ~BLK_INTEGRITY_VERIFY; |
301 | |
302 | return count; |
303 | } |
304 | |
305 | static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page) |
306 | { |
307 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0); |
308 | } |
309 | |
310 | static ssize_t integrity_generate_store(struct blk_integrity *bi, |
311 | const char *page, size_t count) |
312 | { |
313 | char *p = (char *) page; |
314 | unsigned long val = simple_strtoul(p, &p, 10); |
315 | |
316 | if (val) |
317 | bi->flags |= BLK_INTEGRITY_GENERATE; |
318 | else |
319 | bi->flags &= ~BLK_INTEGRITY_GENERATE; |
320 | |
321 | return count; |
322 | } |
323 | |
324 | static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page) |
325 | { |
326 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0); |
327 | } |
328 | |
329 | static ssize_t integrity_device_show(struct blk_integrity *bi, char *page) |
330 | { |
331 | return sprintf(page, "%u\n", |
332 | (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0); |
333 | } |
334 | |
335 | static struct integrity_sysfs_entry integrity_format_entry = { |
336 | .attr = { .name = "format", .mode = S_IRUGO }, |
337 | .show = integrity_format_show, |
338 | }; |
339 | |
340 | static struct integrity_sysfs_entry integrity_tag_size_entry = { |
341 | .attr = { .name = "tag_size", .mode = S_IRUGO }, |
342 | .show = integrity_tag_size_show, |
343 | }; |
344 | |
345 | static struct integrity_sysfs_entry integrity_interval_entry = { |
346 | .attr = { .name = "protection_interval_bytes", .mode = S_IRUGO }, |
347 | .show = integrity_interval_show, |
348 | }; |
349 | |
350 | static struct integrity_sysfs_entry integrity_verify_entry = { |
351 | .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, |
352 | .show = integrity_verify_show, |
353 | .store = integrity_verify_store, |
354 | }; |
355 | |
356 | static struct integrity_sysfs_entry integrity_generate_entry = { |
357 | .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, |
358 | .show = integrity_generate_show, |
359 | .store = integrity_generate_store, |
360 | }; |
361 | |
362 | static struct integrity_sysfs_entry integrity_device_entry = { |
363 | .attr = { .name = "device_is_integrity_capable", .mode = S_IRUGO }, |
364 | .show = integrity_device_show, |
365 | }; |
366 | |
367 | static struct attribute *integrity_attrs[] = { |
368 | &integrity_format_entry.attr, |
369 | &integrity_tag_size_entry.attr, |
370 | &integrity_interval_entry.attr, |
371 | &integrity_verify_entry.attr, |
372 | &integrity_generate_entry.attr, |
373 | &integrity_device_entry.attr, |
374 | NULL, |
375 | }; |
376 | |
377 | static const struct sysfs_ops integrity_ops = { |
378 | .show = &integrity_attr_show, |
379 | .store = &integrity_attr_store, |
380 | }; |
381 | |
382 | static struct kobj_type integrity_ktype = { |
383 | .default_attrs = integrity_attrs, |
384 | .sysfs_ops = &integrity_ops, |
385 | }; |
386 | |
387 | static int blk_integrity_nop_fn(struct blk_integrity_iter *iter) |
388 | { |
389 | return 0; |
390 | } |
391 | |
392 | static struct blk_integrity_profile nop_profile = { |
393 | .name = "nop", |
394 | .generate_fn = blk_integrity_nop_fn, |
395 | .verify_fn = blk_integrity_nop_fn, |
396 | }; |
397 | |
398 | /** |
399 | * blk_integrity_register - Register a gendisk as being integrity-capable |
400 | * @disk: struct gendisk pointer to make integrity-aware |
401 | * @template: block integrity profile to register |
402 | * |
403 | * Description: When a device needs to advertise itself as being able to |
404 | * send/receive integrity metadata it must use this function to register |
405 | * the capability with the block layer. The template is a blk_integrity |
406 | * struct with values appropriate for the underlying hardware. See |
407 | * Documentation/block/data-integrity.txt. |
408 | */ |
409 | void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) |
410 | { |
411 | struct blk_integrity *bi = &disk->queue->integrity; |
412 | |
413 | bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE | |
414 | template->flags; |
415 | bi->interval_exp = template->interval_exp ? : |
416 | ilog2(queue_logical_block_size(disk->queue)); |
417 | bi->profile = template->profile ? template->profile : &nop_profile; |
418 | bi->tuple_size = template->tuple_size; |
419 | bi->tag_size = template->tag_size; |
420 | |
421 | disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES; |
422 | } |
423 | EXPORT_SYMBOL(blk_integrity_register); |
424 | |
425 | /** |
426 | * blk_integrity_unregister - Unregister block integrity profile |
427 | * @disk: disk whose integrity profile to unregister |
428 | * |
429 | * Description: This function unregisters the integrity capability from |
430 | * a block device. |
431 | */ |
432 | void blk_integrity_unregister(struct gendisk *disk) |
433 | { |
434 | disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES; |
435 | memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity)); |
436 | } |
437 | EXPORT_SYMBOL(blk_integrity_unregister); |
438 | |
439 | void blk_integrity_add(struct gendisk *disk) |
440 | { |
441 | if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype, |
442 | &disk_to_dev(disk)->kobj, "%s", "integrity")) |
443 | return; |
444 | |
445 | kobject_uevent(&disk->integrity_kobj, KOBJ_ADD); |
446 | } |
447 | |
448 | void blk_integrity_del(struct gendisk *disk) |
449 | { |
450 | kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE); |
451 | kobject_del(&disk->integrity_kobj); |
452 | kobject_put(&disk->integrity_kobj); |
453 | } |
454 |