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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 const 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 | } |