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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/mempool.h> |
25 | #include <linux/bio.h> |
26 | #include <linux/scatterlist.h> |
27 | #include <linux/export.h> |
28 | #include <linux/slab.h> |
29 | |
30 | #include "blk.h" |
31 | |
32 | static struct kmem_cache *integrity_cachep; |
33 | |
34 | static const char *bi_unsupported_name = "unsupported"; |
35 | |
36 | /** |
37 | * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements |
38 | * @q: request queue |
39 | * @bio: bio with integrity metadata attached |
40 | * |
41 | * Description: Returns the number of elements required in a |
42 | * scatterlist corresponding to the integrity metadata in a bio. |
43 | */ |
44 | int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio) |
45 | { |
46 | struct bio_vec iv, ivprv = { NULL }; |
47 | unsigned int segments = 0; |
48 | unsigned int seg_size = 0; |
49 | struct bvec_iter iter; |
50 | int prev = 0; |
51 | |
52 | bio_for_each_integrity_vec(iv, bio, iter) { |
53 | |
54 | if (prev) { |
55 | if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv)) |
56 | goto new_segment; |
57 | |
58 | if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv)) |
59 | goto new_segment; |
60 | |
61 | if (seg_size + iv.bv_len > queue_max_segment_size(q)) |
62 | goto new_segment; |
63 | |
64 | seg_size += iv.bv_len; |
65 | } else { |
66 | new_segment: |
67 | segments++; |
68 | seg_size = iv.bv_len; |
69 | } |
70 | |
71 | prev = 1; |
72 | ivprv = iv; |
73 | } |
74 | |
75 | return segments; |
76 | } |
77 | EXPORT_SYMBOL(blk_rq_count_integrity_sg); |
78 | |
79 | /** |
80 | * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist |
81 | * @q: request queue |
82 | * @bio: bio with integrity metadata attached |
83 | * @sglist: target scatterlist |
84 | * |
85 | * Description: Map the integrity vectors in request into a |
86 | * scatterlist. The scatterlist must be big enough to hold all |
87 | * elements. I.e. sized using blk_rq_count_integrity_sg(). |
88 | */ |
89 | int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio, |
90 | struct scatterlist *sglist) |
91 | { |
92 | struct bio_vec iv, ivprv = { NULL }; |
93 | struct scatterlist *sg = NULL; |
94 | unsigned int segments = 0; |
95 | struct bvec_iter iter; |
96 | int prev = 0; |
97 | |
98 | bio_for_each_integrity_vec(iv, bio, iter) { |
99 | |
100 | if (prev) { |
101 | if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv)) |
102 | goto new_segment; |
103 | |
104 | if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv)) |
105 | goto new_segment; |
106 | |
107 | if (sg->length + iv.bv_len > queue_max_segment_size(q)) |
108 | goto new_segment; |
109 | |
110 | sg->length += iv.bv_len; |
111 | } else { |
112 | new_segment: |
113 | if (!sg) |
114 | sg = sglist; |
115 | else { |
116 | sg_unmark_end(sg); |
117 | sg = sg_next(sg); |
118 | } |
119 | |
120 | sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset); |
121 | segments++; |
122 | } |
123 | |
124 | prev = 1; |
125 | ivprv = iv; |
126 | } |
127 | |
128 | if (sg) |
129 | sg_mark_end(sg); |
130 | |
131 | return segments; |
132 | } |
133 | EXPORT_SYMBOL(blk_rq_map_integrity_sg); |
134 | |
135 | /** |
136 | * blk_integrity_compare - Compare integrity profile of two disks |
137 | * @gd1: Disk to compare |
138 | * @gd2: Disk to compare |
139 | * |
140 | * Description: Meta-devices like DM and MD need to verify that all |
141 | * sub-devices use the same integrity format before advertising to |
142 | * upper layers that they can send/receive integrity metadata. This |
143 | * function can be used to check whether two gendisk devices have |
144 | * compatible integrity formats. |
145 | */ |
146 | int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2) |
147 | { |
148 | struct blk_integrity *b1 = gd1->integrity; |
149 | struct blk_integrity *b2 = gd2->integrity; |
150 | |
151 | if (!b1 && !b2) |
152 | return 0; |
153 | |
154 | if (!b1 || !b2) |
155 | return -1; |
156 | |
157 | if (b1->interval != b2->interval) { |
158 | pr_err("%s: %s/%s protection interval %u != %u\n", |
159 | __func__, gd1->disk_name, gd2->disk_name, |
160 | b1->interval, b2->interval); |
161 | return -1; |
162 | } |
163 | |
164 | if (b1->tuple_size != b2->tuple_size) { |
165 | printk(KERN_ERR "%s: %s/%s tuple sz %u != %u\n", __func__, |
166 | gd1->disk_name, gd2->disk_name, |
167 | b1->tuple_size, b2->tuple_size); |
168 | return -1; |
169 | } |
170 | |
171 | if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) { |
172 | printk(KERN_ERR "%s: %s/%s tag sz %u != %u\n", __func__, |
173 | gd1->disk_name, gd2->disk_name, |
174 | b1->tag_size, b2->tag_size); |
175 | return -1; |
176 | } |
177 | |
178 | if (strcmp(b1->name, b2->name)) { |
179 | printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__, |
180 | gd1->disk_name, gd2->disk_name, |
181 | b1->name, b2->name); |
182 | return -1; |
183 | } |
184 | |
185 | return 0; |
186 | } |
187 | EXPORT_SYMBOL(blk_integrity_compare); |
188 | |
189 | bool blk_integrity_merge_rq(struct request_queue *q, struct request *req, |
190 | struct request *next) |
191 | { |
192 | if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0) |
193 | return true; |
194 | |
195 | if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0) |
196 | return false; |
197 | |
198 | if (bio_integrity(req->bio)->bip_flags != |
199 | bio_integrity(next->bio)->bip_flags) |
200 | return false; |
201 | |
202 | if (req->nr_integrity_segments + next->nr_integrity_segments > |
203 | q->limits.max_integrity_segments) |
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 blk_integrity *bi = |
249 | container_of(kobj, struct blk_integrity, kobj); |
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 blk_integrity *bi = |
261 | container_of(kobj, struct blk_integrity, kobj); |
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 != NULL && bi->name != NULL) |
275 | return sprintf(page, "%s\n", bi->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 | if (bi != NULL) |
283 | return sprintf(page, "%u\n", bi->tag_size); |
284 | else |
285 | return sprintf(page, "0\n"); |
286 | } |
287 | |
288 | static ssize_t integrity_verify_store(struct blk_integrity *bi, |
289 | const char *page, size_t count) |
290 | { |
291 | char *p = (char *) page; |
292 | unsigned long val = simple_strtoul(p, &p, 10); |
293 | |
294 | if (val) |
295 | bi->flags |= BLK_INTEGRITY_VERIFY; |
296 | else |
297 | bi->flags &= ~BLK_INTEGRITY_VERIFY; |
298 | |
299 | return count; |
300 | } |
301 | |
302 | static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page) |
303 | { |
304 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0); |
305 | } |
306 | |
307 | static ssize_t integrity_generate_store(struct blk_integrity *bi, |
308 | const char *page, size_t count) |
309 | { |
310 | char *p = (char *) page; |
311 | unsigned long val = simple_strtoul(p, &p, 10); |
312 | |
313 | if (val) |
314 | bi->flags |= BLK_INTEGRITY_GENERATE; |
315 | else |
316 | bi->flags &= ~BLK_INTEGRITY_GENERATE; |
317 | |
318 | return count; |
319 | } |
320 | |
321 | static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page) |
322 | { |
323 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0); |
324 | } |
325 | |
326 | static ssize_t integrity_device_show(struct blk_integrity *bi, char *page) |
327 | { |
328 | return sprintf(page, "%u\n", |
329 | (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0); |
330 | } |
331 | |
332 | static struct integrity_sysfs_entry integrity_format_entry = { |
333 | .attr = { .name = "format", .mode = S_IRUGO }, |
334 | .show = integrity_format_show, |
335 | }; |
336 | |
337 | static struct integrity_sysfs_entry integrity_tag_size_entry = { |
338 | .attr = { .name = "tag_size", .mode = S_IRUGO }, |
339 | .show = integrity_tag_size_show, |
340 | }; |
341 | |
342 | static struct integrity_sysfs_entry integrity_verify_entry = { |
343 | .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, |
344 | .show = integrity_verify_show, |
345 | .store = integrity_verify_store, |
346 | }; |
347 | |
348 | static struct integrity_sysfs_entry integrity_generate_entry = { |
349 | .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, |
350 | .show = integrity_generate_show, |
351 | .store = integrity_generate_store, |
352 | }; |
353 | |
354 | static struct integrity_sysfs_entry integrity_device_entry = { |
355 | .attr = { .name = "device_is_integrity_capable", .mode = S_IRUGO }, |
356 | .show = integrity_device_show, |
357 | }; |
358 | |
359 | static struct attribute *integrity_attrs[] = { |
360 | &integrity_format_entry.attr, |
361 | &integrity_tag_size_entry.attr, |
362 | &integrity_verify_entry.attr, |
363 | &integrity_generate_entry.attr, |
364 | &integrity_device_entry.attr, |
365 | NULL, |
366 | }; |
367 | |
368 | static const struct sysfs_ops integrity_ops = { |
369 | .show = &integrity_attr_show, |
370 | .store = &integrity_attr_store, |
371 | }; |
372 | |
373 | static int __init blk_dev_integrity_init(void) |
374 | { |
375 | integrity_cachep = kmem_cache_create("blkdev_integrity", |
376 | sizeof(struct blk_integrity), |
377 | 0, SLAB_PANIC, NULL); |
378 | return 0; |
379 | } |
380 | subsys_initcall(blk_dev_integrity_init); |
381 | |
382 | static void blk_integrity_release(struct kobject *kobj) |
383 | { |
384 | struct blk_integrity *bi = |
385 | container_of(kobj, struct blk_integrity, kobj); |
386 | |
387 | kmem_cache_free(integrity_cachep, bi); |
388 | } |
389 | |
390 | static struct kobj_type integrity_ktype = { |
391 | .default_attrs = integrity_attrs, |
392 | .sysfs_ops = &integrity_ops, |
393 | .release = blk_integrity_release, |
394 | }; |
395 | |
396 | bool blk_integrity_is_initialized(struct gendisk *disk) |
397 | { |
398 | struct blk_integrity *bi = blk_get_integrity(disk); |
399 | |
400 | return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0); |
401 | } |
402 | EXPORT_SYMBOL(blk_integrity_is_initialized); |
403 | |
404 | /** |
405 | * blk_integrity_register - Register a gendisk as being integrity-capable |
406 | * @disk: struct gendisk pointer to make integrity-aware |
407 | * @template: optional integrity profile to register |
408 | * |
409 | * Description: When a device needs to advertise itself as being able |
410 | * to send/receive integrity metadata it must use this function to |
411 | * register the capability with the block layer. The template is a |
412 | * blk_integrity struct with values appropriate for the underlying |
413 | * hardware. If template is NULL the new profile is allocated but |
414 | * not filled out. See Documentation/block/data-integrity.txt. |
415 | */ |
416 | int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) |
417 | { |
418 | struct blk_integrity *bi; |
419 | |
420 | BUG_ON(disk == NULL); |
421 | |
422 | if (disk->integrity == NULL) { |
423 | bi = kmem_cache_alloc(integrity_cachep, |
424 | GFP_KERNEL | __GFP_ZERO); |
425 | if (!bi) |
426 | return -1; |
427 | |
428 | if (kobject_init_and_add(&bi->kobj, &integrity_ktype, |
429 | &disk_to_dev(disk)->kobj, |
430 | "%s", "integrity")) { |
431 | kmem_cache_free(integrity_cachep, bi); |
432 | return -1; |
433 | } |
434 | |
435 | kobject_uevent(&bi->kobj, KOBJ_ADD); |
436 | |
437 | bi->flags |= BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE; |
438 | bi->interval = queue_logical_block_size(disk->queue); |
439 | disk->integrity = bi; |
440 | } else |
441 | bi = disk->integrity; |
442 | |
443 | /* Use the provided profile as template */ |
444 | if (template != NULL) { |
445 | bi->name = template->name; |
446 | bi->generate_fn = template->generate_fn; |
447 | bi->verify_fn = template->verify_fn; |
448 | bi->tuple_size = template->tuple_size; |
449 | bi->tag_size = template->tag_size; |
450 | bi->flags |= template->flags; |
451 | } else |
452 | bi->name = bi_unsupported_name; |
453 | |
454 | disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES; |
455 | |
456 | return 0; |
457 | } |
458 | EXPORT_SYMBOL(blk_integrity_register); |
459 | |
460 | /** |
461 | * blk_integrity_unregister - Remove block integrity profile |
462 | * @disk: disk whose integrity profile to deallocate |
463 | * |
464 | * Description: This function frees all memory used by the block |
465 | * integrity profile. To be called at device teardown. |
466 | */ |
467 | void blk_integrity_unregister(struct gendisk *disk) |
468 | { |
469 | struct blk_integrity *bi; |
470 | |
471 | if (!disk || !disk->integrity) |
472 | return; |
473 | |
474 | disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES; |
475 | |
476 | bi = disk->integrity; |
477 | |
478 | kobject_uevent(&bi->kobj, KOBJ_REMOVE); |
479 | kobject_del(&bi->kobj); |
480 | kobject_put(&bi->kobj); |
481 | disk->integrity = NULL; |
482 | } |
483 | EXPORT_SYMBOL(blk_integrity_unregister); |
484 |
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