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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 | int blk_integrity_merge_rq(struct request_queue *q, struct request *req, | |
190 | struct request *next) | |
191 | { | |
192 | if (blk_integrity_rq(req) != blk_integrity_rq(next)) | |
193 | return -1; | |
194 | ||
195 | if (req->nr_integrity_segments + next->nr_integrity_segments > | |
196 | q->limits.max_integrity_segments) | |
197 | return -1; | |
198 | ||
199 | return 0; | |
200 | } | |
201 | EXPORT_SYMBOL(blk_integrity_merge_rq); | |
202 | ||
203 | int blk_integrity_merge_bio(struct request_queue *q, struct request *req, | |
204 | struct bio *bio) | |
205 | { | |
206 | int nr_integrity_segs; | |
207 | struct bio *next = bio->bi_next; | |
208 | ||
209 | bio->bi_next = NULL; | |
210 | nr_integrity_segs = blk_rq_count_integrity_sg(q, bio); | |
211 | bio->bi_next = next; | |
212 | ||
213 | if (req->nr_integrity_segments + nr_integrity_segs > | |
214 | q->limits.max_integrity_segments) | |
215 | return -1; | |
216 | ||
217 | req->nr_integrity_segments += nr_integrity_segs; | |
218 | ||
219 | return 0; | |
220 | } | |
221 | EXPORT_SYMBOL(blk_integrity_merge_bio); | |
222 | ||
223 | struct integrity_sysfs_entry { | |
224 | struct attribute attr; | |
225 | ssize_t (*show)(struct blk_integrity *, char *); | |
226 | ssize_t (*store)(struct blk_integrity *, const char *, size_t); | |
227 | }; | |
228 | ||
229 | static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr, | |
230 | char *page) | |
231 | { | |
232 | struct blk_integrity *bi = | |
233 | container_of(kobj, struct blk_integrity, kobj); | |
234 | struct integrity_sysfs_entry *entry = | |
235 | container_of(attr, struct integrity_sysfs_entry, attr); | |
236 | ||
237 | return entry->show(bi, page); | |
238 | } | |
239 | ||
240 | static ssize_t integrity_attr_store(struct kobject *kobj, | |
241 | struct attribute *attr, const char *page, | |
242 | size_t count) | |
243 | { | |
244 | struct blk_integrity *bi = | |
245 | container_of(kobj, struct blk_integrity, kobj); | |
246 | struct integrity_sysfs_entry *entry = | |
247 | container_of(attr, struct integrity_sysfs_entry, attr); | |
248 | ssize_t ret = 0; | |
249 | ||
250 | if (entry->store) | |
251 | ret = entry->store(bi, page, count); | |
252 | ||
253 | return ret; | |
254 | } | |
255 | ||
256 | static ssize_t integrity_format_show(struct blk_integrity *bi, char *page) | |
257 | { | |
258 | if (bi != NULL && bi->name != NULL) | |
259 | return sprintf(page, "%s\n", bi->name); | |
260 | else | |
261 | return sprintf(page, "none\n"); | |
262 | } | |
263 | ||
264 | static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page) | |
265 | { | |
266 | if (bi != NULL) | |
267 | return sprintf(page, "%u\n", bi->tag_size); | |
268 | else | |
269 | return sprintf(page, "0\n"); | |
270 | } | |
271 | ||
272 | static ssize_t integrity_verify_store(struct blk_integrity *bi, | |
273 | const char *page, size_t count) | |
274 | { | |
275 | char *p = (char *) page; | |
276 | unsigned long val = simple_strtoul(p, &p, 10); | |
277 | ||
278 | if (val) | |
279 | bi->flags |= BLK_INTEGRITY_VERIFY; | |
280 | else | |
281 | bi->flags &= ~BLK_INTEGRITY_VERIFY; | |
282 | ||
283 | return count; | |
284 | } | |
285 | ||
286 | static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page) | |
287 | { | |
288 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0); | |
289 | } | |
290 | ||
291 | static ssize_t integrity_generate_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_GENERATE; | |
299 | else | |
300 | bi->flags &= ~BLK_INTEGRITY_GENERATE; | |
301 | ||
302 | return count; | |
303 | } | |
304 | ||
305 | static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page) | |
306 | { | |
307 | return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0); | |
308 | } | |
309 | ||
310 | static ssize_t integrity_device_show(struct blk_integrity *bi, char *page) | |
311 | { | |
312 | return sprintf(page, "%u\n", | |
313 | (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0); | |
314 | } | |
315 | ||
316 | static struct integrity_sysfs_entry integrity_format_entry = { | |
317 | .attr = { .name = "format", .mode = S_IRUGO }, | |
318 | .show = integrity_format_show, | |
319 | }; | |
320 | ||
321 | static struct integrity_sysfs_entry integrity_tag_size_entry = { | |
322 | .attr = { .name = "tag_size", .mode = S_IRUGO }, | |
323 | .show = integrity_tag_size_show, | |
324 | }; | |
325 | ||
326 | static struct integrity_sysfs_entry integrity_verify_entry = { | |
327 | .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, | |
328 | .show = integrity_verify_show, | |
329 | .store = integrity_verify_store, | |
330 | }; | |
331 | ||
332 | static struct integrity_sysfs_entry integrity_generate_entry = { | |
333 | .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, | |
334 | .show = integrity_generate_show, | |
335 | .store = integrity_generate_store, | |
336 | }; | |
337 | ||
338 | static struct integrity_sysfs_entry integrity_device_entry = { | |
339 | .attr = { .name = "device_is_integrity_capable", .mode = S_IRUGO }, | |
340 | .show = integrity_device_show, | |
341 | }; | |
342 | ||
343 | static struct attribute *integrity_attrs[] = { | |
344 | &integrity_format_entry.attr, | |
345 | &integrity_tag_size_entry.attr, | |
346 | &integrity_verify_entry.attr, | |
347 | &integrity_generate_entry.attr, | |
348 | &integrity_device_entry.attr, | |
349 | NULL, | |
350 | }; | |
351 | ||
352 | static const struct sysfs_ops integrity_ops = { | |
353 | .show = &integrity_attr_show, | |
354 | .store = &integrity_attr_store, | |
355 | }; | |
356 | ||
357 | static int __init blk_dev_integrity_init(void) | |
358 | { | |
359 | integrity_cachep = kmem_cache_create("blkdev_integrity", | |
360 | sizeof(struct blk_integrity), | |
361 | 0, SLAB_PANIC, NULL); | |
362 | return 0; | |
363 | } | |
364 | subsys_initcall(blk_dev_integrity_init); | |
365 | ||
366 | static void blk_integrity_release(struct kobject *kobj) | |
367 | { | |
368 | struct blk_integrity *bi = | |
369 | container_of(kobj, struct blk_integrity, kobj); | |
370 | ||
371 | kmem_cache_free(integrity_cachep, bi); | |
372 | } | |
373 | ||
374 | static struct kobj_type integrity_ktype = { | |
375 | .default_attrs = integrity_attrs, | |
376 | .sysfs_ops = &integrity_ops, | |
377 | .release = blk_integrity_release, | |
378 | }; | |
379 | ||
380 | bool blk_integrity_is_initialized(struct gendisk *disk) | |
381 | { | |
382 | struct blk_integrity *bi = blk_get_integrity(disk); | |
383 | ||
384 | return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0); | |
385 | } | |
386 | EXPORT_SYMBOL(blk_integrity_is_initialized); | |
387 | ||
388 | /** | |
389 | * blk_integrity_register - Register a gendisk as being integrity-capable | |
390 | * @disk: struct gendisk pointer to make integrity-aware | |
391 | * @template: optional integrity profile to register | |
392 | * | |
393 | * Description: When a device needs to advertise itself as being able | |
394 | * to send/receive integrity metadata it must use this function to | |
395 | * register the capability with the block layer. The template is a | |
396 | * blk_integrity struct with values appropriate for the underlying | |
397 | * hardware. If template is NULL the new profile is allocated but | |
398 | * not filled out. See Documentation/block/data-integrity.txt. | |
399 | */ | |
400 | int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) | |
401 | { | |
402 | struct blk_integrity *bi; | |
403 | ||
404 | BUG_ON(disk == NULL); | |
405 | ||
406 | if (disk->integrity == NULL) { | |
407 | bi = kmem_cache_alloc(integrity_cachep, | |
408 | GFP_KERNEL | __GFP_ZERO); | |
409 | if (!bi) | |
410 | return -1; | |
411 | ||
412 | if (kobject_init_and_add(&bi->kobj, &integrity_ktype, | |
413 | &disk_to_dev(disk)->kobj, | |
414 | "%s", "integrity")) { | |
415 | kmem_cache_free(integrity_cachep, bi); | |
416 | return -1; | |
417 | } | |
418 | ||
419 | kobject_uevent(&bi->kobj, KOBJ_ADD); | |
420 | ||
421 | bi->flags |= BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE; | |
422 | bi->interval = queue_logical_block_size(disk->queue); | |
423 | disk->integrity = bi; | |
424 | } else | |
425 | bi = disk->integrity; | |
426 | ||
427 | /* Use the provided profile as template */ | |
428 | if (template != NULL) { | |
429 | bi->name = template->name; | |
430 | bi->generate_fn = template->generate_fn; | |
431 | bi->verify_fn = template->verify_fn; | |
432 | bi->tuple_size = template->tuple_size; | |
433 | bi->tag_size = template->tag_size; | |
434 | bi->flags |= template->flags; | |
435 | } else | |
436 | bi->name = bi_unsupported_name; | |
437 | ||
438 | disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES; | |
439 | ||
440 | return 0; | |
441 | } | |
442 | EXPORT_SYMBOL(blk_integrity_register); | |
443 | ||
444 | /** | |
445 | * blk_integrity_unregister - Remove block integrity profile | |
446 | * @disk: disk whose integrity profile to deallocate | |
447 | * | |
448 | * Description: This function frees all memory used by the block | |
449 | * integrity profile. To be called at device teardown. | |
450 | */ | |
451 | void blk_integrity_unregister(struct gendisk *disk) | |
452 | { | |
453 | struct blk_integrity *bi; | |
454 | ||
455 | if (!disk || !disk->integrity) | |
456 | return; | |
457 | ||
458 | disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES; | |
459 | ||
460 | bi = disk->integrity; | |
461 | ||
462 | kobject_uevent(&bi->kobj, KOBJ_REMOVE); | |
463 | kobject_del(&bi->kobj); | |
464 | kobject_put(&bi->kobj); | |
465 | disk->integrity = NULL; | |
466 | } | |
467 | EXPORT_SYMBOL(blk_integrity_unregister); |