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authorMartin K. Petersen <martin.petersen@oracle.com>2008-06-30 14:04:41 -0400
committerJens Axboe <jens.axboe@oracle.com>2008-07-03 07:21:13 -0400
commit7ba1ba12eeef0aa7113beb16410ef8b7c748e18b (patch)
tree4629aabe88bf095d58eabd2f451207695bb35b08 /block/blk-integrity.c
parent51d654e1d885607a6edd02b337105fa5c28b6d33 (diff)
block: Block layer data integrity support
Some block devices support verifying the integrity of requests by way of checksums or other protection information that is submitted along with the I/O. This patch implements support for generating and verifying integrity metadata, as well as correctly merging, splitting and cloning bios and requests that have this extra information attached. See Documentation/block/data-integrity.txt for more information. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-integrity.c')
-rw-r--r--block/blk-integrity.c382
1 files changed, 382 insertions, 0 deletions
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
new file mode 100644
index 000000000000..65f23ef38bbe
--- /dev/null
+++ b/block/blk-integrity.c
@@ -0,0 +1,382 @@
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
28#include "blk.h"
29
30static struct kmem_cache *integrity_cachep;
31
32/**
33 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
34 * @rq: request with integrity metadata attached
35 *
36 * Description: Returns the number of elements required in a
37 * scatterlist corresponding to the integrity metadata in a request.
38 */
39int blk_rq_count_integrity_sg(struct request *rq)
40{
41 struct bio_vec *iv, *ivprv;
42 struct req_iterator iter;
43 unsigned int segments;
44
45 ivprv = NULL;
46 segments = 0;
47
48 rq_for_each_integrity_segment(iv, rq, iter) {
49
50 if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
51 segments++;
52
53 ivprv = iv;
54 }
55
56 return segments;
57}
58EXPORT_SYMBOL(blk_rq_count_integrity_sg);
59
60/**
61 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
62 * @rq: request with integrity metadata attached
63 * @sglist: target scatterlist
64 *
65 * Description: Map the integrity vectors in request into a
66 * scatterlist. The scatterlist must be big enough to hold all
67 * elements. I.e. sized using blk_rq_count_integrity_sg().
68 */
69int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)
70{
71 struct bio_vec *iv, *ivprv;
72 struct req_iterator iter;
73 struct scatterlist *sg;
74 unsigned int segments;
75
76 ivprv = NULL;
77 sg = NULL;
78 segments = 0;
79
80 rq_for_each_integrity_segment(iv, rq, iter) {
81
82 if (ivprv) {
83 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
84 goto new_segment;
85
86 sg->length += iv->bv_len;
87 } else {
88new_segment:
89 if (!sg)
90 sg = sglist;
91 else {
92 sg->page_link &= ~0x02;
93 sg = sg_next(sg);
94 }
95
96 sg_set_page(sg, iv->bv_page, iv->bv_len, iv->bv_offset);
97 segments++;
98 }
99
100 ivprv = iv;
101 }
102
103 if (sg)
104 sg_mark_end(sg);
105
106 return segments;
107}
108EXPORT_SYMBOL(blk_rq_map_integrity_sg);
109
110/**
111 * blk_integrity_compare - Compare integrity profile of two block devices
112 * @b1: Device to compare
113 * @b2: Device to compare
114 *
115 * Description: Meta-devices like DM and MD need to verify that all
116 * sub-devices use the same integrity format before advertising to
117 * upper layers that they can send/receive integrity metadata. This
118 * function can be used to check whether two block devices have
119 * compatible integrity formats.
120 */
121int blk_integrity_compare(struct block_device *bd1, struct block_device *bd2)
122{
123 struct blk_integrity *b1 = bd1->bd_disk->integrity;
124 struct blk_integrity *b2 = bd2->bd_disk->integrity;
125
126 BUG_ON(bd1->bd_disk == NULL);
127 BUG_ON(bd2->bd_disk == NULL);
128
129 if (!b1 || !b2)
130 return 0;
131
132 if (b1->sector_size != b2->sector_size) {
133 printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__,
134 bd1->bd_disk->disk_name, bd2->bd_disk->disk_name,
135 b1->sector_size, b2->sector_size);
136 return -1;
137 }
138
139 if (b1->tuple_size != b2->tuple_size) {
140 printk(KERN_ERR "%s: %s/%s tuple sz %u != %u\n", __func__,
141 bd1->bd_disk->disk_name, bd2->bd_disk->disk_name,
142 b1->tuple_size, b2->tuple_size);
143 return -1;
144 }
145
146 if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
147 printk(KERN_ERR "%s: %s/%s tag sz %u != %u\n", __func__,
148 bd1->bd_disk->disk_name, bd2->bd_disk->disk_name,
149 b1->tag_size, b2->tag_size);
150 return -1;
151 }
152
153 if (strcmp(b1->name, b2->name)) {
154 printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__,
155 bd1->bd_disk->disk_name, bd2->bd_disk->disk_name,
156 b1->name, b2->name);
157 return -1;
158 }
159
160 return 0;
161}
162EXPORT_SYMBOL(blk_integrity_compare);
163
164struct integrity_sysfs_entry {
165 struct attribute attr;
166 ssize_t (*show)(struct blk_integrity *, char *);
167 ssize_t (*store)(struct blk_integrity *, const char *, size_t);
168};
169
170static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
171 char *page)
172{
173 struct blk_integrity *bi =
174 container_of(kobj, struct blk_integrity, kobj);
175 struct integrity_sysfs_entry *entry =
176 container_of(attr, struct integrity_sysfs_entry, attr);
177
178 return entry->show(bi, page);
179}
180
181static ssize_t integrity_attr_store(struct kobject *kobj, struct attribute *attr,
182 const char *page, size_t count)
183{
184 struct blk_integrity *bi =
185 container_of(kobj, struct blk_integrity, kobj);
186 struct integrity_sysfs_entry *entry =
187 container_of(attr, struct integrity_sysfs_entry, attr);
188 ssize_t ret = 0;
189
190 if (entry->store)
191 ret = entry->store(bi, page, count);
192
193 return ret;
194}
195
196static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
197{
198 if (bi != NULL && bi->name != NULL)
199 return sprintf(page, "%s\n", bi->name);
200 else
201 return sprintf(page, "none\n");
202}
203
204static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
205{
206 if (bi != NULL)
207 return sprintf(page, "%u\n", bi->tag_size);
208 else
209 return sprintf(page, "0\n");
210}
211
212static ssize_t integrity_read_store(struct blk_integrity *bi,
213 const char *page, size_t count)
214{
215 char *p = (char *) page;
216 unsigned long val = simple_strtoul(p, &p, 10);
217
218 if (val)
219 set_bit(INTEGRITY_FLAG_READ, &bi->flags);
220 else
221 clear_bit(INTEGRITY_FLAG_READ, &bi->flags);
222
223 return count;
224}
225
226static ssize_t integrity_read_show(struct blk_integrity *bi, char *page)
227{
228 return sprintf(page, "%d\n",
229 test_bit(INTEGRITY_FLAG_READ, &bi->flags) ? 1 : 0);
230}
231
232static ssize_t integrity_write_store(struct blk_integrity *bi,
233 const char *page, size_t count)
234{
235 char *p = (char *) page;
236 unsigned long val = simple_strtoul(p, &p, 10);
237
238 if (val)
239 set_bit(INTEGRITY_FLAG_WRITE, &bi->flags);
240 else
241 clear_bit(INTEGRITY_FLAG_WRITE, &bi->flags);
242
243 return count;
244}
245
246static ssize_t integrity_write_show(struct blk_integrity *bi, char *page)
247{
248 return sprintf(page, "%d\n",
249 test_bit(INTEGRITY_FLAG_WRITE, &bi->flags) ? 1 : 0);
250}
251
252static struct integrity_sysfs_entry integrity_format_entry = {
253 .attr = { .name = "format", .mode = S_IRUGO },
254 .show = integrity_format_show,
255};
256
257static struct integrity_sysfs_entry integrity_tag_size_entry = {
258 .attr = { .name = "tag_size", .mode = S_IRUGO },
259 .show = integrity_tag_size_show,
260};
261
262static struct integrity_sysfs_entry integrity_read_entry = {
263 .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR },
264 .show = integrity_read_show,
265 .store = integrity_read_store,
266};
267
268static struct integrity_sysfs_entry integrity_write_entry = {
269 .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR },
270 .show = integrity_write_show,
271 .store = integrity_write_store,
272};
273
274static struct attribute *integrity_attrs[] = {
275 &integrity_format_entry.attr,
276 &integrity_tag_size_entry.attr,
277 &integrity_read_entry.attr,
278 &integrity_write_entry.attr,
279 NULL,
280};
281
282static struct sysfs_ops integrity_ops = {
283 .show = &integrity_attr_show,
284 .store = &integrity_attr_store,
285};
286
287static int __init blk_dev_integrity_init(void)
288{
289 integrity_cachep = kmem_cache_create("blkdev_integrity",
290 sizeof(struct blk_integrity),
291 0, SLAB_PANIC, NULL);
292 return 0;
293}
294subsys_initcall(blk_dev_integrity_init);
295
296static void blk_integrity_release(struct kobject *kobj)
297{
298 struct blk_integrity *bi =
299 container_of(kobj, struct blk_integrity, kobj);
300
301 kmem_cache_free(integrity_cachep, bi);
302}
303
304static struct kobj_type integrity_ktype = {
305 .default_attrs = integrity_attrs,
306 .sysfs_ops = &integrity_ops,
307 .release = blk_integrity_release,
308};
309
310/**
311 * blk_integrity_register - Register a gendisk as being integrity-capable
312 * @disk: struct gendisk pointer to make integrity-aware
313 * @template: integrity profile
314 *
315 * Description: When a device needs to advertise itself as being able
316 * to send/receive integrity metadata it must use this function to
317 * register the capability with the block layer. The template is a
318 * blk_integrity struct with values appropriate for the underlying
319 * hardware. See Documentation/block/data-integrity.txt.
320 */
321int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
322{
323 struct blk_integrity *bi;
324
325 BUG_ON(disk == NULL);
326 BUG_ON(template == NULL);
327
328 if (disk->integrity == NULL) {
329 bi = kmem_cache_alloc(integrity_cachep, GFP_KERNEL | __GFP_ZERO);
330 if (!bi)
331 return -1;
332
333 if (kobject_init_and_add(&bi->kobj, &integrity_ktype,
334 &disk->dev.kobj, "%s", "integrity")) {
335 kmem_cache_free(integrity_cachep, bi);
336 return -1;
337 }
338
339 kobject_uevent(&bi->kobj, KOBJ_ADD);
340
341 set_bit(INTEGRITY_FLAG_READ, &bi->flags);
342 set_bit(INTEGRITY_FLAG_WRITE, &bi->flags);
343 bi->sector_size = disk->queue->hardsect_size;
344 disk->integrity = bi;
345 } else
346 bi = disk->integrity;
347
348 /* Use the provided profile as template */
349 bi->name = template->name;
350 bi->generate_fn = template->generate_fn;
351 bi->verify_fn = template->verify_fn;
352 bi->tuple_size = template->tuple_size;
353 bi->set_tag_fn = template->set_tag_fn;
354 bi->get_tag_fn = template->get_tag_fn;
355 bi->tag_size = template->tag_size;
356
357 return 0;
358}
359EXPORT_SYMBOL(blk_integrity_register);
360
361/**
362 * blk_integrity_unregister - Remove block integrity profile
363 * @disk: disk whose integrity profile to deallocate
364 *
365 * Description: This function frees all memory used by the block
366 * integrity profile. To be called at device teardown.
367 */
368void blk_integrity_unregister(struct gendisk *disk)
369{
370 struct blk_integrity *bi;
371
372 if (!disk || !disk->integrity)
373 return;
374
375 bi = disk->integrity;
376
377 kobject_uevent(&bi->kobj, KOBJ_REMOVE);
378 kobject_del(&bi->kobj);
379 kobject_put(&disk->dev.kobj);
380 kmem_cache_free(integrity_cachep, bi);
381}
382EXPORT_SYMBOL(blk_integrity_unregister);