2 * blk-integrity.c - Block layer data integrity extensions
4 * Copyright (C) 2007, 2008 Oracle Corporation
5 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
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.
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.
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,
23 #include <linux/blkdev.h>
24 #include <linux/mempool.h>
25 #include <linux/bio.h>
26 #include <linux/scatterlist.h>
30 static struct kmem_cache *integrity_cachep;
33 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
34 * @rq: request with integrity metadata attached
36 * Description: Returns the number of elements required in a
37 * scatterlist corresponding to the integrity metadata in a request.
39 int blk_rq_count_integrity_sg(struct request *rq)
41 struct bio_vec *iv, *ivprv;
42 struct req_iterator iter;
43 unsigned int segments;
48 rq_for_each_integrity_segment(iv, rq, iter) {
50 if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
58 EXPORT_SYMBOL(blk_rq_count_integrity_sg);
61 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
62 * @rq: request with integrity metadata attached
63 * @sglist: target scatterlist
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().
69 int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)
71 struct bio_vec *iv, *ivprv;
72 struct req_iterator iter;
73 struct scatterlist *sg;
74 unsigned int segments;
80 rq_for_each_integrity_segment(iv, rq, iter) {
83 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
86 sg->length += iv->bv_len;
92 sg->page_link &= ~0x02;
96 sg_set_page(sg, iv->bv_page, iv->bv_len, iv->bv_offset);
108 EXPORT_SYMBOL(blk_rq_map_integrity_sg);
111 * blk_integrity_compare - Compare integrity profile of two block devices
112 * @b1: Device to compare
113 * @b2: Device to compare
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.
121 int blk_integrity_compare(struct block_device *bd1, struct block_device *bd2)
123 struct blk_integrity *b1 = bd1->bd_disk->integrity;
124 struct blk_integrity *b2 = bd2->bd_disk->integrity;
126 BUG_ON(bd1->bd_disk == NULL);
127 BUG_ON(bd2->bd_disk == NULL);
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);
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);
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);
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,
162 EXPORT_SYMBOL(blk_integrity_compare);
164 struct 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);
170 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
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);
178 return entry->show(bi, page);
181 static ssize_t integrity_attr_store(struct kobject *kobj, struct attribute *attr,
182 const char *page, size_t count)
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);
191 ret = entry->store(bi, page, count);
196 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
198 if (bi != NULL && bi->name != NULL)
199 return sprintf(page, "%s\n", bi->name);
201 return sprintf(page, "none\n");
204 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
207 return sprintf(page, "%u\n", bi->tag_size);
209 return sprintf(page, "0\n");
212 static ssize_t integrity_read_store(struct blk_integrity *bi,
213 const char *page, size_t count)
215 char *p = (char *) page;
216 unsigned long val = simple_strtoul(p, &p, 10);
219 set_bit(INTEGRITY_FLAG_READ, &bi->flags);
221 clear_bit(INTEGRITY_FLAG_READ, &bi->flags);
226 static ssize_t integrity_read_show(struct blk_integrity *bi, char *page)
228 return sprintf(page, "%d\n",
229 test_bit(INTEGRITY_FLAG_READ, &bi->flags) ? 1 : 0);
232 static ssize_t integrity_write_store(struct blk_integrity *bi,
233 const char *page, size_t count)
235 char *p = (char *) page;
236 unsigned long val = simple_strtoul(p, &p, 10);
239 set_bit(INTEGRITY_FLAG_WRITE, &bi->flags);
241 clear_bit(INTEGRITY_FLAG_WRITE, &bi->flags);
246 static ssize_t integrity_write_show(struct blk_integrity *bi, char *page)
248 return sprintf(page, "%d\n",
249 test_bit(INTEGRITY_FLAG_WRITE, &bi->flags) ? 1 : 0);
252 static struct integrity_sysfs_entry integrity_format_entry = {
253 .attr = { .name = "format", .mode = S_IRUGO },
254 .show = integrity_format_show,
257 static struct integrity_sysfs_entry integrity_tag_size_entry = {
258 .attr = { .name = "tag_size", .mode = S_IRUGO },
259 .show = integrity_tag_size_show,
262 static 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,
268 static 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,
274 static 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,
282 static struct sysfs_ops integrity_ops = {
283 .show = &integrity_attr_show,
284 .store = &integrity_attr_store,
287 static int __init blk_dev_integrity_init(void)
289 integrity_cachep = kmem_cache_create("blkdev_integrity",
290 sizeof(struct blk_integrity),
291 0, SLAB_PANIC, NULL);
294 subsys_initcall(blk_dev_integrity_init);
296 static void blk_integrity_release(struct kobject *kobj)
298 struct blk_integrity *bi =
299 container_of(kobj, struct blk_integrity, kobj);
301 kmem_cache_free(integrity_cachep, bi);
304 static struct kobj_type integrity_ktype = {
305 .default_attrs = integrity_attrs,
306 .sysfs_ops = &integrity_ops,
307 .release = blk_integrity_release,
311 * blk_integrity_register - Register a gendisk as being integrity-capable
312 * @disk: struct gendisk pointer to make integrity-aware
313 * @template: integrity profile
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.
321 int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
323 struct blk_integrity *bi;
325 BUG_ON(disk == NULL);
326 BUG_ON(template == NULL);
328 if (disk->integrity == NULL) {
329 bi = kmem_cache_alloc(integrity_cachep, GFP_KERNEL | __GFP_ZERO);
333 if (kobject_init_and_add(&bi->kobj, &integrity_ktype,
334 &disk->dev.kobj, "%s", "integrity")) {
335 kmem_cache_free(integrity_cachep, bi);
339 kobject_uevent(&bi->kobj, KOBJ_ADD);
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;
346 bi = disk->integrity;
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;
359 EXPORT_SYMBOL(blk_integrity_register);
362 * blk_integrity_unregister - Remove block integrity profile
363 * @disk: disk whose integrity profile to deallocate
365 * Description: This function frees all memory used by the block
366 * integrity profile. To be called at device teardown.
368 void blk_integrity_unregister(struct gendisk *disk)
370 struct blk_integrity *bi;
372 if (!disk || !disk->integrity)
375 bi = disk->integrity;
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);
382 EXPORT_SYMBOL(blk_integrity_unregister);