Driver core: Constify struct sysfs_ops in struct kobj_type
[linux-2.6.git] / block / blk-integrity.c
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
30 static 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  */
39 int 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 }
58 EXPORT_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  */
69 int 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 {
88 new_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 }
108 EXPORT_SYMBOL(blk_rq_map_integrity_sg);
109
110 /**
111  * blk_integrity_compare - Compare integrity profile of two disks
112  * @gd1:        Disk to compare
113  * @gd2:        Disk 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 gendisk devices have
119  * compatible integrity formats.
120  */
121 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
122 {
123         struct blk_integrity *b1 = gd1->integrity;
124         struct blk_integrity *b2 = gd2->integrity;
125
126         if (!b1 && !b2)
127                 return 0;
128
129         if (!b1 || !b2)
130                 return -1;
131
132         if (b1->sector_size != b2->sector_size) {
133                 printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__,
134                        gd1->disk_name, gd2->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                        gd1->disk_name, gd2->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                        gd1->disk_name, gd2->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                        gd1->disk_name, gd2->disk_name,
156                        b1->name, b2->name);
157                 return -1;
158         }
159
160         return 0;
161 }
162 EXPORT_SYMBOL(blk_integrity_compare);
163
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);
168 };
169
170 static 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
181 static ssize_t integrity_attr_store(struct kobject *kobj,
182                                     struct attribute *attr, const char *page,
183                                     size_t count)
184 {
185         struct blk_integrity *bi =
186                 container_of(kobj, struct blk_integrity, kobj);
187         struct integrity_sysfs_entry *entry =
188                 container_of(attr, struct integrity_sysfs_entry, attr);
189         ssize_t ret = 0;
190
191         if (entry->store)
192                 ret = entry->store(bi, page, count);
193
194         return ret;
195 }
196
197 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
198 {
199         if (bi != NULL && bi->name != NULL)
200                 return sprintf(page, "%s\n", bi->name);
201         else
202                 return sprintf(page, "none\n");
203 }
204
205 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
206 {
207         if (bi != NULL)
208                 return sprintf(page, "%u\n", bi->tag_size);
209         else
210                 return sprintf(page, "0\n");
211 }
212
213 static ssize_t integrity_read_store(struct blk_integrity *bi,
214                                     const char *page, size_t count)
215 {
216         char *p = (char *) page;
217         unsigned long val = simple_strtoul(p, &p, 10);
218
219         if (val)
220                 bi->flags |= INTEGRITY_FLAG_READ;
221         else
222                 bi->flags &= ~INTEGRITY_FLAG_READ;
223
224         return count;
225 }
226
227 static ssize_t integrity_read_show(struct blk_integrity *bi, char *page)
228 {
229         return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_READ) != 0);
230 }
231
232 static 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                 bi->flags |= INTEGRITY_FLAG_WRITE;
240         else
241                 bi->flags &= ~INTEGRITY_FLAG_WRITE;
242
243         return count;
244 }
245
246 static ssize_t integrity_write_show(struct blk_integrity *bi, char *page)
247 {
248         return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_WRITE) != 0);
249 }
250
251 static struct integrity_sysfs_entry integrity_format_entry = {
252         .attr = { .name = "format", .mode = S_IRUGO },
253         .show = integrity_format_show,
254 };
255
256 static struct integrity_sysfs_entry integrity_tag_size_entry = {
257         .attr = { .name = "tag_size", .mode = S_IRUGO },
258         .show = integrity_tag_size_show,
259 };
260
261 static struct integrity_sysfs_entry integrity_read_entry = {
262         .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR },
263         .show = integrity_read_show,
264         .store = integrity_read_store,
265 };
266
267 static struct integrity_sysfs_entry integrity_write_entry = {
268         .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR },
269         .show = integrity_write_show,
270         .store = integrity_write_store,
271 };
272
273 static struct attribute *integrity_attrs[] = {
274         &integrity_format_entry.attr,
275         &integrity_tag_size_entry.attr,
276         &integrity_read_entry.attr,
277         &integrity_write_entry.attr,
278         NULL,
279 };
280
281 static const struct sysfs_ops integrity_ops = {
282         .show   = &integrity_attr_show,
283         .store  = &integrity_attr_store,
284 };
285
286 static int __init blk_dev_integrity_init(void)
287 {
288         integrity_cachep = kmem_cache_create("blkdev_integrity",
289                                              sizeof(struct blk_integrity),
290                                              0, SLAB_PANIC, NULL);
291         return 0;
292 }
293 subsys_initcall(blk_dev_integrity_init);
294
295 static void blk_integrity_release(struct kobject *kobj)
296 {
297         struct blk_integrity *bi =
298                 container_of(kobj, struct blk_integrity, kobj);
299
300         kmem_cache_free(integrity_cachep, bi);
301 }
302
303 static struct kobj_type integrity_ktype = {
304         .default_attrs  = integrity_attrs,
305         .sysfs_ops      = &integrity_ops,
306         .release        = blk_integrity_release,
307 };
308
309 /**
310  * blk_integrity_register - Register a gendisk as being integrity-capable
311  * @disk:       struct gendisk pointer to make integrity-aware
312  * @template:   optional integrity profile to register
313  *
314  * Description: When a device needs to advertise itself as being able
315  * to send/receive integrity metadata it must use this function to
316  * register the capability with the block layer.  The template is a
317  * blk_integrity struct with values appropriate for the underlying
318  * hardware.  If template is NULL the new profile is allocated but
319  * not filled out. See Documentation/block/data-integrity.txt.
320  */
321 int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
322 {
323         struct blk_integrity *bi;
324
325         BUG_ON(disk == NULL);
326
327         if (disk->integrity == NULL) {
328                 bi = kmem_cache_alloc(integrity_cachep,
329                                       GFP_KERNEL | __GFP_ZERO);
330                 if (!bi)
331                         return -1;
332
333                 if (kobject_init_and_add(&bi->kobj, &integrity_ktype,
334                                          &disk_to_dev(disk)->kobj,
335                                          "%s", "integrity")) {
336                         kmem_cache_free(integrity_cachep, bi);
337                         return -1;
338                 }
339
340                 kobject_uevent(&bi->kobj, KOBJ_ADD);
341
342                 bi->flags |= INTEGRITY_FLAG_READ | INTEGRITY_FLAG_WRITE;
343                 bi->sector_size = queue_logical_block_size(disk->queue);
344                 disk->integrity = bi;
345         } else
346                 bi = disk->integrity;
347
348         /* Use the provided profile as template */
349         if (template != NULL) {
350                 bi->name = template->name;
351                 bi->generate_fn = template->generate_fn;
352                 bi->verify_fn = template->verify_fn;
353                 bi->tuple_size = template->tuple_size;
354                 bi->set_tag_fn = template->set_tag_fn;
355                 bi->get_tag_fn = template->get_tag_fn;
356                 bi->tag_size = template->tag_size;
357         } else
358                 bi->name = "unsupported";
359
360         return 0;
361 }
362 EXPORT_SYMBOL(blk_integrity_register);
363
364 /**
365  * blk_integrity_unregister - Remove block integrity profile
366  * @disk:       disk whose integrity profile to deallocate
367  *
368  * Description: This function frees all memory used by the block
369  * integrity profile.  To be called at device teardown.
370  */
371 void blk_integrity_unregister(struct gendisk *disk)
372 {
373         struct blk_integrity *bi;
374
375         if (!disk || !disk->integrity)
376                 return;
377
378         bi = disk->integrity;
379
380         kobject_uevent(&bi->kobj, KOBJ_REMOVE);
381         kobject_del(&bi->kobj);
382         kobject_put(&bi->kobj);
383         kmem_cache_free(integrity_cachep, bi);
384         disk->integrity = NULL;
385 }
386 EXPORT_SYMBOL(blk_integrity_unregister);