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TOMOYO Linux Cross Reference
Linux/block/blk-integrity.c

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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, "\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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