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Linux/block/blk-integrity.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * blk-integrity.c - Block layer data integrity extensions
  4  *
  5  * Copyright (C) 2007, 2008 Oracle Corporation
  6  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
  7  */
  8 
  9 #include <linux/blkdev.h>
 10 #include <linux/backing-dev.h>
 11 #include <linux/mempool.h>
 12 #include <linux/bio.h>
 13 #include <linux/scatterlist.h>
 14 #include <linux/export.h>
 15 #include <linux/slab.h>
 16 
 17 #include "blk.h"
 18 
 19 /**
 20  * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
 21  * @q:          request queue
 22  * @bio:        bio with integrity metadata attached
 23  *
 24  * Description: Returns the number of elements required in a
 25  * scatterlist corresponding to the integrity metadata in a bio.
 26  */
 27 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
 28 {
 29         struct bio_vec iv, ivprv = { NULL };
 30         unsigned int segments = 0;
 31         unsigned int seg_size = 0;
 32         struct bvec_iter iter;
 33         int prev = 0;
 34 
 35         bio_for_each_integrity_vec(iv, bio, iter) {
 36 
 37                 if (prev) {
 38                         if (!biovec_phys_mergeable(q, &ivprv, &iv))
 39                                 goto new_segment;
 40                         if (seg_size + iv.bv_len > queue_max_segment_size(q))
 41                                 goto new_segment;
 42 
 43                         seg_size += iv.bv_len;
 44                 } else {
 45 new_segment:
 46                         segments++;
 47                         seg_size = iv.bv_len;
 48                 }
 49 
 50                 prev = 1;
 51                 ivprv = iv;
 52         }
 53 
 54         return segments;
 55 }
 56 EXPORT_SYMBOL(blk_rq_count_integrity_sg);
 57 
 58 /**
 59  * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
 60  * @q:          request queue
 61  * @bio:        bio with integrity metadata attached
 62  * @sglist:     target scatterlist
 63  *
 64  * Description: Map the integrity vectors in request into a
 65  * scatterlist.  The scatterlist must be big enough to hold all
 66  * elements.  I.e. sized using blk_rq_count_integrity_sg().
 67  */
 68 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
 69                             struct scatterlist *sglist)
 70 {
 71         struct bio_vec iv, ivprv = { NULL };
 72         struct scatterlist *sg = NULL;
 73         unsigned int segments = 0;
 74         struct bvec_iter iter;
 75         int prev = 0;
 76 
 77         bio_for_each_integrity_vec(iv, bio, iter) {
 78 
 79                 if (prev) {
 80                         if (!biovec_phys_mergeable(q, &ivprv, &iv))
 81                                 goto new_segment;
 82                         if (sg->length + iv.bv_len > queue_max_segment_size(q))
 83                                 goto new_segment;
 84 
 85                         sg->length += iv.bv_len;
 86                 } else {
 87 new_segment:
 88                         if (!sg)
 89                                 sg = sglist;
 90                         else {
 91                                 sg_unmark_end(sg);
 92                                 sg = sg_next(sg);
 93                         }
 94 
 95                         sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset);
 96                         segments++;
 97                 }
 98 
 99                 prev = 1;
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->queue->integrity;
124         struct blk_integrity *b2 = &gd2->queue->integrity;
125 
126         if (!b1->profile && !b2->profile)
127                 return 0;
128 
129         if (!b1->profile || !b2->profile)
130                 return -1;
131 
132         if (b1->interval_exp != b2->interval_exp) {
133                 pr_err("%s: %s/%s protection interval %u != %u\n",
134                        __func__, gd1->disk_name, gd2->disk_name,
135                        1 << b1->interval_exp, 1 << b2->interval_exp);
136                 return -1;
137         }
138 
139         if (b1->tuple_size != b2->tuple_size) {
140                 pr_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                 pr_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 (b1->profile != b2->profile) {
154                 pr_err("%s: %s/%s type %s != %s\n", __func__,
155                        gd1->disk_name, gd2->disk_name,
156                        b1->profile->name, b2->profile->name);
157                 return -1;
158         }
159 
160         return 0;
161 }
162 EXPORT_SYMBOL(blk_integrity_compare);
163 
164 bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
165                             struct request *next)
166 {
167         if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
168                 return true;
169 
170         if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
171                 return false;
172 
173         if (bio_integrity(req->bio)->bip_flags !=
174             bio_integrity(next->bio)->bip_flags)
175                 return false;
176 
177         if (req->nr_integrity_segments + next->nr_integrity_segments >
178             q->limits.max_integrity_segments)
179                 return false;
180 
181         if (integrity_req_gap_back_merge(req, next->bio))
182                 return false;
183 
184         return true;
185 }
186 EXPORT_SYMBOL(blk_integrity_merge_rq);
187 
188 bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
189                              struct bio *bio)
190 {
191         int nr_integrity_segs;
192         struct bio *next = bio->bi_next;
193 
194         if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
195                 return true;
196 
197         if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
198                 return false;
199 
200         if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
201                 return false;
202 
203         bio->bi_next = NULL;
204         nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
205         bio->bi_next = next;
206 
207         if (req->nr_integrity_segments + nr_integrity_segs >
208             q->limits.max_integrity_segments)
209                 return false;
210 
211         req->nr_integrity_segments += nr_integrity_segs;
212 
213         return true;
214 }
215 EXPORT_SYMBOL(blk_integrity_merge_bio);
216 
217 struct integrity_sysfs_entry {
218         struct attribute attr;
219         ssize_t (*show)(struct blk_integrity *, char *);
220         ssize_t (*store)(struct blk_integrity *, const char *, size_t);
221 };
222 
223 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
224                                    char *page)
225 {
226         struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
227         struct blk_integrity *bi = &disk->queue->integrity;
228         struct integrity_sysfs_entry *entry =
229                 container_of(attr, struct integrity_sysfs_entry, attr);
230 
231         return entry->show(bi, page);
232 }
233 
234 static ssize_t integrity_attr_store(struct kobject *kobj,
235                                     struct attribute *attr, const char *page,
236                                     size_t count)
237 {
238         struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
239         struct blk_integrity *bi = &disk->queue->integrity;
240         struct integrity_sysfs_entry *entry =
241                 container_of(attr, struct integrity_sysfs_entry, attr);
242         ssize_t ret = 0;
243 
244         if (entry->store)
245                 ret = entry->store(bi, page, count);
246 
247         return ret;
248 }
249 
250 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
251 {
252         if (bi->profile && bi->profile->name)
253                 return sprintf(page, "%s\n", bi->profile->name);
254         else
255                 return sprintf(page, "none\n");
256 }
257 
258 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
259 {
260         return sprintf(page, "%u\n", bi->tag_size);
261 }
262 
263 static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page)
264 {
265         return sprintf(page, "%u\n",
266                        bi->interval_exp ? 1 << bi->interval_exp : 0);
267 }
268 
269 static ssize_t integrity_verify_store(struct blk_integrity *bi,
270                                       const char *page, size_t count)
271 {
272         char *p = (char *) page;
273         unsigned long val = simple_strtoul(p, &p, 10);
274 
275         if (val)
276                 bi->flags |= BLK_INTEGRITY_VERIFY;
277         else
278                 bi->flags &= ~BLK_INTEGRITY_VERIFY;
279 
280         return count;
281 }
282 
283 static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page)
284 {
285         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0);
286 }
287 
288 static ssize_t integrity_generate_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_GENERATE;
296         else
297                 bi->flags &= ~BLK_INTEGRITY_GENERATE;
298 
299         return count;
300 }
301 
302 static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page)
303 {
304         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0);
305 }
306 
307 static ssize_t integrity_device_show(struct blk_integrity *bi, char *page)
308 {
309         return sprintf(page, "%u\n",
310                        (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0);
311 }
312 
313 static struct integrity_sysfs_entry integrity_format_entry = {
314         .attr = { .name = "format", .mode = 0444 },
315         .show = integrity_format_show,
316 };
317 
318 static struct integrity_sysfs_entry integrity_tag_size_entry = {
319         .attr = { .name = "tag_size", .mode = 0444 },
320         .show = integrity_tag_size_show,
321 };
322 
323 static struct integrity_sysfs_entry integrity_interval_entry = {
324         .attr = { .name = "protection_interval_bytes", .mode = 0444 },
325         .show = integrity_interval_show,
326 };
327 
328 static struct integrity_sysfs_entry integrity_verify_entry = {
329         .attr = { .name = "read_verify", .mode = 0644 },
330         .show = integrity_verify_show,
331         .store = integrity_verify_store,
332 };
333 
334 static struct integrity_sysfs_entry integrity_generate_entry = {
335         .attr = { .name = "write_generate", .mode = 0644 },
336         .show = integrity_generate_show,
337         .store = integrity_generate_store,
338 };
339 
340 static struct integrity_sysfs_entry integrity_device_entry = {
341         .attr = { .name = "device_is_integrity_capable", .mode = 0444 },
342         .show = integrity_device_show,
343 };
344 
345 static struct attribute *integrity_attrs[] = {
346         &integrity_format_entry.attr,
347         &integrity_tag_size_entry.attr,
348         &integrity_interval_entry.attr,
349         &integrity_verify_entry.attr,
350         &integrity_generate_entry.attr,
351         &integrity_device_entry.attr,
352         NULL,
353 };
354 ATTRIBUTE_GROUPS(integrity);
355 
356 static const struct sysfs_ops integrity_ops = {
357         .show   = &integrity_attr_show,
358         .store  = &integrity_attr_store,
359 };
360 
361 static struct kobj_type integrity_ktype = {
362         .default_groups = integrity_groups,
363         .sysfs_ops      = &integrity_ops,
364 };
365 
366 static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
367 {
368         return BLK_STS_OK;
369 }
370 
371 static const struct blk_integrity_profile nop_profile = {
372         .name = "nop",
373         .generate_fn = blk_integrity_nop_fn,
374         .verify_fn = blk_integrity_nop_fn,
375 };
376 
377 /**
378  * blk_integrity_register - Register a gendisk as being integrity-capable
379  * @disk:       struct gendisk pointer to make integrity-aware
380  * @template:   block integrity profile to register
381  *
382  * Description: When a device needs to advertise itself as being able to
383  * send/receive integrity metadata it must use this function to register
384  * the capability with the block layer. The template is a blk_integrity
385  * struct with values appropriate for the underlying hardware. See
386  * Documentation/block/data-integrity.txt.
387  */
388 void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
389 {
390         struct blk_integrity *bi = &disk->queue->integrity;
391 
392         bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
393                 template->flags;
394         bi->interval_exp = template->interval_exp ? :
395                 ilog2(queue_logical_block_size(disk->queue));
396         bi->profile = template->profile ? template->profile : &nop_profile;
397         bi->tuple_size = template->tuple_size;
398         bi->tag_size = template->tag_size;
399 
400         disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
401 }
402 EXPORT_SYMBOL(blk_integrity_register);
403 
404 /**
405  * blk_integrity_unregister - Unregister block integrity profile
406  * @disk:       disk whose integrity profile to unregister
407  *
408  * Description: This function unregisters the integrity capability from
409  * a block device.
410  */
411 void blk_integrity_unregister(struct gendisk *disk)
412 {
413         disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
414         memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
415 }
416 EXPORT_SYMBOL(blk_integrity_unregister);
417 
418 void blk_integrity_add(struct gendisk *disk)
419 {
420         if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
421                                  &disk_to_dev(disk)->kobj, "%s", "integrity"))
422                 return;
423 
424         kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
425 }
426 
427 void blk_integrity_del(struct gendisk *disk)
428 {
429         kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
430         kobject_del(&disk->integrity_kobj);
431         kobject_put(&disk->integrity_kobj);
432 }
433 

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