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/backing-dev.h>
  25 #include <linux/mempool.h>
  26 #include <linux/bio.h>
  27 #include <linux/scatterlist.h>
  28 #include <linux/export.h>
  29 #include <linux/slab.h>
  30
  31 #include "blk.h"
  32
  33 /**
  34  * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
  35  * @q:          request queue
  36  * @bio:        bio with integrity metadata attached
  37  *
  38  * Description: Returns the number of elements required in a
  39  * scatterlist corresponding to the integrity metadata in a bio.
  40  */
  41 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
  42 {
  43         struct bio_vec iv, ivprv = { NULL };
  44         unsigned int segments = 0;
  45         unsigned int seg_size = 0;
  46         struct bvec_iter iter;
  47         int prev = 0;
  48
  49         bio_for_each_integrity_vec(iv, bio, iter) {
  50
  51                 if (prev) {
  52                         if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv))
  53                                 goto new_segment;
  54
  55                         if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv))
  56                                 goto new_segment;
  57
  58                         if (seg_size + iv.bv_len > queue_max_segment_size(q))
  59                                 goto new_segment;
  60
  61                         seg_size += iv.bv_len;
  62                 } else {
  63 new_segment:
  64                         segments++;
  65                         seg_size = iv.bv_len;
  66                 }
  67
  68                 prev = 1;
  69                 ivprv = iv;
  70         }
  71
  72         return segments;
  73 }
  74 EXPORT_SYMBOL(blk_rq_count_integrity_sg);
  75
  76 /**
  77  * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
  78  * @q:          request queue
  79  * @bio:        bio with integrity metadata attached
  80  * @sglist:     target scatterlist
  81  *
  82  * Description: Map the integrity vectors in request into a
  83  * scatterlist.  The scatterlist must be big enough to hold all
  84  * elements.  I.e. sized using blk_rq_count_integrity_sg().
  85  */
  86 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
  87                             struct scatterlist *sglist)
  88 {
  89         struct bio_vec iv, ivprv = { NULL };
  90         struct scatterlist *sg = NULL;
  91         unsigned int segments = 0;
  92         struct bvec_iter iter;
  93         int prev = 0;
  94
  95         bio_for_each_integrity_vec(iv, bio, iter) {
  96
  97                 if (prev) {
  98                         if (!BIOVEC_PHYS_MERGEABLE(&ivprv, &iv))
  99                                 goto new_segment;
 100
 101                         if (!BIOVEC_SEG_BOUNDARY(q, &ivprv, &iv))
 102                                 goto new_segment;
 103
 104                         if (sg->length + iv.bv_len > queue_max_segment_size(q))
 105                                 goto new_segment;
 106
 107                         sg->length += iv.bv_len;
 108                 } else {
 109 new_segment:
 110                         if (!sg)
 111                                 sg = sglist;
 112                         else {
 113                                 sg_unmark_end(sg);
 114                                 sg = sg_next(sg);
 115                         }
 116
 117                         sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset);
 118                         segments++;
 119                 }
 120
 121                 prev = 1;
 122                 ivprv = iv;
 123         }
 124
 125         if (sg)
 126                 sg_mark_end(sg);
 127
 128         return segments;
 129 }
 130 EXPORT_SYMBOL(blk_rq_map_integrity_sg);
 131
 132 /**
 133  * blk_integrity_compare - Compare integrity profile of two disks
 134  * @gd1:        Disk to compare
 135  * @gd2:        Disk to compare
 136  *
 137  * Description: Meta-devices like DM and MD need to verify that all
 138  * sub-devices use the same integrity format before advertising to
 139  * upper layers that they can send/receive integrity metadata.  This
 140  * function can be used to check whether two gendisk devices have
 141  * compatible integrity formats.
 142  */
 143 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
 144 {
 145         struct blk_integrity *b1 = &gd1->queue->integrity;
 146         struct blk_integrity *b2 = &gd2->queue->integrity;
 147
 148         if (!b1->profile && !b2->profile)
 149                 return 0;
 150
 151         if (!b1->profile || !b2->profile)
 152                 return -1;
 153
 154         if (b1->interval_exp != b2->interval_exp) {
 155                 pr_err("%s: %s/%s protection interval %u != %u\n",
 156                        __func__, gd1->disk_name, gd2->disk_name,
 157                        1 << b1->interval_exp, 1 << b2->interval_exp);
 158                 return -1;
 159         }
 160
 161         if (b1->tuple_size != b2->tuple_size) {
 162                 pr_err("%s: %s/%s tuple sz %u != %u\n", __func__,
 163                        gd1->disk_name, gd2->disk_name,
 164                        b1->tuple_size, b2->tuple_size);
 165                 return -1;
 166         }
 167
 168         if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
 169                 pr_err("%s: %s/%s tag sz %u != %u\n", __func__,
 170                        gd1->disk_name, gd2->disk_name,
 171                        b1->tag_size, b2->tag_size);
 172                 return -1;
 173         }
 174
 175         if (b1->profile != b2->profile) {
 176                 pr_err("%s: %s/%s type %s != %s\n", __func__,
 177                        gd1->disk_name, gd2->disk_name,
 178                        b1->profile->name, b2->profile->name);
 179                 return -1;
 180         }
 181
 182         return 0;
 183 }
 184 EXPORT_SYMBOL(blk_integrity_compare);
 185
 186 bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
 187                             struct request *next)
 188 {
 189         if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
 190                 return true;
 191
 192         if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
 193                 return false;
 194
 195         if (bio_integrity(req->bio)->bip_flags !=
 196             bio_integrity(next->bio)->bip_flags)
 197                 return false;
 198
 199         if (req->nr_integrity_segments + next->nr_integrity_segments >
 200             q->limits.max_integrity_segments)
 201                 return false;
 202
 203         if (integrity_req_gap_back_merge(req, next->bio))
 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 gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
 249         struct blk_integrity *bi = &disk->queue->integrity;
 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 gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
 261         struct blk_integrity *bi = &disk->queue->integrity;
 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->profile && bi->profile->name)
 275                 return sprintf(page, "%s\n", bi->profile->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         return sprintf(page, "%u\n", bi->tag_size);
 283 }
 284
 285 static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page)
 286 {
 287         return sprintf(page, "%u\n",
 288                        bi->interval_exp ? 1 << bi->interval_exp : 0);
 289 }
 290
 291 static ssize_t integrity_verify_store(struct blk_integrity *bi,
 292                                       const char *page, size_t count)
 293 {
 294         char *p = (char *) page;
 295         unsigned long val = simple_strtoul(p, &p, 10);
 296
 297         if (val)
 298                 bi->flags |= BLK_INTEGRITY_VERIFY;
 299         else
 300                 bi->flags &= ~BLK_INTEGRITY_VERIFY;
 301
 302         return count;
 303 }
 304
 305 static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page)
 306 {
 307         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0);
 308 }
 309
 310 static ssize_t integrity_generate_store(struct blk_integrity *bi,
 311                                         const char *page, size_t count)
 312 {
 313         char *p = (char *) page;
 314         unsigned long val = simple_strtoul(p, &p, 10);
 315
 316         if (val)
 317                 bi->flags |= BLK_INTEGRITY_GENERATE;
 318         else
 319                 bi->flags &= ~BLK_INTEGRITY_GENERATE;
 320
 321         return count;
 322 }
 323
 324 static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page)
 325 {
 326         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0);
 327 }
 328
 329 static ssize_t integrity_device_show(struct blk_integrity *bi, char *page)
 330 {
 331         return sprintf(page, "%u\n",
 332                        (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0);
 333 }
 334
 335 static struct integrity_sysfs_entry integrity_format_entry = {
 336         .attr = { .name = "format", .mode = S_IRUGO },
 337         .show = integrity_format_show,
 338 };
 339
 340 static struct integrity_sysfs_entry integrity_tag_size_entry = {
 341         .attr = { .name = "tag_size", .mode = S_IRUGO },
 342         .show = integrity_tag_size_show,
 343 };
 344
 345 static struct integrity_sysfs_entry integrity_interval_entry = {
 346         .attr = { .name = "protection_interval_bytes", .mode = S_IRUGO },
 347         .show = integrity_interval_show,
 348 };
 349
 350 static struct integrity_sysfs_entry integrity_verify_entry = {
 351         .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR },
 352         .show = integrity_verify_show,
 353         .store = integrity_verify_store,
 354 };
 355
 356 static struct integrity_sysfs_entry integrity_generate_entry = {
 357         .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR },
 358         .show = integrity_generate_show,
 359         .store = integrity_generate_store,
 360 };
 361
 362 static struct integrity_sysfs_entry integrity_device_entry = {
 363         .attr = { .name = "device_is_integrity_capable", .mode = S_IRUGO },
 364         .show = integrity_device_show,
 365 };
 366
 367 static struct attribute *integrity_attrs[] = {
 368         &integrity_format_entry.attr,
 369         &integrity_tag_size_entry.attr,
 370         &integrity_interval_entry.attr,
 371         &integrity_verify_entry.attr,
 372         &integrity_generate_entry.attr,
 373         &integrity_device_entry.attr,
 374         NULL,
 375 };
 376
 377 static const struct sysfs_ops integrity_ops = {
 378         .show   = &integrity_attr_show,
 379         .store  = &integrity_attr_store,
 380 };
 381
 382 static struct kobj_type integrity_ktype = {
 383         .default_attrs  = integrity_attrs,
 384         .sysfs_ops      = &integrity_ops,
 385 };
 386
 387 static int blk_integrity_nop_fn(struct blk_integrity_iter *iter)
 388 {
 389         return 0;
 390 }
 391
 392 static const struct blk_integrity_profile nop_profile = {
 393         .name = "nop",
 394         .generate_fn = blk_integrity_nop_fn,
 395         .verify_fn = blk_integrity_nop_fn,
 396 };
 397
 398 /**
 399  * blk_integrity_register - Register a gendisk as being integrity-capable
 400  * @disk:       struct gendisk pointer to make integrity-aware
 401  * @template:   block integrity profile to register
 402  *
 403  * Description: When a device needs to advertise itself as being able to
 404  * send/receive integrity metadata it must use this function to register
 405  * the capability with the block layer. The template is a blk_integrity
 406  * struct with values appropriate for the underlying hardware. See
 407  * Documentation/block/data-integrity.txt.
 408  */
 409 void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
 410 {
 411         struct blk_integrity *bi = &disk->queue->integrity;
 412
 413         bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
 414                 template->flags;
 415         bi->interval_exp = template->interval_exp ? :
 416                 ilog2(queue_logical_block_size(disk->queue));
 417         bi->profile = template->profile ? template->profile : &nop_profile;
 418         bi->tuple_size = template->tuple_size;
 419         bi->tag_size = template->tag_size;
 420
 421         disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
 422 }
 423 EXPORT_SYMBOL(blk_integrity_register);
 424
 425 /**
 426  * blk_integrity_unregister - Unregister block integrity profile
 427  * @disk:       disk whose integrity profile to unregister
 428  *
 429  * Description: This function unregisters the integrity capability from
 430  * a block device.
 431  */
 432 void blk_integrity_unregister(struct gendisk *disk)
 433 {
 434         disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
 435         memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
 436 }
 437 EXPORT_SYMBOL(blk_integrity_unregister);
 438
 439 void blk_integrity_add(struct gendisk *disk)
 440 {
 441         if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
 442                                  &disk_to_dev(disk)->kobj, "%s", "integrity"))
 443                 return;
 444
 445         kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
 446 }
 447
 448 void blk_integrity_del(struct gendisk *disk)
 449 {
 450         kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
 451         kobject_del(&disk->integrity_kobj);
 452         kobject_put(&disk->integrity_kobj);
 453 }