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(q, &ivprv, &iv))
  53                                 goto new_segment;
  54                         if (seg_size + iv.bv_len > queue_max_segment_size(q))
  55                                 goto new_segment;
  56
  57                         seg_size += iv.bv_len;
  58                 } else {
  59 new_segment:
  60                         segments++;
  61                         seg_size = iv.bv_len;
  62                 }
  63
  64                 prev = 1;
  65                 ivprv = iv;
  66         }
  67
  68         return segments;
  69 }
  70 EXPORT_SYMBOL(blk_rq_count_integrity_sg);
  71
  72 /**
  73  * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
  74  * @q:          request queue
  75  * @bio:        bio with integrity metadata attached
  76  * @sglist:     target scatterlist
  77  *
  78  * Description: Map the integrity vectors in request into a
  79  * scatterlist.  The scatterlist must be big enough to hold all
  80  * elements.  I.e. sized using blk_rq_count_integrity_sg().
  81  */
  82 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
  83                             struct scatterlist *sglist)
  84 {
  85         struct bio_vec iv, ivprv = { NULL };
  86         struct scatterlist *sg = NULL;
  87         unsigned int segments = 0;
  88         struct bvec_iter iter;
  89         int prev = 0;
  90
  91         bio_for_each_integrity_vec(iv, bio, iter) {
  92
  93                 if (prev) {
  94                         if (!biovec_phys_mergeable(q, &ivprv, &iv))
  95                                 goto new_segment;
  96                         if (sg->length + iv.bv_len > queue_max_segment_size(q))
  97                                 goto new_segment;
  98
  99                         sg->length += iv.bv_len;
 100                 } else {
 101 new_segment:
 102                         if (!sg)
 103                                 sg = sglist;
 104                         else {
 105                                 sg_unmark_end(sg);
 106                                 sg = sg_next(sg);
 107                         }
 108
 109                         sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset);
 110                         segments++;
 111                 }
 112
 113                 prev = 1;
 114                 ivprv = iv;
 115         }
 116
 117         if (sg)
 118                 sg_mark_end(sg);
 119
 120         return segments;
 121 }
 122 EXPORT_SYMBOL(blk_rq_map_integrity_sg);
 123
 124 /**
 125  * blk_integrity_compare - Compare integrity profile of two disks
 126  * @gd1:        Disk to compare
 127  * @gd2:        Disk to compare
 128  *
 129  * Description: Meta-devices like DM and MD need to verify that all
 130  * sub-devices use the same integrity format before advertising to
 131  * upper layers that they can send/receive integrity metadata.  This
 132  * function can be used to check whether two gendisk devices have
 133  * compatible integrity formats.
 134  */
 135 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
 136 {
 137         struct blk_integrity *b1 = &gd1->queue->integrity;
 138         struct blk_integrity *b2 = &gd2->queue->integrity;
 139
 140         if (!b1->profile && !b2->profile)
 141                 return 0;
 142
 143         if (!b1->profile || !b2->profile)
 144                 return -1;
 145
 146         if (b1->interval_exp != b2->interval_exp) {
 147                 pr_err("%s: %s/%s protection interval %u != %u\n",
 148                        __func__, gd1->disk_name, gd2->disk_name,
 149                        1 << b1->interval_exp, 1 << b2->interval_exp);
 150                 return -1;
 151         }
 152
 153         if (b1->tuple_size != b2->tuple_size) {
 154                 pr_err("%s: %s/%s tuple sz %u != %u\n", __func__,
 155                        gd1->disk_name, gd2->disk_name,
 156                        b1->tuple_size, b2->tuple_size);
 157                 return -1;
 158         }
 159
 160         if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
 161                 pr_err("%s: %s/%s tag sz %u != %u\n", __func__,
 162                        gd1->disk_name, gd2->disk_name,
 163                        b1->tag_size, b2->tag_size);
 164                 return -1;
 165         }
 166
 167         if (b1->profile != b2->profile) {
 168                 pr_err("%s: %s/%s type %s != %s\n", __func__,
 169                        gd1->disk_name, gd2->disk_name,
 170                        b1->profile->name, b2->profile->name);
 171                 return -1;
 172         }
 173
 174         return 0;
 175 }
 176 EXPORT_SYMBOL(blk_integrity_compare);
 177
 178 bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
 179                             struct request *next)
 180 {
 181         if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
 182                 return true;
 183
 184         if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
 185                 return false;
 186
 187         if (bio_integrity(req->bio)->bip_flags !=
 188             bio_integrity(next->bio)->bip_flags)
 189                 return false;
 190
 191         if (req->nr_integrity_segments + next->nr_integrity_segments >
 192             q->limits.max_integrity_segments)
 193                 return false;
 194
 195         if (integrity_req_gap_back_merge(req, next->bio))
 196                 return false;
 197
 198         return true;
 199 }
 200 EXPORT_SYMBOL(blk_integrity_merge_rq);
 201
 202 bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
 203                              struct bio *bio)
 204 {
 205         int nr_integrity_segs;
 206         struct bio *next = bio->bi_next;
 207
 208         if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
 209                 return true;
 210
 211         if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
 212                 return false;
 213
 214         if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
 215                 return false;
 216
 217         bio->bi_next = NULL;
 218         nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
 219         bio->bi_next = next;
 220
 221         if (req->nr_integrity_segments + nr_integrity_segs >
 222             q->limits.max_integrity_segments)
 223                 return false;
 224
 225         req->nr_integrity_segments += nr_integrity_segs;
 226
 227         return true;
 228 }
 229 EXPORT_SYMBOL(blk_integrity_merge_bio);
 230
 231 struct integrity_sysfs_entry {
 232         struct attribute attr;
 233         ssize_t (*show)(struct blk_integrity *, char *);
 234         ssize_t (*store)(struct blk_integrity *, const char *, size_t);
 235 };
 236
 237 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
 238                                    char *page)
 239 {
 240         struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
 241         struct blk_integrity *bi = &disk->queue->integrity;
 242         struct integrity_sysfs_entry *entry =
 243                 container_of(attr, struct integrity_sysfs_entry, attr);
 244
 245         return entry->show(bi, page);
 246 }
 247
 248 static ssize_t integrity_attr_store(struct kobject *kobj,
 249                                     struct attribute *attr, const char *page,
 250                                     size_t count)
 251 {
 252         struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
 253         struct blk_integrity *bi = &disk->queue->integrity;
 254         struct integrity_sysfs_entry *entry =
 255                 container_of(attr, struct integrity_sysfs_entry, attr);
 256         ssize_t ret = 0;
 257
 258         if (entry->store)
 259                 ret = entry->store(bi, page, count);
 260
 261         return ret;
 262 }
 263
 264 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
 265 {
 266         if (bi->profile && bi->profile->name)
 267                 return sprintf(page, "%s\n", bi->profile->name);
 268         else
 269                 return sprintf(page, "none\n");
 270 }
 271
 272 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
 273 {
 274         return sprintf(page, "%u\n", bi->tag_size);
 275 }
 276
 277 static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page)
 278 {
 279         return sprintf(page, "%u\n",
 280                        bi->interval_exp ? 1 << bi->interval_exp : 0);
 281 }
 282
 283 static ssize_t integrity_verify_store(struct blk_integrity *bi,
 284                                       const char *page, size_t count)
 285 {
 286         char *p = (char *) page;
 287         unsigned long val = simple_strtoul(p, &p, 10);
 288
 289         if (val)
 290                 bi->flags |= BLK_INTEGRITY_VERIFY;
 291         else
 292                 bi->flags &= ~BLK_INTEGRITY_VERIFY;
 293
 294         return count;
 295 }
 296
 297 static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page)
 298 {
 299         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0);
 300 }
 301
 302 static ssize_t integrity_generate_store(struct blk_integrity *bi,
 303                                         const char *page, size_t count)
 304 {
 305         char *p = (char *) page;
 306         unsigned long val = simple_strtoul(p, &p, 10);
 307
 308         if (val)
 309                 bi->flags |= BLK_INTEGRITY_GENERATE;
 310         else
 311                 bi->flags &= ~BLK_INTEGRITY_GENERATE;
 312
 313         return count;
 314 }
 315
 316 static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page)
 317 {
 318         return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0);
 319 }
 320
 321 static ssize_t integrity_device_show(struct blk_integrity *bi, char *page)
 322 {
 323         return sprintf(page, "%u\n",
 324                        (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0);
 325 }
 326
 327 static struct integrity_sysfs_entry integrity_format_entry = {
 328         .attr = { .name = "format", .mode = 0444 },
 329         .show = integrity_format_show,
 330 };
 331
 332 static struct integrity_sysfs_entry integrity_tag_size_entry = {
 333         .attr = { .name = "tag_size", .mode = 0444 },
 334         .show = integrity_tag_size_show,
 335 };
 336
 337 static struct integrity_sysfs_entry integrity_interval_entry = {
 338         .attr = { .name = "protection_interval_bytes", .mode = 0444 },
 339         .show = integrity_interval_show,
 340 };
 341
 342 static struct integrity_sysfs_entry integrity_verify_entry = {
 343         .attr = { .name = "read_verify", .mode = 0644 },
 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 = 0644 },
 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 = 0444 },
 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_interval_entry.attr,
 363         &integrity_verify_entry.attr,
 364         &integrity_generate_entry.attr,
 365         &integrity_device_entry.attr,
 366         NULL,
 367 };
 368
 369 static const struct sysfs_ops integrity_ops = {
 370         .show   = &integrity_attr_show,
 371         .store  = &integrity_attr_store,
 372 };
 373
 374 static struct kobj_type integrity_ktype = {
 375         .default_attrs  = integrity_attrs,
 376         .sysfs_ops      = &integrity_ops,
 377 };
 378
 379 static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
 380 {
 381         return BLK_STS_OK;
 382 }
 383
 384 static const struct blk_integrity_profile nop_profile = {
 385         .name = "nop",
 386         .generate_fn = blk_integrity_nop_fn,
 387         .verify_fn = blk_integrity_nop_fn,
 388 };
 389
 390 /**
 391  * blk_integrity_register - Register a gendisk as being integrity-capable
 392  * @disk:       struct gendisk pointer to make integrity-aware
 393  * @template:   block integrity profile to register
 394  *
 395  * Description: When a device needs to advertise itself as being able to
 396  * send/receive integrity metadata it must use this function to register
 397  * the capability with the block layer. The template is a blk_integrity
 398  * struct with values appropriate for the underlying hardware. See
 399  * Documentation/block/data-integrity.txt.
 400  */
 401 void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
 402 {
 403         struct blk_integrity *bi = &disk->queue->integrity;
 404
 405         bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
 406                 template->flags;
 407         bi->interval_exp = template->interval_exp ? :
 408                 ilog2(queue_logical_block_size(disk->queue));
 409         bi->profile = template->profile ? template->profile : &nop_profile;
 410         bi->tuple_size = template->tuple_size;
 411         bi->tag_size = template->tag_size;
 412
 413         disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
 414 }
 415 EXPORT_SYMBOL(blk_integrity_register);
 416
 417 /**
 418  * blk_integrity_unregister - Unregister block integrity profile
 419  * @disk:       disk whose integrity profile to unregister
 420  *
 421  * Description: This function unregisters the integrity capability from
 422  * a block device.
 423  */
 424 void blk_integrity_unregister(struct gendisk *disk)
 425 {
 426         disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
 427         memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
 428 }
 429 EXPORT_SYMBOL(blk_integrity_unregister);
 430
 431 void blk_integrity_add(struct gendisk *disk)
 432 {
 433         if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
 434                                  &disk_to_dev(disk)->kobj, "%s", "integrity"))
 435                 return;
 436
 437         kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
 438 }
 439
 440 void blk_integrity_del(struct gendisk *disk)
 441 {
 442         kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
 443         kobject_del(&disk->integrity_kobj);
 444         kobject_put(&disk->integrity_kobj);
 445 }