block/blk-integrity.c

   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 void blk_integrity_nop_prepare(struct request *rq)
 372 {
 373 }
 374
 375 static void blk_integrity_nop_complete(struct request *rq,
 376                 unsigned int nr_bytes)
 377 {
 378 }
 379
 380 static const struct blk_integrity_profile nop_profile = {
 381         .name = "nop",
 382         .generate_fn = blk_integrity_nop_fn,
 383         .verify_fn = blk_integrity_nop_fn,
 384         .prepare_fn = blk_integrity_nop_prepare,
 385         .complete_fn = blk_integrity_nop_complete,
 386 };
 387
 388 /**
 389  * blk_integrity_register - Register a gendisk as being integrity-capable
 390  * @disk:       struct gendisk pointer to make integrity-aware
 391  * @template:   block integrity profile to register
 392  *
 393  * Description: When a device needs to advertise itself as being able to
 394  * send/receive integrity metadata it must use this function to register
 395  * the capability with the block layer. The template is a blk_integrity
 396  * struct with values appropriate for the underlying hardware. See
 397  * Documentation/block/data-integrity.rst.
 398  */
 399 void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
 400 {
 401         struct blk_integrity *bi = &disk->queue->integrity;
 402
 403         bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
 404                 template->flags;
 405         bi->interval_exp = template->interval_exp ? :
 406                 ilog2(queue_logical_block_size(disk->queue));
 407         bi->profile = template->profile ? template->profile : &nop_profile;
 408         bi->tuple_size = template->tuple_size;
 409         bi->tag_size = template->tag_size;
 410
 411         disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
 412 }
 413 EXPORT_SYMBOL(blk_integrity_register);
 414
 415 /**
 416  * blk_integrity_unregister - Unregister block integrity profile
 417  * @disk:       disk whose integrity profile to unregister
 418  *
 419  * Description: This function unregisters the integrity capability from
 420  * a block device.
 421  */
 422 void blk_integrity_unregister(struct gendisk *disk)
 423 {
 424         disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
 425         memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
 426 }
 427 EXPORT_SYMBOL(blk_integrity_unregister);
 428
 429 void blk_integrity_add(struct gendisk *disk)
 430 {
 431         if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
 432                                  &disk_to_dev(disk)->kobj, "%s", "integrity"))
 433                 return;
 434
 435         kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
 436 }
 437
 438 void blk_integrity_del(struct gendisk *disk)
 439 {
 440         kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
 441         kobject_del(&disk->integrity_kobj);
 442         kobject_put(&disk->integrity_kobj);
 443 }