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 */
  27int 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 {
  45new_segment:
  46                        segments++;
  47                        seg_size = iv.bv_len;
  48                }
  49
  50                prev = 1;
  51                ivprv = iv;
  52        }
  53
  54        return segments;
  55}
  56EXPORT_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 */
  68int 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 {
  87new_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}
 108EXPORT_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 */
 121int 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}
 162EXPORT_SYMBOL(blk_integrity_compare);
 163
 164bool 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}
 186EXPORT_SYMBOL(blk_integrity_merge_rq);
 187
 188bool 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}
 215EXPORT_SYMBOL(blk_integrity_merge_bio);
 216
 217struct 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
 223static 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
 234static 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
 250static 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
 258static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
 259{
 260        return sprintf(page, "%u\n", bi->tag_size);
 261}
 262
 263static 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
 269static 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
 283static 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
 288static 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
 302static 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
 307static 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
 313static struct integrity_sysfs_entry integrity_format_entry = {
 314        .attr = { .name = "format", .mode = 0444 },
 315        .show = integrity_format_show,
 316};
 317
 318static struct integrity_sysfs_entry integrity_tag_size_entry = {
 319        .attr = { .name = "tag_size", .mode = 0444 },
 320        .show = integrity_tag_size_show,
 321};
 322
 323static struct integrity_sysfs_entry integrity_interval_entry = {
 324        .attr = { .name = "protection_interval_bytes", .mode = 0444 },
 325        .show = integrity_interval_show,
 326};
 327
 328static 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
 334static 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
 340static struct integrity_sysfs_entry integrity_device_entry = {
 341        .attr = { .name = "device_is_integrity_capable", .mode = 0444 },
 342        .show = integrity_device_show,
 343};
 344
 345static 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};
 354ATTRIBUTE_GROUPS(integrity);
 355
 356static const struct sysfs_ops integrity_ops = {
 357        .show   = &integrity_attr_show,
 358        .store  = &integrity_attr_store,
 359};
 360
 361static struct kobj_type integrity_ktype = {
 362        .default_groups = integrity_groups,
 363        .sysfs_ops      = &integrity_ops,
 364};
 365
 366static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
 367{
 368        return BLK_STS_OK;
 369}
 370
 371static 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.rst.
 387 */
 388void 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}
 402EXPORT_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 */
 411void 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}
 416EXPORT_SYMBOL(blk_integrity_unregister);
 417
 418void 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
 427void 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