LXR linux/block/blk-lib.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Functions related to generic helpers functions
   4 */
   5#include <linux/kernel.h>
   6#include <linux/module.h>
   7#include <linux/bio.h>
   8#include <linux/blkdev.h>
   9#include <linux/scatterlist.h>
  10
  11#include "blk.h"
  12
  13struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
  14{
  15        struct bio *new = bio_alloc(gfp, nr_pages);
  16
  17        if (bio) {
  18                bio_chain(bio, new);
  19                submit_bio(bio);
  20        }
  21
  22        return new;
  23}
  24
  25int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  26                sector_t nr_sects, gfp_t gfp_mask, int flags,
  27                struct bio **biop)
  28{
  29        struct request_queue *q = bdev_get_queue(bdev);
  30        struct bio *bio = *biop;
  31        unsigned int op;
  32        sector_t bs_mask;
  33
  34        if (!q)
  35                return -ENXIO;
  36
  37        if (bdev_read_only(bdev))
  38                return -EPERM;
  39
  40        if (flags & BLKDEV_DISCARD_SECURE) {
  41                if (!blk_queue_secure_erase(q))
  42                        return -EOPNOTSUPP;
  43                op = REQ_OP_SECURE_ERASE;
  44        } else {
  45                if (!blk_queue_discard(q))
  46                        return -EOPNOTSUPP;
  47                op = REQ_OP_DISCARD;
  48        }
  49
  50        bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
  51        if ((sector | nr_sects) & bs_mask)
  52                return -EINVAL;
  53
  54        if (!nr_sects)
  55                return -EINVAL;
  56
  57        while (nr_sects) {
  58                sector_t req_sects = min_t(sector_t, nr_sects,
  59                                bio_allowed_max_sectors(q));
  60
  61                WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
  62
  63                bio = blk_next_bio(bio, 0, gfp_mask);
  64                bio->bi_iter.bi_sector = sector;
  65                bio_set_dev(bio, bdev);
  66                bio_set_op_attrs(bio, op, 0);
  67
  68                bio->bi_iter.bi_size = req_sects << 9;
  69                sector += req_sects;
  70                nr_sects -= req_sects;
  71
  72                /*
  73                 * We can loop for a long time in here, if someone does
  74                 * full device discards (like mkfs). Be nice and allow
  75                 * us to schedule out to avoid softlocking if preempt
  76                 * is disabled.
  77                 */
  78                cond_resched();
  79        }
  80
  81        *biop = bio;
  82        return 0;
  83}
  84EXPORT_SYMBOL(__blkdev_issue_discard);
  85
  86/**
  87 * blkdev_issue_discard - queue a discard
  88 * @bdev:       blockdev to issue discard for
  89 * @sector:     start sector
  90 * @nr_sects:   number of sectors to discard
  91 * @gfp_mask:   memory allocation flags (for bio_alloc)
  92 * @flags:      BLKDEV_DISCARD_* flags to control behaviour
  93 *
  94 * Description:
  95 *    Issue a discard request for the sectors in question.
  96 */
  97int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  98                sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
  99{
 100        struct bio *bio = NULL;
 101        struct blk_plug plug;
 102        int ret;
 103
 104        blk_start_plug(&plug);
 105        ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
 106                        &bio);
 107        if (!ret && bio) {
 108                ret = submit_bio_wait(bio);
 109                if (ret == -EOPNOTSUPP)
 110                        ret = 0;
 111                bio_put(bio);
 112        }
 113        blk_finish_plug(&plug);
 114
 115        return ret;
 116}
 117EXPORT_SYMBOL(blkdev_issue_discard);
 118
 119/**
 120 * __blkdev_issue_write_same - generate number of bios with same page
 121 * @bdev:       target blockdev
 122 * @sector:     start sector
 123 * @nr_sects:   number of sectors to write
 124 * @gfp_mask:   memory allocation flags (for bio_alloc)
 125 * @page:       page containing data to write
 126 * @biop:       pointer to anchor bio
 127 *
 128 * Description:
 129 *  Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
 130 */
 131static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 132                sector_t nr_sects, gfp_t gfp_mask, struct page *page,
 133                struct bio **biop)
 134{
 135        struct request_queue *q = bdev_get_queue(bdev);
 136        unsigned int max_write_same_sectors;
 137        struct bio *bio = *biop;
 138        sector_t bs_mask;
 139
 140        if (!q)
 141                return -ENXIO;
 142
 143        if (bdev_read_only(bdev))
 144                return -EPERM;
 145
 146        bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 147        if ((sector | nr_sects) & bs_mask)
 148                return -EINVAL;
 149
 150        if (!bdev_write_same(bdev))
 151                return -EOPNOTSUPP;
 152
 153        /* Ensure that max_write_same_sectors doesn't overflow bi_size */
 154        max_write_same_sectors = bio_allowed_max_sectors(q);
 155
 156        while (nr_sects) {
 157                bio = blk_next_bio(bio, 1, gfp_mask);
 158                bio->bi_iter.bi_sector = sector;
 159                bio_set_dev(bio, bdev);
 160                bio->bi_vcnt = 1;
 161                bio->bi_io_vec->bv_page = page;
 162                bio->bi_io_vec->bv_offset = 0;
 163                bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
 164                bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
 165
 166                if (nr_sects > max_write_same_sectors) {
 167                        bio->bi_iter.bi_size = max_write_same_sectors << 9;
 168                        nr_sects -= max_write_same_sectors;
 169                        sector += max_write_same_sectors;
 170                } else {
 171                        bio->bi_iter.bi_size = nr_sects << 9;
 172                        nr_sects = 0;
 173                }
 174                cond_resched();
 175        }
 176
 177        *biop = bio;
 178        return 0;
 179}
 180
 181/**
 182 * blkdev_issue_write_same - queue a write same operation
 183 * @bdev:       target blockdev
 184 * @sector:     start sector
 185 * @nr_sects:   number of sectors to write
 186 * @gfp_mask:   memory allocation flags (for bio_alloc)
 187 * @page:       page containing data
 188 *
 189 * Description:
 190 *    Issue a write same request for the sectors in question.
 191 */
 192int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 193                                sector_t nr_sects, gfp_t gfp_mask,
 194                                struct page *page)
 195{
 196        struct bio *bio = NULL;
 197        struct blk_plug plug;
 198        int ret;
 199
 200        blk_start_plug(&plug);
 201        ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
 202                        &bio);
 203        if (ret == 0 && bio) {
 204                ret = submit_bio_wait(bio);
 205                bio_put(bio);
 206        }
 207        blk_finish_plug(&plug);
 208        return ret;
 209}
 210EXPORT_SYMBOL(blkdev_issue_write_same);
 211
 212static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 213                sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 214                struct bio **biop, unsigned flags)
 215{
 216        struct bio *bio = *biop;
 217        unsigned int max_write_zeroes_sectors;
 218        struct request_queue *q = bdev_get_queue(bdev);
 219
 220        if (!q)
 221                return -ENXIO;
 222
 223        if (bdev_read_only(bdev))
 224                return -EPERM;
 225
 226        /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
 227        max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
 228
 229        if (max_write_zeroes_sectors == 0)
 230                return -EOPNOTSUPP;
 231
 232        while (nr_sects) {
 233                bio = blk_next_bio(bio, 0, gfp_mask);
 234                bio->bi_iter.bi_sector = sector;
 235                bio_set_dev(bio, bdev);
 236                bio->bi_opf = REQ_OP_WRITE_ZEROES;
 237                if (flags & BLKDEV_ZERO_NOUNMAP)
 238                        bio->bi_opf |= REQ_NOUNMAP;
 239
 240                if (nr_sects > max_write_zeroes_sectors) {
 241                        bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
 242                        nr_sects -= max_write_zeroes_sectors;
 243                        sector += max_write_zeroes_sectors;
 244                } else {
 245                        bio->bi_iter.bi_size = nr_sects << 9;
 246                        nr_sects = 0;
 247                }
 248                cond_resched();
 249        }
 250
 251        *biop = bio;
 252        return 0;
 253}
 254
 255/*
 256 * Convert a number of 512B sectors to a number of pages.
 257 * The result is limited to a number of pages that can fit into a BIO.
 258 * Also make sure that the result is always at least 1 (page) for the cases
 259 * where nr_sects is lower than the number of sectors in a page.
 260 */
 261static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
 262{
 263        sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
 264
 265        return min(pages, (sector_t)BIO_MAX_PAGES);
 266}
 267
 268static int __blkdev_issue_zero_pages(struct block_device *bdev,
 269                sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 270                struct bio **biop)
 271{
 272        struct request_queue *q = bdev_get_queue(bdev);
 273        struct bio *bio = *biop;
 274        int bi_size = 0;
 275        unsigned int sz;
 276
 277        if (!q)
 278                return -ENXIO;
 279
 280        if (bdev_read_only(bdev))
 281                return -EPERM;
 282
 283        while (nr_sects != 0) {
 284                bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
 285                                   gfp_mask);
 286                bio->bi_iter.bi_sector = sector;
 287                bio_set_dev(bio, bdev);
 288                bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 289
 290                while (nr_sects != 0) {
 291                        sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
 292                        bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
 293                        nr_sects -= bi_size >> 9;
 294                        sector += bi_size >> 9;
 295                        if (bi_size < sz)
 296                                break;
 297                }
 298                cond_resched();
 299        }
 300
 301        *biop = bio;
 302        return 0;
 303}
 304
 305/**
 306 * __blkdev_issue_zeroout - generate number of zero filed write bios
 307 * @bdev:       blockdev to issue
 308 * @sector:     start sector
 309 * @nr_sects:   number of sectors to write
 310 * @gfp_mask:   memory allocation flags (for bio_alloc)
 311 * @biop:       pointer to anchor bio
 312 * @flags:      controls detailed behavior
 313 *
 314 * Description:
 315 *  Zero-fill a block range, either using hardware offload or by explicitly
 316 *  writing zeroes to the device.
 317 *
 318 *  If a device is using logical block provisioning, the underlying space will
 319 *  not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
 320 *
 321 *  If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
 322 *  -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
 323 */
 324int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 325                sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
 326                unsigned flags)
 327{
 328        int ret;
 329        sector_t bs_mask;
 330
 331        bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 332        if ((sector | nr_sects) & bs_mask)
 333                return -EINVAL;
 334
 335        ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
 336                        biop, flags);
 337        if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
 338                return ret;
 339
 340        return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
 341                                         biop);
 342}
 343EXPORT_SYMBOL(__blkdev_issue_zeroout);
 344
 345/**
 346 * blkdev_issue_zeroout - zero-fill a block range
 347 * @bdev:       blockdev to write
 348 * @sector:     start sector
 349 * @nr_sects:   number of sectors to write
 350 * @gfp_mask:   memory allocation flags (for bio_alloc)
 351 * @flags:      controls detailed behavior
 352 *
 353 * Description:
 354 *  Zero-fill a block range, either using hardware offload or by explicitly
 355 *  writing zeroes to the device.  See __blkdev_issue_zeroout() for the
 356 *  valid values for %flags.
 357 */
 358int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 359                sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
 360{
 361        int ret = 0;
 362        sector_t bs_mask;
 363        struct bio *bio;
 364        struct blk_plug plug;
 365        bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
 366
 367        bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 368        if ((sector | nr_sects) & bs_mask)
 369                return -EINVAL;
 370
 371retry:
 372        bio = NULL;
 373        blk_start_plug(&plug);
 374        if (try_write_zeroes) {
 375                ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
 376                                                  gfp_mask, &bio, flags);
 377        } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
 378                ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
 379                                                gfp_mask, &bio);
 380        } else {
 381                /* No zeroing offload support */
 382                ret = -EOPNOTSUPP;
 383        }
 384        if (ret == 0 && bio) {
 385                ret = submit_bio_wait(bio);
 386                bio_put(bio);
 387        }
 388        blk_finish_plug(&plug);
 389        if (ret && try_write_zeroes) {
 390                if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
 391                        try_write_zeroes = false;
 392                        goto retry;
 393                }
 394                if (!bdev_write_zeroes_sectors(bdev)) {
 395                        /*
 396                         * Zeroing offload support was indicated, but the
 397                         * device reported ILLEGAL REQUEST (for some devices
 398                         * there is no non-destructive way to verify whether
 399                         * WRITE ZEROES is actually supported).
 400                         */
 401                        ret = -EOPNOTSUPP;
 402                }
 403        }
 404
 405        return ret;
 406}
 407EXPORT_SYMBOL(blkdev_issue_zeroout);
 408