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
  13 static struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
  14                 gfp_t gfp)
  15 {
  16         struct bio *new = bio_alloc(gfp, nr_pages);
  17
  18         if (bio) {
  19                 bio_chain(bio, new);
  20                 submit_bio(bio);
  21         }
  22
  23         return new;
  24 }
  25
  26 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  27                 sector_t nr_sects, gfp_t gfp_mask, int flags,
  28                 struct bio **biop)
  29 {
  30         struct request_queue *q = bdev_get_queue(bdev);
  31         struct bio *bio = *biop;
  32         unsigned int granularity;
  33         unsigned int op;
  34         int alignment;
  35         sector_t bs_mask;
  36
  37         if (!q)
  38                 return -ENXIO;
  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         /* Zero-sector (unknown) and one-sector granularities are the same.  */
  55         granularity = max(q->limits.discard_granularity >> 9, 1U);
  56         alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
  57
  58         while (nr_sects) {
  59                 unsigned int req_sects;
  60                 sector_t end_sect, tmp;
  61
  62                 /* Make sure bi_size doesn't overflow */
  63                 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
  64
  65                 /**
  66                  * If splitting a request, and the next starting sector would be
  67                  * misaligned, stop the discard at the previous aligned sector.
  68                  */
  69                 end_sect = sector + req_sects;
  70                 tmp = end_sect;
  71                 if (req_sects < nr_sects &&
  72                     sector_div(tmp, granularity) != alignment) {
  73                         end_sect = end_sect - alignment;
  74                         sector_div(end_sect, granularity);
  75                         end_sect = end_sect * granularity + alignment;
  76                         req_sects = end_sect - sector;
  77                 }
  78
  79                 bio = next_bio(bio, 0, gfp_mask);
  80                 bio->bi_iter.bi_sector = sector;
  81                 bio_set_dev(bio, bdev);
  82                 bio_set_op_attrs(bio, op, 0);
  83
  84                 bio->bi_iter.bi_size = req_sects << 9;
  85                 nr_sects -= req_sects;
  86                 sector = end_sect;
  87
  88                 /*
  89                  * We can loop for a long time in here, if someone does
  90                  * full device discards (like mkfs). Be nice and allow
  91                  * us to schedule out to avoid softlocking if preempt
  92                  * is disabled.
  93                  */
  94                 cond_resched();
  95         }
  96
  97         *biop = bio;
  98         return 0;
  99 }
 100 EXPORT_SYMBOL(__blkdev_issue_discard);
 101
 102 /**
 103  * blkdev_issue_discard - queue a discard
 104  * @bdev:       blockdev to issue discard for
 105  * @sector:     start sector
 106  * @nr_sects:   number of sectors to discard
 107  * @gfp_mask:   memory allocation flags (for bio_alloc)
 108  * @flags:      BLKDEV_DISCARD_* flags to control behaviour
 109  *
 110  * Description:
 111  *    Issue a discard request for the sectors in question.
 112  */
 113 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 114                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
 115 {
 116         struct bio *bio = NULL;
 117         struct blk_plug plug;
 118         int ret;
 119
 120         blk_start_plug(&plug);
 121         ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
 122                         &bio);
 123         if (!ret && bio) {
 124                 ret = submit_bio_wait(bio);
 125                 if (ret == -EOPNOTSUPP)
 126                         ret = 0;
 127                 bio_put(bio);
 128         }
 129         blk_finish_plug(&plug);
 130
 131         return ret;
 132 }
 133 EXPORT_SYMBOL(blkdev_issue_discard);
 134
 135 /**
 136  * __blkdev_issue_write_same - generate number of bios with same page
 137  * @bdev:       target blockdev
 138  * @sector:     start sector
 139  * @nr_sects:   number of sectors to write
 140  * @gfp_mask:   memory allocation flags (for bio_alloc)
 141  * @page:       page containing data to write
 142  * @biop:       pointer to anchor bio
 143  *
 144  * Description:
 145  *  Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
 146  */
 147 static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 148                 sector_t nr_sects, gfp_t gfp_mask, struct page *page,
 149                 struct bio **biop)
 150 {
 151         struct request_queue *q = bdev_get_queue(bdev);
 152         unsigned int max_write_same_sectors;
 153         struct bio *bio = *biop;
 154         sector_t bs_mask;
 155
 156         if (!q)
 157                 return -ENXIO;
 158
 159         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 160         if ((sector | nr_sects) & bs_mask)
 161                 return -EINVAL;
 162
 163         if (!bdev_write_same(bdev))
 164                 return -EOPNOTSUPP;
 165
 166         /* Ensure that max_write_same_sectors doesn't overflow bi_size */
 167         max_write_same_sectors = UINT_MAX >> 9;
 168
 169         while (nr_sects) {
 170                 bio = next_bio(bio, 1, gfp_mask);
 171                 bio->bi_iter.bi_sector = sector;
 172                 bio_set_dev(bio, bdev);
 173                 bio->bi_vcnt = 1;
 174                 bio->bi_io_vec->bv_page = page;
 175                 bio->bi_io_vec->bv_offset = 0;
 176                 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
 177                 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
 178
 179                 if (nr_sects > max_write_same_sectors) {
 180                         bio->bi_iter.bi_size = max_write_same_sectors << 9;
 181                         nr_sects -= max_write_same_sectors;
 182                         sector += max_write_same_sectors;
 183                 } else {
 184                         bio->bi_iter.bi_size = nr_sects << 9;
 185                         nr_sects = 0;
 186                 }
 187                 cond_resched();
 188         }
 189
 190         *biop = bio;
 191         return 0;
 192 }
 193
 194 /**
 195  * blkdev_issue_write_same - queue a write same operation
 196  * @bdev:       target blockdev
 197  * @sector:     start sector
 198  * @nr_sects:   number of sectors to write
 199  * @gfp_mask:   memory allocation flags (for bio_alloc)
 200  * @page:       page containing data
 201  *
 202  * Description:
 203  *    Issue a write same request for the sectors in question.
 204  */
 205 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 206                                 sector_t nr_sects, gfp_t gfp_mask,
 207                                 struct page *page)
 208 {
 209         struct bio *bio = NULL;
 210         struct blk_plug plug;
 211         int ret;
 212
 213         blk_start_plug(&plug);
 214         ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
 215                         &bio);
 216         if (ret == 0 && bio) {
 217                 ret = submit_bio_wait(bio);
 218                 bio_put(bio);
 219         }
 220         blk_finish_plug(&plug);
 221         return ret;
 222 }
 223 EXPORT_SYMBOL(blkdev_issue_write_same);
 224
 225 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 226                 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 227                 struct bio **biop, unsigned flags)
 228 {
 229         struct bio *bio = *biop;
 230         unsigned int max_write_zeroes_sectors;
 231         struct request_queue *q = bdev_get_queue(bdev);
 232
 233         if (!q)
 234                 return -ENXIO;
 235
 236         /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
 237         max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
 238
 239         if (max_write_zeroes_sectors == 0)
 240                 return -EOPNOTSUPP;
 241
 242         while (nr_sects) {
 243                 bio = next_bio(bio, 0, gfp_mask);
 244                 bio->bi_iter.bi_sector = sector;
 245                 bio_set_dev(bio, bdev);
 246                 bio->bi_opf = REQ_OP_WRITE_ZEROES;
 247                 if (flags & BLKDEV_ZERO_NOUNMAP)
 248                         bio->bi_opf |= REQ_NOUNMAP;
 249
 250                 if (nr_sects > max_write_zeroes_sectors) {
 251                         bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
 252                         nr_sects -= max_write_zeroes_sectors;
 253                         sector += max_write_zeroes_sectors;
 254                 } else {
 255                         bio->bi_iter.bi_size = nr_sects << 9;
 256                         nr_sects = 0;
 257                 }
 258                 cond_resched();
 259         }
 260
 261         *biop = bio;
 262         return 0;
 263 }
 264
 265 /*
 266  * Convert a number of 512B sectors to a number of pages.
 267  * The result is limited to a number of pages that can fit into a BIO.
 268  * Also make sure that the result is always at least 1 (page) for the cases
 269  * where nr_sects is lower than the number of sectors in a page.
 270  */
 271 static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
 272 {
 273         sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
 274
 275         return min(pages, (sector_t)BIO_MAX_PAGES);
 276 }
 277
 278 static int __blkdev_issue_zero_pages(struct block_device *bdev,
 279                 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 280                 struct bio **biop)
 281 {
 282         struct request_queue *q = bdev_get_queue(bdev);
 283         struct bio *bio = *biop;
 284         int bi_size = 0;
 285         unsigned int sz;
 286
 287         if (!q)
 288                 return -ENXIO;
 289
 290         while (nr_sects != 0) {
 291                 bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
 292                                gfp_mask);
 293                 bio->bi_iter.bi_sector = sector;
 294                 bio_set_dev(bio, bdev);
 295                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 296
 297                 while (nr_sects != 0) {
 298                         sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
 299                         bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
 300                         nr_sects -= bi_size >> 9;
 301                         sector += bi_size >> 9;
 302                         if (bi_size < sz)
 303                                 break;
 304                 }
 305                 cond_resched();
 306         }
 307
 308         *biop = bio;
 309         return 0;
 310 }
 311
 312 /**
 313  * __blkdev_issue_zeroout - generate number of zero filed write bios
 314  * @bdev:       blockdev to issue
 315  * @sector:     start sector
 316  * @nr_sects:   number of sectors to write
 317  * @gfp_mask:   memory allocation flags (for bio_alloc)
 318  * @biop:       pointer to anchor bio
 319  * @flags:      controls detailed behavior
 320  *
 321  * Description:
 322  *  Zero-fill a block range, either using hardware offload or by explicitly
 323  *  writing zeroes to the device.
 324  *
 325  *  If a device is using logical block provisioning, the underlying space will
 326  *  not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
 327  *
 328  *  If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
 329  *  -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
 330  */
 331 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 332                 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
 333                 unsigned flags)
 334 {
 335         int ret;
 336         sector_t bs_mask;
 337
 338         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 339         if ((sector | nr_sects) & bs_mask)
 340                 return -EINVAL;
 341
 342         ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
 343                         biop, flags);
 344         if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
 345                 return ret;
 346
 347         return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
 348                                          biop);
 349 }
 350 EXPORT_SYMBOL(__blkdev_issue_zeroout);
 351
 352 /**
 353  * blkdev_issue_zeroout - zero-fill a block range
 354  * @bdev:       blockdev to write
 355  * @sector:     start sector
 356  * @nr_sects:   number of sectors to write
 357  * @gfp_mask:   memory allocation flags (for bio_alloc)
 358  * @flags:      controls detailed behavior
 359  *
 360  * Description:
 361  *  Zero-fill a block range, either using hardware offload or by explicitly
 362  *  writing zeroes to the device.  See __blkdev_issue_zeroout() for the
 363  *  valid values for %flags.
 364  */
 365 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 366                 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
 367 {
 368         int ret = 0;
 369         sector_t bs_mask;
 370         struct bio *bio;
 371         struct blk_plug plug;
 372         bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
 373
 374         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 375         if ((sector | nr_sects) & bs_mask)
 376                 return -EINVAL;
 377
 378 retry:
 379         bio = NULL;
 380         blk_start_plug(&plug);
 381         if (try_write_zeroes) {
 382                 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
 383                                                   gfp_mask, &bio, flags);
 384         } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
 385                 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
 386                                                 gfp_mask, &bio);
 387         } else {
 388                 /* No zeroing offload support */
 389                 ret = -EOPNOTSUPP;
 390         }
 391         if (ret == 0 && bio) {
 392                 ret = submit_bio_wait(bio);
 393                 bio_put(bio);
 394         }
 395         blk_finish_plug(&plug);
 396         if (ret && try_write_zeroes) {
 397                 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
 398                         try_write_zeroes = false;
 399                         goto retry;
 400                 }
 401                 if (!bdev_write_zeroes_sectors(bdev)) {
 402                         /*
 403                          * Zeroing offload support was indicated, but the
 404                          * device reported ILLEGAL REQUEST (for some devices
 405                          * there is no non-destructive way to verify whether
 406                          * WRITE ZEROES is actually supported).
 407                          */
 408                         ret = -EOPNOTSUPP;
 409                 }
 410         }
 411
 412         return ret;
 413 }
 414 EXPORT_SYMBOL(blkdev_issue_zeroout);