block/blk-lib.c

   1 /*
   2  * Functions related to generic helpers functions
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/bio.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/scatterlist.h>
   9
  10 #include "blk.h"
  11
  12 struct bio_batch {
  13         atomic_t                done;
  14         unsigned long           flags;
  15         struct completion       *wait;
  16 };
  17
  18 static void bio_batch_end_io(struct bio *bio, int err)
  19 {
  20         struct bio_batch *bb = bio->bi_private;
  21
  22         if (err && (err != -EOPNOTSUPP))
  23                 clear_bit(BIO_UPTODATE, &bb->flags);
  24         if (atomic_dec_and_test(&bb->done))
  25                 complete(bb->wait);
  26         bio_put(bio);
  27 }
  28
  29 /**
  30  * blkdev_issue_discard - queue a discard
  31  * @bdev:       blockdev to issue discard for
  32  * @sector:     start sector
  33  * @nr_sects:   number of sectors to discard
  34  * @gfp_mask:   memory allocation flags (for bio_alloc)
  35  * @flags:      BLKDEV_IFL_* flags to control behaviour
  36  *
  37  * Description:
  38  *    Issue a discard request for the sectors in question.
  39  */
  40 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  41                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
  42 {
  43         DECLARE_COMPLETION_ONSTACK(wait);
  44         struct request_queue *q = bdev_get_queue(bdev);
  45         int type = REQ_WRITE | REQ_DISCARD;
  46         sector_t max_discard_sectors;
  47         sector_t granularity, alignment;
  48         struct bio_batch bb;
  49         struct bio *bio;
  50         int ret = 0;
  51
  52         if (!q)
  53                 return -ENXIO;
  54
  55         if (!blk_queue_discard(q))
  56                 return -EOPNOTSUPP;
  57
  58         /* Zero-sector (unknown) and one-sector granularities are the same.  */
  59         granularity = max(q->limits.discard_granularity >> 9, 1U);
  60         alignment = bdev_discard_alignment(bdev) >> 9;
  61         alignment = sector_div(alignment, granularity);
  62
  63         /*
  64          * Ensure that max_discard_sectors is of the proper
  65          * granularity, so that requests stay aligned after a split.
  66          */
  67         max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
  68         sector_div(max_discard_sectors, granularity);
  69         max_discard_sectors *= granularity;
  70         if (unlikely(!max_discard_sectors)) {
  71                 /* Avoid infinite loop below. Being cautious never hurts. */
  72                 return -EOPNOTSUPP;
  73         }
  74
  75         if (flags & BLKDEV_DISCARD_SECURE) {
  76                 if (!blk_queue_secdiscard(q))
  77                         return -EOPNOTSUPP;
  78                 type |= REQ_SECURE;
  79         }
  80
  81         atomic_set(&bb.done, 1);
  82         bb.flags = 1 << BIO_UPTODATE;
  83         bb.wait = &wait;
  84
  85         while (nr_sects) {
  86                 unsigned int req_sects;
  87                 sector_t end_sect, tmp;
  88
  89                 bio = bio_alloc(gfp_mask, 1);
  90                 if (!bio) {
  91                         ret = -ENOMEM;
  92                         break;
  93                 }
  94
  95                 req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
  96
  97                 /*
  98                  * If splitting a request, and the next starting sector would be
  99                  * misaligned, stop the discard at the previous aligned sector.
 100                  */
 101                 end_sect = sector + req_sects;
 102                 tmp = end_sect;
 103                 if (req_sects < nr_sects &&
 104                     sector_div(tmp, granularity) != alignment) {
 105                         end_sect = end_sect - alignment;
 106                         sector_div(end_sect, granularity);
 107                         end_sect = end_sect * granularity + alignment;
 108                         req_sects = end_sect - sector;
 109                 }
 110
 111                 bio->bi_sector = sector;
 112                 bio->bi_end_io = bio_batch_end_io;
 113                 bio->bi_bdev = bdev;
 114                 bio->bi_private = &bb;
 115
 116                 bio->bi_size = req_sects << 9;
 117                 nr_sects -= req_sects;
 118                 sector = end_sect;
 119
 120                 atomic_inc(&bb.done);
 121                 submit_bio(type, bio);
 122         }
 123
 124         /* Wait for bios in-flight */
 125         if (!atomic_dec_and_test(&bb.done))
 126                 wait_for_completion(&wait);
 127
 128         if (!test_bit(BIO_UPTODATE, &bb.flags))
 129                 ret = -EIO;
 130
 131         return ret;
 132 }
 133 EXPORT_SYMBOL(blkdev_issue_discard);
 134
 135 /**
 136  * blkdev_issue_write_same - queue a write same operation
 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  *
 143  * Description:
 144  *    Issue a write same request for the sectors in question.
 145  */
 146 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 147                             sector_t nr_sects, gfp_t gfp_mask,
 148                             struct page *page)
 149 {
 150         DECLARE_COMPLETION_ONSTACK(wait);
 151         struct request_queue *q = bdev_get_queue(bdev);
 152         unsigned int max_write_same_sectors;
 153         struct bio_batch bb;
 154         struct bio *bio;
 155         int ret = 0;
 156
 157         if (!q)
 158                 return -ENXIO;
 159
 160         max_write_same_sectors = q->limits.max_write_same_sectors;
 161
 162         if (max_write_same_sectors == 0)
 163                 return -EOPNOTSUPP;
 164
 165         atomic_set(&bb.done, 1);
 166         bb.flags = 1 << BIO_UPTODATE;
 167         bb.wait = &wait;
 168
 169         while (nr_sects) {
 170                 bio = bio_alloc(gfp_mask, 1);
 171                 if (!bio) {
 172                         ret = -ENOMEM;
 173                         break;
 174                 }
 175
 176                 bio->bi_sector = sector;
 177                 bio->bi_end_io = bio_batch_end_io;
 178                 bio->bi_bdev = bdev;
 179                 bio->bi_private = &bb;
 180                 bio->bi_vcnt = 1;
 181                 bio->bi_io_vec->bv_page = page;
 182                 bio->bi_io_vec->bv_offset = 0;
 183                 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
 184
 185                 if (nr_sects > max_write_same_sectors) {
 186                         bio->bi_size = max_write_same_sectors << 9;
 187                         nr_sects -= max_write_same_sectors;
 188                         sector += max_write_same_sectors;
 189                 } else {
 190                         bio->bi_size = nr_sects << 9;
 191                         nr_sects = 0;
 192                 }
 193
 194                 atomic_inc(&bb.done);
 195                 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
 196         }
 197
 198         /* Wait for bios in-flight */
 199         if (!atomic_dec_and_test(&bb.done))
 200                 wait_for_completion(&wait);
 201
 202         if (!test_bit(BIO_UPTODATE, &bb.flags))
 203                 ret = -ENOTSUPP;
 204
 205         return ret;
 206 }
 207 EXPORT_SYMBOL(blkdev_issue_write_same);
 208
 209 /**
 210  * blkdev_issue_zeroout - generate number of zero filed write bios
 211  * @bdev:       blockdev to issue
 212  * @sector:     start sector
 213  * @nr_sects:   number of sectors to write
 214  * @gfp_mask:   memory allocation flags (for bio_alloc)
 215  *
 216  * Description:
 217  *  Generate and issue number of bios with zerofiled pages.
 218  */
 219
 220 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 221                         sector_t nr_sects, gfp_t gfp_mask)
 222 {
 223         int ret;
 224         struct bio *bio;
 225         struct bio_batch bb;
 226         unsigned int sz;
 227         DECLARE_COMPLETION_ONSTACK(wait);
 228
 229         atomic_set(&bb.done, 1);
 230         bb.flags = 1 << BIO_UPTODATE;
 231         bb.wait = &wait;
 232
 233         ret = 0;
 234         while (nr_sects != 0) {
 235                 bio = bio_alloc(gfp_mask,
 236                                 min(nr_sects, (sector_t)BIO_MAX_PAGES));
 237                 if (!bio) {
 238                         ret = -ENOMEM;
 239                         break;
 240                 }
 241
 242                 bio->bi_sector = sector;
 243                 bio->bi_bdev   = bdev;
 244                 bio->bi_end_io = bio_batch_end_io;
 245                 bio->bi_private = &bb;
 246
 247                 while (nr_sects != 0) {
 248                         sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
 249                         ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
 250                         nr_sects -= ret >> 9;
 251                         sector += ret >> 9;
 252                         if (ret < (sz << 9))
 253                                 break;
 254                 }
 255                 ret = 0;
 256                 atomic_inc(&bb.done);
 257                 submit_bio(WRITE, bio);
 258         }
 259
 260         /* Wait for bios in-flight */
 261         if (!atomic_dec_and_test(&bb.done))
 262                 wait_for_completion(&wait);
 263
 264         if (!test_bit(BIO_UPTODATE, &bb.flags))
 265                 /* One of bios in the batch was completed with error.*/
 266                 ret = -EIO;
 267
 268         return ret;
 269 }
 270
 271 /**
 272  * blkdev_issue_zeroout - zero-fill a block range
 273  * @bdev:       blockdev to write
 274  * @sector:     start sector
 275  * @nr_sects:   number of sectors to write
 276  * @gfp_mask:   memory allocation flags (for bio_alloc)
 277  *
 278  * Description:
 279  *  Generate and issue number of bios with zerofiled pages.
 280  */
 281
 282 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 283                          sector_t nr_sects, gfp_t gfp_mask)
 284 {
 285         if (bdev_write_same(bdev)) {
 286                 unsigned char bdn[BDEVNAME_SIZE];
 287
 288                 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
 289                                              ZERO_PAGE(0)))
 290                         return 0;
 291
 292                 bdevname(bdev, bdn);
 293                 pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
 294         }
 295
 296         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
 297 }
 298 EXPORT_SYMBOL(blkdev_issue_zeroout);