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         unsigned int max_discard_sectors;
  47         struct bio_batch bb;
  48         struct bio *bio;
  49         int ret = 0;
  50
  51         if (!q)
  52                 return -ENXIO;
  53
  54         if (!blk_queue_discard(q))
  55                 return -EOPNOTSUPP;
  56
  57         /*
  58          * Ensure that max_discard_sectors is of the proper
  59          * granularity
  60          */
  61         max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
  62         if (q->limits.discard_granularity) {
  63                 unsigned int disc_sects = q->limits.discard_granularity >> 9;
  64
  65                 max_discard_sectors &= ~(disc_sects - 1);
  66         }
  67
  68         if (flags & BLKDEV_DISCARD_SECURE) {
  69                 if (!blk_queue_secdiscard(q))
  70                         return -EOPNOTSUPP;
  71                 type |= REQ_SECURE;
  72         }
  73
  74         atomic_set(&bb.done, 1);
  75         bb.flags = 1 << BIO_UPTODATE;
  76         bb.wait = &wait;
  77
  78         while (nr_sects) {
  79                 bio = bio_alloc(gfp_mask, 1);
  80                 if (!bio) {
  81                         ret = -ENOMEM;
  82                         break;
  83                 }
  84
  85                 bio->bi_sector = sector;
  86                 bio->bi_end_io = bio_batch_end_io;
  87                 bio->bi_bdev = bdev;
  88                 bio->bi_private = &bb;
  89
  90                 if (nr_sects > max_discard_sectors) {
  91                         bio->bi_size = max_discard_sectors << 9;
  92                         nr_sects -= max_discard_sectors;
  93                         sector += max_discard_sectors;
  94                 } else {
  95                         bio->bi_size = nr_sects << 9;
  96                         nr_sects = 0;
  97                 }
  98
  99                 atomic_inc(&bb.done);
 100                 submit_bio(type, bio);
 101         }
 102
 103         /* Wait for bios in-flight */
 104         if (!atomic_dec_and_test(&bb.done))
 105                 wait_for_completion(&wait);
 106
 107         if (!test_bit(BIO_UPTODATE, &bb.flags))
 108                 ret = -EIO;
 109
 110         return ret;
 111 }
 112 EXPORT_SYMBOL(blkdev_issue_discard);
 113
 114 /**
 115  * blkdev_issue_zeroout - generate number of zero filed write bios
 116  * @bdev:       blockdev to issue
 117  * @sector:     start sector
 118  * @nr_sects:   number of sectors to write
 119  * @gfp_mask:   memory allocation flags (for bio_alloc)
 120  *
 121  * Description:
 122  *  Generate and issue number of bios with zerofiled pages.
 123  */
 124
 125 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 126                         sector_t nr_sects, gfp_t gfp_mask)
 127 {
 128         int ret;
 129         struct bio *bio;
 130         struct bio_batch bb;
 131         unsigned int sz;
 132         DECLARE_COMPLETION_ONSTACK(wait);
 133
 134         atomic_set(&bb.done, 1);
 135         bb.flags = 1 << BIO_UPTODATE;
 136         bb.wait = &wait;
 137
 138         ret = 0;
 139         while (nr_sects != 0) {
 140                 bio = bio_alloc(gfp_mask,
 141                                 min(nr_sects, (sector_t)BIO_MAX_PAGES));
 142                 if (!bio) {
 143                         ret = -ENOMEM;
 144                         break;
 145                 }
 146
 147                 bio->bi_sector = sector;
 148                 bio->bi_bdev   = bdev;
 149                 bio->bi_end_io = bio_batch_end_io;
 150                 bio->bi_private = &bb;
 151
 152                 while (nr_sects != 0) {
 153                         sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
 154                         ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
 155                         nr_sects -= ret >> 9;
 156                         sector += ret >> 9;
 157                         if (ret < (sz << 9))
 158                                 break;
 159                 }
 160                 ret = 0;
 161                 atomic_inc(&bb.done);
 162                 submit_bio(WRITE, bio);
 163         }
 164
 165         /* Wait for bios in-flight */
 166         if (!atomic_dec_and_test(&bb.done))
 167                 wait_for_completion(&wait);
 168
 169         if (!test_bit(BIO_UPTODATE, &bb.flags))
 170                 /* One of bios in the batch was completed with error.*/
 171                 ret = -EIO;
 172
 173         return ret;
 174 }
 175 EXPORT_SYMBOL(blkdev_issue_zeroout);