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author | Dmitry Monakhov <dmonakhov@openvz.org> | 2010-04-28 17:55:08 +0400 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2010-04-28 19:47:36 +0200 |
commit | f31e7e4022841c43c53b847b86b1bf97a08b2c94 (patch) | |
tree | 738821236a4e84f790d597bb2cc04bd812668b6a /block/blk-lib.c | |
parent | f17e232e9237c231daf9f0f4b177c61218bcb2e4 (diff) | |
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blkdev: move blkdev_issue helper functions to separate file
Move blkdev_issue_discard from blk-barrier.c because it is
not barrier related.
Later the file will be populated by other helpers.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r-- | block/blk-lib.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c new file mode 100644 index 0000000..0dc4388 --- /dev/null +++ b/block/blk-lib.c @@ -0,0 +1,114 @@ +/* + * Functions related to generic helpers functions + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/scatterlist.h> + +#include "blk.h" + +static void blkdev_discard_end_io(struct bio *bio, int err) +{ + if (err) { + if (err == -EOPNOTSUPP) + set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); + clear_bit(BIO_UPTODATE, &bio->bi_flags); + } + + if (bio->bi_private) + complete(bio->bi_private); + __free_page(bio_page(bio)); + + bio_put(bio); +} + +/** + * blkdev_issue_discard - queue a discard + * @bdev: blockdev to issue discard for + * @sector: start sector + * @nr_sects: number of sectors to discard + * @gfp_mask: memory allocation flags (for bio_alloc) + * @flags: BLKDEV_IFL_* flags to control behaviour + * + * Description: + * Issue a discard request for the sectors in question. + */ +int blkdev_issue_discard(struct block_device *bdev, sector_t sector, + sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) +{ + DECLARE_COMPLETION_ONSTACK(wait); + struct request_queue *q = bdev_get_queue(bdev); + int type = flags & BLKDEV_IFL_BARRIER ? + DISCARD_BARRIER : DISCARD_NOBARRIER; + struct bio *bio; + struct page *page; + int ret = 0; + + if (!q) + return -ENXIO; + + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + + while (nr_sects && !ret) { + unsigned int sector_size = q->limits.logical_block_size; + unsigned int max_discard_sectors = + min(q->limits.max_discard_sectors, UINT_MAX >> 9); + + bio = bio_alloc(gfp_mask, 1); + if (!bio) + goto out; + bio->bi_sector = sector; + bio->bi_end_io = blkdev_discard_end_io; + bio->bi_bdev = bdev; + if (flags & BLKDEV_IFL_WAIT) + bio->bi_private = &wait; + + /* + * Add a zeroed one-sector payload as that's what + * our current implementations need. If we'll ever need + * more the interface will need revisiting. + */ + page = alloc_page(gfp_mask | __GFP_ZERO); + if (!page) + goto out_free_bio; + if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size) + goto out_free_page; + + /* + * And override the bio size - the way discard works we + * touch many more blocks on disk than the actual payload + * length. + */ + if (nr_sects > max_discard_sectors) { + bio->bi_size = max_discard_sectors << 9; + nr_sects -= max_discard_sectors; + sector += max_discard_sectors; + } else { + bio->bi_size = nr_sects << 9; + nr_sects = 0; + } + + bio_get(bio); + submit_bio(type, bio); + + if (flags & BLKDEV_IFL_WAIT) + wait_for_completion(&wait); + + if (bio_flagged(bio, BIO_EOPNOTSUPP)) + ret = -EOPNOTSUPP; + else if (!bio_flagged(bio, BIO_UPTODATE)) + ret = -EIO; + bio_put(bio); + } + return ret; +out_free_page: + __free_page(page); +out_free_bio: + bio_put(bio); +out: + return -ENOMEM; +} +EXPORT_SYMBOL(blkdev_issue_discard); |