f31e7e4022
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>
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
/*
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* Functions related to generic helpers functions
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/scatterlist.h>
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#include "blk.h"
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static void blkdev_discard_end_io(struct bio *bio, int err)
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{
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if (err) {
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if (err == -EOPNOTSUPP)
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set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
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clear_bit(BIO_UPTODATE, &bio->bi_flags);
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}
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if (bio->bi_private)
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complete(bio->bi_private);
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__free_page(bio_page(bio));
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bio_put(bio);
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}
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/**
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* blkdev_issue_discard - queue a discard
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* @bdev: blockdev to issue discard for
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* @sector: start sector
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* @nr_sects: number of sectors to discard
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @flags: BLKDEV_IFL_* flags to control behaviour
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*
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* Description:
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* Issue a discard request for the sectors in question.
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*/
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int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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struct request_queue *q = bdev_get_queue(bdev);
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int type = flags & BLKDEV_IFL_BARRIER ?
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DISCARD_BARRIER : DISCARD_NOBARRIER;
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struct bio *bio;
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struct page *page;
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int ret = 0;
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if (!q)
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return -ENXIO;
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if (!blk_queue_discard(q))
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return -EOPNOTSUPP;
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while (nr_sects && !ret) {
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unsigned int sector_size = q->limits.logical_block_size;
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unsigned int max_discard_sectors =
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min(q->limits.max_discard_sectors, UINT_MAX >> 9);
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bio = bio_alloc(gfp_mask, 1);
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if (!bio)
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goto out;
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bio->bi_sector = sector;
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bio->bi_end_io = blkdev_discard_end_io;
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bio->bi_bdev = bdev;
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if (flags & BLKDEV_IFL_WAIT)
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bio->bi_private = &wait;
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/*
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* Add a zeroed one-sector payload as that's what
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* our current implementations need. If we'll ever need
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* more the interface will need revisiting.
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*/
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page = alloc_page(gfp_mask | __GFP_ZERO);
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if (!page)
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goto out_free_bio;
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if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
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goto out_free_page;
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/*
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* And override the bio size - the way discard works we
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* touch many more blocks on disk than the actual payload
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* length.
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*/
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if (nr_sects > max_discard_sectors) {
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bio->bi_size = max_discard_sectors << 9;
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nr_sects -= max_discard_sectors;
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sector += max_discard_sectors;
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} else {
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bio->bi_size = nr_sects << 9;
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nr_sects = 0;
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}
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bio_get(bio);
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submit_bio(type, bio);
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if (flags & BLKDEV_IFL_WAIT)
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wait_for_completion(&wait);
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if (bio_flagged(bio, BIO_EOPNOTSUPP))
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ret = -EOPNOTSUPP;
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else if (!bio_flagged(bio, BIO_UPTODATE))
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ret = -EIO;
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bio_put(bio);
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}
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return ret;
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out_free_page:
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__free_page(page);
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out_free_bio:
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bio_put(bio);
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out:
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return -ENOMEM;
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}
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EXPORT_SYMBOL(blkdev_issue_discard);
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