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Commit 7bc3447b authored by Milan Broz's avatar Milan Broz Committed by Alasdair G Kergon
Browse files

dm: linear add merge 



This patch implements biovec merge function for linear target.

If the underlying device has merge function defined, call it.
If not, keep precomputed value.

Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent f6fccb12

drivers/md/dm-linear.c

+33 −5
Original line number Diff line number Diff line
@@ -69,13 +69,25 @@ static void linear_dtr(struct dm_target *ti) 
	kfree(lc);

}



static int linear_map(struct dm_target *ti, struct bio *bio,

		      union map_info *map_context)

static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)

{

	struct linear_c *lc = (struct linear_c *) ti->private;

	struct linear_c *lc = ti->private;



	return lc->start + (bi_sector - ti->begin);

}



static void linear_map_bio(struct dm_target *ti, struct bio *bio)

{

	struct linear_c *lc = ti->private;



	bio->bi_bdev = lc->dev->bdev;

	bio->bi_sector = lc->start + (bio->bi_sector - ti->begin);

	bio->bi_sector = linear_map_sector(ti, bio->bi_sector);

}



static int linear_map(struct dm_target *ti, struct bio *bio,

		      union map_info *map_context)

{

	linear_map_bio(ti, bio);



	return DM_MAPIO_REMAPPED;

}
@@ -114,15 +126,31 @@ static int linear_ioctl(struct dm_target *ti, struct inode *inode, 
	return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg);

}



static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,

			struct bio_vec *biovec, int max_size)

{

	struct linear_c *lc = ti->private;

	struct request_queue *q = bdev_get_queue(lc->dev->bdev);



	if (!q->merge_bvec_fn)

		return max_size;



	bvm->bi_bdev = lc->dev->bdev;

	bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);



	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));

}



static struct target_type linear_target = {

	.name   = "linear",

	.version= {1, 0, 2},

	.version= {1, 0, 3},

	.module = THIS_MODULE,

	.ctr    = linear_ctr,

	.dtr    = linear_dtr,

	.map    = linear_map,

	.status = linear_status,

	.ioctl  = linear_ioctl,

	.merge  = linear_merge,

};



int __init dm_linear_init(void)