From: Milan Broz <mbroz@redhat.com>
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: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
drivers/md/dm-linear.c | 37 ++++++++++++++++++++++++++++++++-----
1 files changed, 32 insertions(+), 5 deletions(-)
Index: linux-2.6.24/drivers/md/dm-linear.c
===================================================================
--- linux-2.6.24.orig/drivers/md/dm-linear.c 2008-02-05 19:16:10.000000000 +0000
+++ linux-2.6.24/drivers/md/dm-linear.c 2008-02-05 19:21:42.000000000 +0000
@@ -69,13 +69,25 @@ static void linear_dtr(struct dm_target
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 +126,30 @@ static int linear_ioctl(struct dm_target
return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg);
}
+static int linear_merge(struct dm_target *ti, sector_t bi_sector, unsigned int bi_size,
+ unsigned long bi_rw, 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;
+
+ return min(max_size, q->merge_bvec_fn(q, lc->dev->bdev,
+ linear_map_sector(ti, bi_sector),
+ bi_size, bi_rw, 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)