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>
---
drivers/md/dm-linear.c | 38 ++++++++++++++++++++++++++++++++++----
1 files changed, 34 insertions(+), 4 deletions(-)
Index: linux-2.6.21/drivers/md/dm-linear.c
===================================================================
--- linux-2.6.21.orig/drivers/md/dm-linear.c 2007-05-01 17:38:30.000000000 +0100
+++ linux-2.6.21/drivers/md/dm-linear.c 2007-05-01 17:40:58.000000000 +0100
@@ -69,13 +69,18 @@ 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 void linear_map_bio(struct dm_target *ti, struct bio *bio)
{
- struct linear_c *lc = (struct linear_c *) ti->private;
+ struct linear_c *lc = ti->private;
bio->bi_bdev = lc->dev->bdev;
bio->bi_sector = lc->start + (bio->bi_sector - ti->begin);
+}
+
+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 +119,40 @@ 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, struct bio *bio,
+ struct bio_vec *biovec, int len)
+{
+ struct linear_c *lc = ti->private;
+ request_queue_t *q = bdev_get_queue(lc->dev->bdev);
+
+ if (q->merge_bvec_fn) {
+ /* FIXME Yuck. Shouldn't these be merge_bvec_fn parameters? Why does the bio get passed around here at all? */
+ /* FIXME Use helper function (or macro) to save this for now. */
+ sector_t org_sec = bio->bi_sector;
+ struct block_device *org_dev = bio->bi_bdev;
+
+ linear_map_bio(ti, bio);
+
+ len = q->merge_bvec_fn(q, bio, biovec);
+
+ /* FIXME Use helper function to restore this */
+ bio->bi_bdev = org_dev;
+ bio->bi_sector = org_sec;
+ }
+
+ return len;
+}
+
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)