Split max_io_len_target_boundary out of max_io_len so that the discard
support can make use of it without duplicating max_io_len code.
Avoiding max_io_len's split_io logic enables DM's discard support to
submit the entire discard request to a target. But discards must still
be split on target boundaries.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
Index: linux-2.6-block/drivers/md/dm.c
===================================================================
--- linux-2.6-block.orig/drivers/md/dm.c
+++ linux-2.6-block/drivers/md/dm.c
@@ -1029,11 +1029,20 @@ static void end_clone_request(struct req
dm_complete_request(clone, error);
}
-static sector_t max_io_len(struct mapped_device *md,
- sector_t sector, struct dm_target *ti)
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti,
+ sector_t *offset_p)
{
sector_t offset = sector - ti->begin;
- sector_t len = ti->len - offset;
+ if (offset_p)
+ *offset_p = offset;
+
+ return ti->len - offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+{
+ sector_t offset;
+ sector_t len = max_io_len_target_boundary(sector, ti, &offset);
/*
* Does the target need to split even further ?
@@ -1257,7 +1266,7 @@ static int __clone_and_map_discard(struc
if (!ti->num_discard_requests)
return -EOPNOTSUPP;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
if (ci->sector_count > max)
/*
@@ -1289,7 +1298,7 @@ static int __clone_and_map(struct clone_
if (!dm_target_is_valid(ti))
return -EIO;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
if (ci->sector_count <= max) {
/*
@@ -1340,7 +1349,7 @@ static int __clone_and_map(struct clone_
if (!dm_target_is_valid(ti))
return -EIO;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
}
len = min(remaining, max);
@@ -1427,7 +1436,7 @@ static int dm_merge_bvec(struct request_
/*
* Find maximum amount of I/O that won't need splitting
*/
- max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
+ max_sectors = min(max_io_len(bvm->bi_sector, ti),
(sector_t) BIO_MAX_SECTORS);
max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
if (max_size < 0)
--
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