dm table: remove merge_bvec sector restriction

Remove max_sector restriction - merge function replaced it.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 94116eaf4709..798e468103b8 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -506,14 +506,13 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
         rs->max_sectors =
                 min_not_zero(rs->max_sectors, q->max_sectors);
 
-        /* FIXME: Device-Mapper on top of RAID-0 breaks because DM
-         *        currently doesn't honor MD's merge_bvec_fn routine.
-         *        In this case, we'll force DM to use PAGE_SIZE or
-         *        smaller I/O, just to be safe. A better fix is in the
-         *        works, but add this for the time being so it will at
-         *        least operate correctly.
+        /*
+         * Check if merge fn is supported.
+         * If not we'll force DM to use PAGE_SIZE or
+         * smaller I/O, just to be safe.
          */
-        if (q->merge_bvec_fn)
+
+        if (q->merge_bvec_fn && !ti->type->merge)
                 rs->max_sectors =
                         min_not_zero(rs->max_sectors,
                                      (unsigned int) (PAGE_SIZE >> 9));