[dm-devel] [PATCH] dm-raid: stack limits instead of overwriting them.

[Mikulas Patocka]

This patch fixes a warning WARN_ON_ONCE(!q->limits.discard_granularity).
The reason is that the function raid_io_hints overwrote
limits->discard_granularity with zero. We need to properly stack the
limits instead of overwriting them.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Cc: stable at vger.kernel.org

---
 drivers/md/dm-raid.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/md/dm-raid.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-raid.c	2020-09-24 18:16:45.000000000 +0200
+++ linux-2.6/drivers/md/dm-raid.c	2020-09-24 18:16:45.000000000 +0200
@@ -3734,8 +3734,8 @@ static void raid_io_hints(struct dm_targ
 	 * RAID0/4/5/6 don't and process large discard bios properly.
 	 */
 	if (rs_is_raid1(rs) || rs_is_raid10(rs)) {
-		limits->discard_granularity = chunk_size_bytes;
-		limits->max_discard_sectors = rs->md.chunk_sectors;
+		limits->discard_granularity = max(limits->discard_granularity, chunk_size_bytes);
+		limits->max_discard_sectors = min_not_zero(limits->max_discard_sectors, (unsigned)rs->md.chunk_sectors);
 	}
 }