[PATCH 5.4 14/76] dm raid: fix discard limits for raid1

Greg Kroah-Hartman
2021-01-18T11:45:09Z

From: Mike Snitzer <snitzer@redhat.com>

commit cc07d72bf350b77faeffee1c37bc52197171473f upstream.

Block core warned that discard_granularity was 0 for dm-raid with
personality of raid1. Reason is that raid_io_hints() was incorrectly
special-casing raid1 rather than raid0.

Fix raid_io_hints() by removing discard limits settings for
raid1. Check for raid0 instead.

Fixes: 61697a6abd24a ("dm: eliminate 'split_discard_bios' flag from DM target interface")
Cc: stable@vger.kernel.org
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Stephan Bärwolf <stephan@matrixstorm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-raid.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3744,10 +3744,10 @@ static void raid_io_hints(struct dm_targ
blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));

/*
- * RAID1 and RAID10 personalities require bio splitting,
- * RAID0/4/5/6 don't and process large discard bios properly.
+ * RAID0 and RAID10 personalities require bio splitting,
+ * RAID1/4/5/6 don't and process large discard bios properly.
*/
- if (rs_is_raid1(rs) || rs_is_raid10(rs)) {
+ if (rs_is_raid0(rs) || rs_is_raid10(rs)) {
limits->discard_granularity = chunk_size_bytes;
limits->max_discard_sectors = rs->md.chunk_sectors;
}