md/raid5: Compare apples to apples (or sectors to sectors)

commit e7597e69dec59b65c5525db1626b9d34afdfa678 upstream.

'max_discard_sectors' is in sectors, while 'stripe' is in bytes.

This fixes the problem where DISCARD would get disabled on some larger
RAID5 configurations (6 or more drives in my testing), while it worked
as expected with smaller configurations.

Fixes: 620125f2bf8 ("MD: raid5 trim support")
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b4f02c9959f23c1bb5e8feccb2b9bf6e1c59e862..7f770b0c0348ce5fce1700be900e68e35f967f55 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7014,8 +7014,8 @@ static int raid5_run(struct mddev *mddev)
                }
 
                if (discard_supported &&
-                  mddev->queue->limits.max_discard_sectors >= stripe &&
-                  mddev->queue->limits.discard_granularity >= stripe)
+                   mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
+                   mddev->queue->limits.discard_granularity >= stripe)
                        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
                                                mddev->queue);
                else