[PATCH 5.12 109/700] loop: Fix missing discard support when using LOOP_CONFIGURE

[Greg Kroah-Hartman]

From: Kristian Klausen <kristian@xxxxxxxxxx>

commit 2b9ac22b12a266eb4fec246a07b504dd4983b16b upstream.

Without calling loop_config_discard() the discard flag and parameters
aren't set/updated for the loop device and worst-case they could
indicate discard support when it isn't the case (ex: if the
LOOP_SET_STATUS ioctl was used with a different file prior to
LOOP_CONFIGURE).

Cc: <stable@xxxxxxxxxxxxxxx> # 5.8.x-
Fixes: 3448914e8cc5 ("loop: Add LOOP_CONFIGURE ioctl")
Signed-off-by: Kristian Klausen <kristian@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210618115157.31452-1-kristian@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/block/loop.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1153,6 +1153,7 @@ static int loop_configure(struct loop_de
 	blk_queue_physical_block_size(lo->lo_queue, bsize);
 	blk_queue_io_min(lo->lo_queue, bsize);
 
+	loop_config_discard(lo);
 	loop_update_rotational(lo);
 	loop_update_dio(lo);
 	loop_sysfs_init(lo);