loop: Fix missing discard support when using LOOP_CONFIGURE

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: <[email protected]> # 5.8.x-
Fixes: 3448914 ("loop: Add LOOP_CONFIGURE ioctl")
Signed-off-by: Kristian Klausen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: klausenbusk

drivers/block/loop.c

@@ -1154,6 +1154,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	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);