loop: Simplify discard granularity calc

[ Upstream commit d47de6a ]

A bdev discard granularity is always at least SECTOR_SIZE, so don't check
for a zero value.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241101092215.422428-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: f5c84ef ("loop: Add sanity check for read/write_iter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 722f6dece719e5a18ec949f4774eda302ec6d68c)
Signed-off-by: Jack Vogel <jack.vogel@oracle.com>

Author: johnpgarry

drivers/block/loop.c

@@ -713,8 +713,7 @@ static void loop_config_discard(struct loop_device *lo,
 		struct block_device *bdev = I_BDEV(inode);
 
 		max_discard_sectors = bdev_write_zeroes_sectors(bdev);
-		granularity = bdev_discard_granularity(bdev) ?:
-			bdev_physical_block_size(bdev);
+		granularity = bdev_discard_granularity(bdev);
 
 	/*
 	 * We use punch hole to reclaim the free space used by the