loop: fix type of block size

PAGE_SIZE may be 64K, and the max block size can be PAGE_SIZE, so any
variable for holding block size can't be defined as 'unsigned short'.

Unfortunately commit 473516b ("loop: use the atomic queue limits
update API") passes 'bsize' with type of 'unsigned short' to
loop_reconfigure_limits(), and causes LTP/ioctl_loop06 test failure:

  12 ioctl_loop06.c:76: TINFO: Using LOOP_SET_BLOCK_SIZE with arg > PAGE_SIZE
  13 ioctl_loop06.c:59: TFAIL: Set block size succeed unexpectedly
  ...
  18 ioctl_loop06.c:76: TINFO: Using LOOP_CONFIGURE with block_size > PAGE_SIZE
  19 ioctl_loop06.c:59: TFAIL: Set block size succeed unexpectedly

Fixes the issue by defining 'block size' variable with 'unsigned int', which is
aligned with block layer's definition.

(improve commit log & add fixes tag)

Fixes: 473516b ("loop: use the atomic queue limits update API")
Cc: John Garry <john.g.garry@oracle.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Li Wang <liwang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241109022744.1126003-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: wangli5665

drivers/block/loop.c

@@ -173,7 +173,7 @@ static loff_t get_loop_size(struct loop_device *lo, struct file *file)
 static bool lo_bdev_can_use_dio(struct loop_device *lo,
 		struct block_device *backing_bdev)
 {
-	unsigned short sb_bsize = bdev_logical_block_size(backing_bdev);
+	unsigned int sb_bsize = bdev_logical_block_size(backing_bdev);
 
 	if (queue_logical_block_size(lo->lo_queue) < sb_bsize)
 		return false;
@@ -976,7 +976,7 @@ loop_set_status_from_info(struct loop_device *lo,
 	return 0;
 }
 
-static unsigned short loop_default_blocksize(struct loop_device *lo,
+static unsigned int loop_default_blocksize(struct loop_device *lo,
 		struct block_device *backing_bdev)
 {
 	/* In case of direct I/O, match underlying block size */
@@ -985,7 +985,7 @@ static unsigned short loop_default_blocksize(struct loop_device *lo,
 	return SECTOR_SIZE;
 }
 
-static int loop_reconfigure_limits(struct loop_device *lo, unsigned short bsize)
+static int loop_reconfigure_limits(struct loop_device *lo, unsigned int bsize)
 {
 	struct file *file = lo->lo_backing_file;
 	struct inode *inode = file->f_mapping->host;