xfs: remove XFS_HSIZE

XFS_HSIZE is an extremly confusing way to calculate the size of handle_t.
Given that handle_t always only had two sizes, and one of them isn't
even covered by XFS_HSIZE to start with just remove the macro and use
a constant sizeof expression.

Note that XFS_HSIZE isn't used in xfsprogs, xfsdump or xfstests either.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_fs.h

@@ -446,10 +446,6 @@ typedef struct xfs_handle {
 } xfs_handle_t;
 #define ha_fsid ha_u._ha_fsid
 
-#define XFS_HSIZE(handle)	(((char *) &(handle).ha_fid.fid_pad	 \
-				 - (char *) &(handle))			  \
-				 + (handle).ha_fid.fid_len)
-
 /*
  * Structure passed to XFS_IOC_SWAPEXT
  */

fs/xfs/xfs_ioctl.c

@@ -120,8 +120,7 @@ xfs_find_handle(
 		handle.ha_fid.fid_pad = 0;
 		handle.ha_fid.fid_gen = inode->i_generation;
 		handle.ha_fid.fid_ino = ip->i_ino;
-
-		hsize = XFS_HSIZE(handle);
+		hsize = sizeof(xfs_handle_t);
 	}
 
 	error = -EFAULT;