xfs: abstract out dev_t conversions

And move them to xfs_linux.h so that xfsprogs can stub them out more
easily.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_inode_fork.c

@@ -42,11 +42,6 @@ STATIC int xfs_iformat_local(xfs_inode_t *, xfs_dinode_t *, int, int);
 STATIC int xfs_iformat_extents(xfs_inode_t *, xfs_dinode_t *, int);
 STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);
 
-static inline dev_t xfs_to_linux_dev_t(xfs_dev_t dev)
-{
-	return MKDEV(sysv_major(dev) & 0x1ff, sysv_minor(dev));
-}
-
 /*
  * Copy inode type and data and attr format specific information from the
  * on-disk inode to the in-core inode and fork structures.  For fifos, devices,
@@ -792,7 +787,8 @@ xfs_iflush_fork(
 	case XFS_DINODE_FMT_DEV:
 		if (iip->ili_fields & XFS_ILOG_DEV) {
 			ASSERT(whichfork == XFS_DATA_FORK);
-			xfs_dinode_put_rdev(dip, sysv_encode_dev(VFS_I(ip)->i_rdev));
+			xfs_dinode_put_rdev(dip,
+					linux_to_xfs_dev_t(VFS_I(ip)->i_rdev));
 		}
 		break;
 

fs/xfs/xfs_linux.h

@@ -204,6 +204,16 @@ static inline kgid_t xfs_gid_to_kgid(uint32_t gid)
 	return make_kgid(&init_user_ns, gid);
 }
 
+static inline dev_t xfs_to_linux_dev_t(xfs_dev_t dev)
+{
+	return MKDEV(sysv_major(dev) & 0x1ff, sysv_minor(dev));
+}
+
+static inline xfs_dev_t linux_to_xfs_dev_t(dev_t dev)
+{
+	return sysv_encode_dev(dev);
+}
+
 /*
  * Various platform dependent calls that don't fit anywhere else
  */