[XFS] optimize XFS_IS_REALTIME_INODE w/o realtime config

Use XFS_IS_REALTIME_INODE in more places, and #define it to 0 if
CONFIG_XFS_RT is off. This should be safe because mount checks in
xfs_rtmount_init:

so if we get mounted w/o CONFIG_XFS_RT, no realtime inodes should be
encountered after that.

Defining XFS_IS_REALTIME_INODE to 0 saves a bit of stack space,
presumeably gcc can optimize around the various "if (0)" type checks:

xfs_alloc_file_space -8 xfs_bmap_adjacent -16 xfs_bmapi -8
xfs_bmap_rtalloc -16 xfs_bunmapi -28 xfs_free_file_space -64 xfs_imap +8
<-- ? hmm. xfs_iomap_write_direct -12 xfs_qm_dqusage_adjust -4
xfs_qm_vop_chown_reserve -4

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30014a

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/xfs/xfs_rw.h b/fs/xfs/xfs_rw.h
index bcfe07aa7e6b..f87db5344ce6 100644
--- a/fs/xfs/xfs_rw.h
+++ b/fs/xfs/xfs_rw.h
@@ -32,7 +32,7 @@ struct xfs_mount;
 static inline xfs_daddr_t
 xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
 {
-        return (((ip)->i_d.di_flags & XFS_DIFLAG_REALTIME) ? \
+        return (XFS_IS_REALTIME_INODE(ip) ? \
                  (xfs_daddr_t)XFS_FSB_TO_BB((ip)->i_mount, (fsb)) : \
                  XFS_FSB_TO_DADDR((ip)->i_mount, (fsb)));
 }
@@ -53,7 +53,7 @@ xfs_get_extsz_hint(
 {
         xfs_extlen_t    extsz;
 
-        if (unlikely(ip->i_d.di_flags & XFS_DIFLAG_REALTIME)) {
+        if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
                 extsz = (ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE)
                                 ? ip->i_d.di_extsize
                                 : ip->i_mount->m_sb.sb_rextsize;