xfs: do not use xfs_mod_incore_sb for per-cpu counters

Export xfs_icsb_modify_counters and always use it for modifying
the per-cpu counters.  Remove support for per-cpu counters from
xfs_mod_incore_sb to simplify it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index a9d366e..6509c07 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -91,6 +91,8 @@
 extern void	xfs_icsb_destroy_counters(struct xfs_mount *);
 extern void	xfs_icsb_sync_counters(struct xfs_mount *, int);
 extern void	xfs_icsb_sync_counters_locked(struct xfs_mount *, int);
+extern int	xfs_icsb_modify_counters(struct xfs_mount *, xfs_sb_field_t,
+						int64_t, int);
 
 #else
 #define xfs_icsb_init_counters(mp)		(0)
@@ -98,6 +100,8 @@
 #define xfs_icsb_reinit_counters(mp)		do { } while (0)
 #define xfs_icsb_sync_counters(mp, flags)	do { } while (0)
 #define xfs_icsb_sync_counters_locked(mp, flags) do { } while (0)
+#define xfs_icsb_modify_counters(mp, field, delta, rsvd) \
+	xfs_mod_incore_sb(mp, field, delta, rsvd)
 #endif
 
 typedef struct xfs_mount {