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_trans.c b/fs/xfs/xfs_trans.c
index 1c47eda..73cf8f4 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -696,7 +696,7 @@
 	 * fail if the count would go below zero.
 	 */
 	if (blocks > 0) {
-		error = xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FDBLOCKS,
+		error = xfs_icsb_modify_counters(tp->t_mountp, XFS_SBS_FDBLOCKS,
 					  -((int64_t)blocks), rsvd);
 		if (error != 0) {
 			current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
@@ -767,7 +767,7 @@
 
 undo_blocks:
 	if (blocks > 0) {
-		(void) xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FDBLOCKS,
+		xfs_icsb_modify_counters(tp->t_mountp, XFS_SBS_FDBLOCKS,
 					 (int64_t)blocks, rsvd);
 		tp->t_blk_res = 0;
 	}