xfs: fix non-debug build warnings

There seem to be a couple of new set-but-unused build warnings
that gcc 4.9.3 is now warning about. These are not regressions, just
the compiler being more picky.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 092d652..9cf3a86 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -750,13 +750,13 @@
  * buffer (see xfs_buf_attach_iodone() below), then put the
  * buf log item at the front.
  */
-void
+int
 xfs_buf_item_init(
-	xfs_buf_t	*bp,
-	xfs_mount_t	*mp)
+	struct xfs_buf	*bp,
+	struct xfs_mount *mp)
 {
-	xfs_log_item_t		*lip = bp->b_fspriv;
-	xfs_buf_log_item_t	*bip;
+	struct xfs_log_item	*lip = bp->b_fspriv;
+	struct xfs_buf_log_item	*bip;
 	int			chunks;
 	int			map_size;
 	int			error;
@@ -770,12 +770,11 @@
 	 */
 	ASSERT(bp->b_target->bt_mount == mp);
 	if (lip != NULL && lip->li_type == XFS_LI_BUF)
-		return;
+		return 0;
 
 	bip = kmem_zone_zalloc(xfs_buf_item_zone, KM_SLEEP);
 	xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
 	bip->bli_buf = bp;
-	xfs_buf_hold(bp);
 
 	/*
 	 * chunks is the number of XFS_BLF_CHUNK size pieces the buffer
@@ -788,6 +787,11 @@
 	 */
 	error = xfs_buf_item_get_format(bip, bp->b_map_count);
 	ASSERT(error == 0);
+	if (error) {	/* to stop gcc throwing set-but-unused warnings */
+		kmem_zone_free(xfs_buf_item_zone, bip);
+		return error;
+	}
+
 
 	for (i = 0; i < bip->bli_format_count; i++) {
 		chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
@@ -807,6 +811,8 @@
 	if (bp->b_fspriv)
 		bip->bli_item.li_bio_list = bp->b_fspriv;
 	bp->b_fspriv = bip;
+	xfs_buf_hold(bp);
+	return 0;
 }