[PATCH] xfs: fix compilation warnings in xfs_sync_sb_buf when CONFIG_XFS_RT=n

When CONFIG_XFS_RT is disabled, xfs_log_rtsb() is a macro expanding to
(NULL), causing 'statement with no effect' and 'variable set but not
used' warnings.

Fix by removing the bp variable and passing xfs_trans_getsb(tp) directly
to xfs_log_rtsb().  This is safe because xfs_log_sb() already joins the
sb buffer to the transaction internally.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Fixes: b9ad0b9891dd ("xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf")
Signed-off-by: Yun Zhou <[email protected]>
---
 fs/xfs/libxfs/xfs_sb.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index fbb4505b1e9e..c4fa7fb0e39a 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -1470,17 +1470,15 @@ xfs_sync_sb_buf(
 	bool			update_rtsb)
 {
 	struct xfs_trans	*tp;
-	struct xfs_buf		*bp;
 	int			error;
 
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_sb, 0, 0, 0, &tp);
 	if (error)
 		return error;
 
-	bp = xfs_trans_getsb(tp);
 	xfs_log_sb(tp);
 	if (update_rtsb)
-		xfs_log_rtsb(tp, bp);
+		(void)xfs_log_rtsb(tp, xfs_trans_getsb(tp));
 	xfs_trans_set_sync(tp);
 	error = xfs_trans_commit(tp);
 	if (error)
-- 
2.43.0