[PATCH] mm: userfaultfd: Use swap() in double_pt_lock()

[Jiapeng Chong]

Use existing swap() function rather than duplicating its implementation.

/mm/userfaultfd.c:1006:13-14: WARNING opportunity for swap()

Reported-by: Abaci Robot <abaci@xxxxxxxxxxxxxxxxx>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9266
Signed-off-by: Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx>
---
 mm/userfaultfd.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index defa5109cc62..5e7f2801698a 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -995,14 +995,8 @@ void double_pt_lock(spinlock_t *ptl1,
 	__acquires(ptl1)
 	__acquires(ptl2)
 {
-	spinlock_t *ptl_tmp;
-
-	if (ptl1 > ptl2) {
-		/* exchange ptl1 and ptl2 */
-		ptl_tmp = ptl1;
-		ptl1 = ptl2;
-		ptl2 = ptl_tmp;
-	}
+	if (ptl1 > ptl2)
+		swap(ptl1, ptl2);
 	/* lock in virtual address order to avoid lock inversion */
 	spin_lock(ptl1);
 	if (ptl1 != ptl2)
-- 
2.20.1.7.g153144c