mm: userfaultfd: use swap() in double_pt_lock()

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

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

Link: https://lkml.kernel.org/r/20240531091643.67778-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9266
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index defa5109cc62ac2ce268f988246736567d95ff0f..5e7f2801698ac5c634ad8464a98fa0b2108fab6c 100644 (file)
--- 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)