[PATCH] userfaultfd: fix swap.cocci warnings

[PATCH] userfaultfd: fix swap.cocci warnings

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
CC: linux-kernel(a)vger.kernel.org
TO: Andrea Arcangeli <aarcange@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linux Memory Management List <linux-mm@kvack.org>
CC: linux-kernel(a)vger.kernel.org

From: kernel test robot <lkp@intel.com>

mm/userfaultfd.c:743:13-14: WARNING opportunity for swap()


 Check for opencoded swap() implementation.

Generated by: scripts/coccinelle/misc/swap.cocci

Fixes: e551a4a9e99d ("userfaultfd: UFFDIO_REMAP uABI")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
---

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git main
head:   597056f5070bec9190a9b6389eb5fcc07ce2cd14
commit: e551a4a9e99d2595c4f1c1ca7b6a62f4b70da1f4 [38/51] userfaultfd: UFFDIO_REMAP uABI
:::::: branch date: 16 hours ago
:::::: commit date: 16 hours ago

Please take the patch only if it's a positive warning. Thanks!

 mm/userfaultfd.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -737,12 +737,10 @@ void double_pt_lock(spinlock_t *ptl1,
 {
 	spinlock_t *ptl_tmp;
 
-	if (ptl1 > ptl2) {
+	if (ptl1 > ptl2)
+		
 		/* exchange ptl1 and ptl2 */
-		ptl_tmp = ptl1;
-		ptl1 = ptl2;
-		ptl2 = ptl_tmp;
-	}
+		swap(ptl1, ptl2);
 	/* lock in virtual address order to avoid lock inversion */
 	spin_lock(ptl1);
 	if (ptl1 != ptl2)

[andrea-aa:main 38/51] mm/userfaultfd.c:743:13-14: WARNING opportunity for swap()

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
CC: linux-kernel(a)vger.kernel.org
TO: Andrea Arcangeli <aarcange@redhat.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git main
head:   597056f5070bec9190a9b6389eb5fcc07ce2cd14
commit: e551a4a9e99d2595c4f1c1ca7b6a62f4b70da1f4 [38/51] userfaultfd: UFFDIO_REMAP uABI
:::::: branch date: 16 hours ago
:::::: commit date: 16 hours ago
config: x86_64-randconfig-c022 (https://download.01.org/0day-ci/archive/20220308/202203082010.aZticNAg-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>


cocci warnings: (new ones prefixed by >>)
>> mm/userfaultfd.c:743:13-14: WARNING opportunity for swap()

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org