+ userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch added to -mm tree

+ userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: userfaultfd/selftests: use swap() instead of open coding it
has been added to the -mm tree.  Its filename is
     userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch

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------------------------------------------------------
From: Guo Zhengkui <guozhengkui@vivo.com>
Subject: userfaultfd/selftests: use swap() instead of open coding it

Address the following coccicheck warning:

tools/testing/selftests/vm/userfaultfd.c:1536:21-22: WARNING opportunity
for swap().
tools/testing/selftests/vm/userfaultfd.c:1540:33-34: WARNING opportunity
for swap().

by using swap() for the swapping of variable values and drop
`tmp_area` that is not needed any more.

`swap()` macro in userfaultfd.c is introduced in commit 681696862bc18
("selftests: vm: remove dependecy from internal kernel macros")

It has been tested with gcc (Debian 8.3.0-6) 8.3.0.

Link: https://lkml.kernel.org/r/20220407123141.4998-1-guozhengkui@vivo.com
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/vm/userfaultfd.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-use-swap-instead-of-open-coding-it
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -1422,7 +1422,6 @@ static void userfaultfd_pagemap_test(uns
 static int userfaultfd_stress(void)
 {
 	void *area;
-	char *tmp_area;
 	unsigned long nr;
 	struct uffdio_register uffdio_register;
 	struct uffd_stats uffd_stats[nr_cpus];
@@ -1533,13 +1532,9 @@ static int userfaultfd_stress(void)
 					    count_verify[nr], nr);
 
 		/* prepare next bounce */
-		tmp_area = area_src;
-		area_src = area_dst;
-		area_dst = tmp_area;
-
-		tmp_area = area_src_alias;
-		area_src_alias = area_dst_alias;
-		area_dst_alias = tmp_area;
+		swap(area_src, area_dst);
+
+		swap(area_src_alias, area_dst_alias);
 
 		uffd_stats_report(uffd_stats, nr_cpus);
 	}
_

Patches currently in -mm which might be from guozhengkui@vivo.com are

userfaultfd-selftests-use-swap-instead-of-open-coding-it.patch