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 681696862b
("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>
1bf0831383