From 52952d386342bf3ca9ce52c5861a1acfa28db073 Mon Sep 17 00:00:00 2001
From: Muhammad Usama Anjum <usama.anjum@collabora.com>
Date: Thu, 27 Jan 2022 16:26:17 +1100
Subject: [PATCH] selftests: vm: remove dependecy from internal kernel macros

The defination of swap() is used from kernel's internal header when this
test is built in source tree.  The build fails when this test is built out
of source tree as defination of swap() isn't found.  Selftests shouldn't
depend on kernel's internal header files.  They can only depend on uapi
header files.  Add the defination of swap() to fix the build error:

	gcc -Wall  -I/linux_mainline2/build/usr/include -no-pie    userfaultfd.c -lrt -lpthread -o /linux_mainline2/build/kselftest/vm/userfaultfd
	userfaultfd.c: In function `userfaultfd_stress':
	userfaultfd.c:1530:3: warning: implicit declaration of function `swap'; did you mean `swab'? [-Wimplicit-function-declaration]
	 1530 |   swap(area_src, area_dst);
	      |   ^~~~
	      |   swab
	/usr/bin/ld: /tmp/cclUUH7V.o: in function `userfaultfd_stress':
	userfaultfd.c:(.text+0x4d64): undefined reference to `swap'
	/usr/bin/ld: userfaultfd.c:(.text+0x4d82): undefined reference to `swap'
	collect2: error: ld returned 1 exit status

Link: https://lkml.kernel.org/r/20220119101531.2850400-11-usama.anjum@collabora.com
Fixes: 2c769ed7137a ("tools/testing/selftests/vm/userfaultfd.c: use swap() to make code cleaner")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Andr Almeida <andrealmeid@collabora.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: Mickal Salan <mic@digikod.net>
Cc: Minghao Chi <chi.minghao@zte.com.cn>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 tools/testing/selftests/vm/userfaultfd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index d3fd24f9fae8c..d2480ab930372 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -119,6 +119,9 @@ struct uffd_stats {
 				 ~(unsigned long)(sizeof(unsigned long long) \
 						  -  1)))
 
+#define swap(a, b) \
+	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
+
 const char *examples =
     "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
     "./userfaultfd anon 100 99999\n\n"