selftest/timerns: fix clang build failures for abs() calls

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...clang warns about mismatches between the expected and required
integer length being supplied to abs(3).

Fix this by using the correct variant of abs(3): labs(3) or llabs(3), in
these cases.
Reviewed-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Andrei Vagin <avagin@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/timens/exec.c

@@ -30,7 +30,7 @@ int main(int argc, char *argv[])
 
 		for (i = 0; i < 2; i++) {
 			_gettime(CLOCK_MONOTONIC, &tst, i);
-			if (abs(tst.tv_sec - now.tv_sec) > 5)
+			if (labs(tst.tv_sec - now.tv_sec) > 5)
 				return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec);
 		}
 		return 0;
@@ -50,7 +50,7 @@ int main(int argc, char *argv[])
 
 	for (i = 0; i < 2; i++) {
 		_gettime(CLOCK_MONOTONIC, &tst, i);
-		if (abs(tst.tv_sec - now.tv_sec) > 5)
+		if (labs(tst.tv_sec - now.tv_sec) > 5)
 			return pr_fail("%ld %ld\n",
 					now.tv_sec, tst.tv_sec);
 	}
@@ -70,7 +70,7 @@ int main(int argc, char *argv[])
 		/* Check that a child process is in the new timens. */
 		for (i = 0; i < 2; i++) {
 			_gettime(CLOCK_MONOTONIC, &tst, i);
-			if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5)
+			if (labs(tst.tv_sec - now.tv_sec - OFFSET) > 5)
 				return pr_fail("%ld %ld\n",
 						now.tv_sec + OFFSET, tst.tv_sec);
 		}

tools/testing/selftests/timens/timer.c

@@ -56,7 +56,7 @@ int run_test(int clockid, struct timespec now)
 			return pr_perror("timerfd_gettime");
 
 		elapsed = new_value.it_value.tv_sec;
-		if (abs(elapsed - 3600) > 60) {
+		if (llabs(elapsed - 3600) > 60) {
 			ksft_test_result_fail("clockid: %d elapsed: %lld\n",
 					      clockid, elapsed);
 			return 1;

tools/testing/selftests/timens/timerfd.c

@@ -61,7 +61,7 @@ int run_test(int clockid, struct timespec now)
 			return pr_perror("timerfd_gettime(%d)", clockid);
 
 		elapsed = new_value.it_value.tv_sec;
-		if (abs(elapsed - 3600) > 60) {
+		if (llabs(elapsed - 3600) > 60) {
 			ksft_test_result_fail("clockid: %d elapsed: %lld\n",
 					      clockid, elapsed);
 			return 1;

tools/testing/selftests/timens/vfork_exec.c

@@ -32,7 +32,7 @@ static void *tcheck(void *_args)
 
 	for (i = 0; i < 2; i++) {
 		_gettime(CLOCK_MONOTONIC, &tst, i);
-		if (abs(tst.tv_sec - now->tv_sec) > 5) {
+		if (labs(tst.tv_sec - now->tv_sec) > 5) {
 			pr_fail("%s: in-thread: unexpected value: %ld (%ld)\n",
 				args->tst_name, tst.tv_sec, now->tv_sec);
 			return (void *)1UL;
@@ -64,7 +64,7 @@ static int check(char *tst_name, struct timespec *now)
 
 	for (i = 0; i < 2; i++) {
 		_gettime(CLOCK_MONOTONIC, &tst, i);
-		if (abs(tst.tv_sec - now->tv_sec) > 5)
+		if (labs(tst.tv_sec - now->tv_sec) > 5)
 			return pr_fail("%s: unexpected value: %ld (%ld)\n",
 					tst_name, tst.tv_sec, now->tv_sec);
 	}