samples/bpf: xdpsock: Use common code to handle signal and main exit

Add code to do cleanup for signals and application completion in a unified
fashion. The signal handler sets benckmark_done flag terminating the
threads. The cleanup is called before returning from main() function.
Signed-off-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191220085530.4980-3-jay.jayatheerthan@intel.com

samples/bpf/xdpsock_user.c

@@ -209,6 +209,11 @@ static void remove_xdp_program(void)
 }
 
 static void int_exit(int sig)
+{
+	benchmark_done = true;
+}
+
+static void xdpsock_cleanup(void)
 {
 	struct xsk_umem *umem = xsks[0]->umem->umem;
 	int i;
@@ -218,8 +223,6 @@ static void int_exit(int sig)
 		xsk_socket__delete(xsks[i]->xsk);
 	(void)xsk_umem__delete(umem);
 	remove_xdp_program();
-
-	exit(EXIT_SUCCESS);
 }
 
 static void __exit_with_error(int error, const char *file, const char *func,
@@ -893,5 +896,7 @@ int main(int argc, char **argv)
 
 	pthread_join(pt, NULL);
 
+	xdpsock_cleanup();
+
 	return 0;
 }