From: Geliang Tang <tanggeliang@kylinos.cn>

BPF tests fail sometimes with "bytes != total_bytes" errors:

 # test_default:PASS:sched_init:default 0 nsec
 # send_data:PASS:pthread_create 0 nsec
 # send_data:FAIL:recv 936000 != 10485760 nr_recv:-1 errno:11
 # default: 3041 ms
 # server:FAIL:send 7579500 != 10485760 nr_sent:-1 errno:11
 # send_data:FAIL:pthread_join thread_ret:-11 \
		test_default:PASS:has_bytes_sent addr_1 0 nsec
 # test_default:PASS:has_bytes_sent addr_2 0 nsec
 # close_netns:PASS:setns 0 nsec

Here errno 11 is EAGAIN. This patch sets server socket to nonblock
to fix this. It makes BPF tests stable.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/prog_tests/mptcp.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 6e28215d7404..d3d51aee440d 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -88,6 +88,16 @@ static void cleanup_netns(struct nstoken *nstoken)
 	SYS_NOFAIL("ip netns del %s", NS_TEST);
 }
 
+static int set_nonblock(int fd)
+{
+	int flags = fcntl(fd, F_GETFL);
+
+	if (flags == -1)
+		return -1;
+
+	return fcntl(fd, flags | O_NONBLOCK);
+}
+
 static int verify_tsk(int map_fd, int client_fd)
 {
 	int err, cfd = client_fd;
@@ -466,6 +476,7 @@ static void test_default(void)
 	server_fd = start_mptcp_server(AF_INET, ADDR_1, PORT_1, 0);
 	client_fd = connect_to_fd(server_fd, 0);
 
+	set_nonblock(server_fd);
 	send_data(server_fd, client_fd, "default");
 	ASSERT_OK(has_bytes_sent(ADDR_1), "has_bytes_sent addr_1");
 	ASSERT_OK(has_bytes_sent(ADDR_2), "has_bytes_sent addr_2");
@@ -639,6 +650,7 @@ static void test_burst(void)
 	server_fd = start_mptcp_server(AF_INET, ADDR_1, PORT_1, 0);
 	client_fd = connect_to_fd(server_fd, 0);
 
+	set_nonblock(server_fd);
 	send_data(server_fd, client_fd, "bpf_burst");
 	ASSERT_OK(has_bytes_sent(ADDR_1), "has_bytes_sent addr 1");
 	ASSERT_OK(has_bytes_sent(ADDR_2), "has_bytes_sent addr 2");
-- 
2.40.1