selftests/bpf: Add F_SETFL for fcntl

Incorrect arguments are passed to fcntl() in test_sockmap.c when invoking
it to set file status flags. If O_NONBLOCK is used as 2nd argument and
passed into fcntl, -EINVAL will be returned (See do_fcntl() in fs/fcntl.c).
The correct approach is to use F_SETFL as 2nd argument, O_NONBLOCK as
3rd.

Fixes: 16962b2 ("bpf: sockmap, add selftests")
Signed-off-by: Geliang Tang <[email protected]>

tools/testing/selftests/bpf/test_sockmap.c

@@ -603,7 +603,7 @@ static int msg_loop(int fd, int iov_count, int iov_length, int cnt,
 		struct timeval timeout;
 		fd_set w;
 
-		fcntl(fd, fd_flags);
+		fcntl(fd, F_SETFL, fd_flags);
 		/* Account for pop bytes noting each iteration of apply will
 		 * call msg_pop_data helper so we need to account for this
 		 * by calculating the number of apply iterations. Note user