SOCK_MIN_RCVBUF
WRITE_ONCE(sk->sk_rcvbuf, max_t(int, val * 2, SOCK_MIN_RCVBUF));
static int min_rcvbuf = SOCK_MIN_RCVBUF;
new_window_clamp = max_t(int, SOCK_MIN_RCVBUF / 2, val);
val = clamp_t(int, val, (SOCK_MIN_RCVBUF + 1) / 2,
static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;