[TCP]: Fix sysctl_tcp_low_latency

When enabled, this should disable UCOPY prequeue'ing altogether,
but it does not due to a missing test.

Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/tcp.c

···
 
 		cleanup_rbuf(sk, copied);
 
-		if (tp->ucopy.task == user_recv) {
+		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
 			/* Install new reader */
 			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
 				user_recv = current;