tcp: do not assume TCP code is non preemptible

We want to to make TCP stack preemptible, as draining prequeue and backlog queues can take lot of time. Many SNMP updates were assuming that BH (and preemption) was disabled. Need to convert some __NET_INC_STATS() calls to NET_INC_STATS() and some __TCP_INC_STATS() to TCP_INC_STATS() Before using this_cpu_ptr(net->ipv4.tcp_sk) in tcp_v4_send_reset() and tcp_v4_send_ack(), we add an explicit preempt disabled section. Signed-off-by: Eric Dumazet <[email protected]> Acked-by: Soheil Hassas Yeganeh <[email protected]> Signed-off-by: David S. Miller <[email protected]>
chewitt · May 2, 2016 · c10d931 · c10d931
1 parent 5e59c83
commit c10d931
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Showing 11 changed files with 104 additions and 99 deletions.
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
@@ -3095,7 +3095,7 @@ void tcp_done(struct sock *sk)
 	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
 
 	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
-		__TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
+		TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
 
 	tcp_set_state(sk, TCP_CLOSE);
 	tcp_clear_xmit_timers(sk);

diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c
@@ -155,11 +155,11 @@ static void tcp_cdg_hystart_update(struct sock *sk)
 
 			ca->last_ack = now_us;
 			if (after(now_us, ca->round_start + base_owd)) {
-				__NET_INC_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTTRAINDETECT);
-				__NET_ADD_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTTRAINCWND,
-						tp->snd_cwnd);
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTTRAINDETECT);
+				NET_ADD_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTTRAINCWND,
+					      tp->snd_cwnd);
 				tp->snd_ssthresh = tp->snd_cwnd;
 				return;
 			}
@@ -174,11 +174,11 @@ static void tcp_cdg_hystart_update(struct sock *sk)
 					 125U);
 
 			if (ca->rtt.min > thresh) {
-				__NET_INC_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTDELAYDETECT);
-				__NET_ADD_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTDELAYCWND,
-						tp->snd_cwnd);
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTDELAYDETECT);
+				NET_ADD_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTDELAYCWND,
+					      tp->snd_cwnd);
 				tp->snd_ssthresh = tp->snd_cwnd;
 			}
 		}

diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
@@ -402,11 +402,11 @@ static void hystart_update(struct sock *sk, u32 delay)
 			ca->last_ack = now;
 			if ((s32)(now - ca->round_start) > ca->delay_min >> 4) {
 				ca->found |= HYSTART_ACK_TRAIN;
-				__NET_INC_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTTRAINDETECT);
-				__NET_ADD_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTTRAINCWND,
-						tp->snd_cwnd);
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTTRAINDETECT);
+				NET_ADD_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTTRAINCWND,
+					      tp->snd_cwnd);
 				tp->snd_ssthresh = tp->snd_cwnd;
 			}
 		}
@@ -423,11 +423,11 @@ static void hystart_update(struct sock *sk, u32 delay)
 			if (ca->curr_rtt > ca->delay_min +
 			    HYSTART_DELAY_THRESH(ca->delay_min >> 3)) {
 				ca->found |= HYSTART_DELAY;
-				__NET_INC_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTDELAYDETECT);
-				__NET_ADD_STATS(sock_net(sk),
-						LINUX_MIB_TCPHYSTARTDELAYCWND,
-						tp->snd_cwnd);
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTDELAYDETECT);
+				NET_ADD_STATS(sock_net(sk),
+					      LINUX_MIB_TCPHYSTARTDELAYCWND,
+					      tp->snd_cwnd);
 				tp->snd_ssthresh = tp->snd_cwnd;
 			}
 		}

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
@@ -255,9 +255,9 @@ static bool tcp_fastopen_queue_check(struct sock *sk)
 		spin_lock(&fastopenq->lock);
 		req1 = fastopenq->rskq_rst_head;
 		if (!req1 || time_after(req1->rsk_timer.expires, jiffies)) {
-			spin_unlock(&fastopenq->lock);
 			__NET_INC_STATS(sock_net(sk),
 					LINUX_MIB_TCPFASTOPENLISTENOVERFLOW);
+			spin_unlock(&fastopenq->lock);
 			return false;
 		}
 		fastopenq->rskq_rst_head = req1->dl_next;
@@ -282,7 +282,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 	struct sock *child;
 
 	if (foc->len == 0) /* Client requests a cookie */
-		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENCOOKIEREQD);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENCOOKIEREQD);
 
 	if (!((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) &&
 	      (syn_data || foc->len >= 0) &&
@@ -311,13 +311,13 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 		child = tcp_fastopen_create_child(sk, skb, dst, req);
 		if (child) {
 			foc->len = -1;
-			__NET_INC_STATS(sock_net(sk),
-					LINUX_MIB_TCPFASTOPENPASSIVE);
+			NET_INC_STATS(sock_net(sk),
+				      LINUX_MIB_TCPFASTOPENPASSIVE);
 			return child;
 		}
-		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
 	} else if (foc->len > 0) /* Client presents an invalid cookie */
-		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
 
 	valid_foc.exp = foc->exp;
 	*foc = valid_foc;