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Diffstat (limited to 'net/ipv4/tcp_fastopen.c')
-rw-r--r--net/ipv4/tcp_fastopen.c28
1 files changed, 24 insertions, 4 deletions
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 1a9fbd5448a7..62ba8d0f2c60 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -496,8 +496,18 @@ void tcp_fastopen_active_disable(struct sock *sk)
{
struct net *net = sock_net(sk);
+ if (!sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout)
+ return;
+
+ /* Paired with READ_ONCE() in tcp_fastopen_active_should_disable() */
+ WRITE_ONCE(net->ipv4.tfo_active_disable_stamp, jiffies);
+
+ /* Paired with smp_rmb() in tcp_fastopen_active_should_disable().
+ * We want net->ipv4.tfo_active_disable_stamp to be updated first.
+ */
+ smp_mb__before_atomic();
atomic_inc(&net->ipv4.tfo_active_disable_times);
- net->ipv4.tfo_active_disable_stamp = jiffies;
+
NET_INC_STATS(net, LINUX_MIB_TCPFASTOPENBLACKHOLE);
}
@@ -508,17 +518,27 @@ void tcp_fastopen_active_disable(struct sock *sk)
bool tcp_fastopen_active_should_disable(struct sock *sk)
{
unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout;
- int tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
unsigned long timeout;
+ int tfo_da_times;
int multiplier;
+ if (!tfo_bh_timeout)
+ return false;
+
+ tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
if (!tfo_da_times)
return false;
+ /* Paired with smp_mb__before_atomic() in tcp_fastopen_active_disable() */
+ smp_rmb();
+
/* Limit timeout to max: 2^6 * initial timeout */
multiplier = 1 << min(tfo_da_times - 1, 6);
- timeout = multiplier * tfo_bh_timeout * HZ;
- if (time_before(jiffies, sock_net(sk)->ipv4.tfo_active_disable_stamp + timeout))
+
+ /* Paired with the WRITE_ONCE() in tcp_fastopen_active_disable(). */
+ timeout = READ_ONCE(sock_net(sk)->ipv4.tfo_active_disable_stamp) +
+ multiplier * tfo_bh_timeout * HZ;
+ if (time_before(jiffies, timeout))
return true;
/* Mark check bit so we can check for successful active TFO