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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a27b9c0e27c0..c71d49ce0c93 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -128,6 +128,23 @@ int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
#define REXMIT_LOST 1 /* retransmit packets marked lost */
#define REXMIT_NEW 2 /* FRTO-style transmit of unsent/new packets */
+static void tcp_gro_dev_warn(struct sock *sk, const struct sk_buff *skb)
+{
+ static bool __once __read_mostly;
+
+ if (!__once) {
+ struct net_device *dev;
+
+ __once = true;
+
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
+ pr_warn("%s: Driver has suspect GRO implementation, TCP performance may be compromised.\n",
+ dev ? dev->name : "Unknown driver");
+ rcu_read_unlock();
+ }
+}
+
/* Adapt the MSS value used to make delayed ack decision to the
* real world.
*/
@@ -144,7 +161,10 @@ static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb)
*/
len = skb_shinfo(skb)->gso_size ? : skb->len;
if (len >= icsk->icsk_ack.rcv_mss) {
- icsk->icsk_ack.rcv_mss = len;
+ icsk->icsk_ack.rcv_mss = min_t(unsigned int, len,
+ tcp_sk(sk)->advmss);
+ if (unlikely(icsk->icsk_ack.rcv_mss != len))
+ tcp_gro_dev_warn(sk, skb);
} else {
/* Otherwise, we make more careful check taking into account,
* that SACKs block is variable.