5 files changed, 19 insertions, 4 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a2f003239c85..ced61f87660e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -724,6 +724,10 @@ struct net_device
         /* rtnetlink link ops */
         const struct rtnl_link_ops *rtnl_link_ops;
 
+        /* for setting kernel sock attribute on TCP connection setup */
+#define GSO_MAX_SIZE            65536
+        unsigned int            gso_max_size;
+
         /* The TX queue control structures */
         unsigned int                    egress_subqueue_count;
         struct net_device_subqueue      egress_subqueue[1];
@@ -1475,6 +1479,12 @@ static inline int netif_needs_gso(struct net_device *dev, struct sk_buff *skb)
                 unlikely(skb->ip_summed != CHECKSUM_PARTIAL));
 }
 
+static inline void netif_set_gso_max_size(struct net_device *dev,
+                                          unsigned int size)
+{
+        dev->gso_max_size = size;
+}
+
 /* On bonding slaves other than the currently active slave, suppress
  * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and
  * ARP on active-backup slaves with arp_validate enabled.
diff --git a/include/net/sock.h b/include/net/sock.h
index 39112e75411c..8358fff002eb 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -151,6 +151,7 @@ struct sock_common {
   *     @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
   *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
+  *     @sk_gso_max_size: Maximum GSO segment size to build
   *     @sk_lingertime: %SO_LINGER l_linger setting
   *     @sk_backlog: always used with the per-socket spinlock held
   *     @sk_callback_lock: used with the callbacks in the end of this struct
@@ -237,6 +238,7 @@ struct sock {
         gfp_t                   sk_allocation;
         int                     sk_route_caps;
         int                     sk_gso_type;
+        unsigned int            sk_gso_max_size;
         int                     sk_rcvlowat;
         unsigned long           sk_flags;
         unsigned long           sk_lingertime;
diff --git a/net/core/dev.c b/net/core/dev.c
index fcdf03cf3b3f..f973e38b81af 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4021,6 +4021,7 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
         }
 
         dev->egress_subqueue_count = queue_count;
+        dev->gso_max_size = GSO_MAX_SIZE;
 
         dev->get_stats = internal_stats;
         netpoll_netdev_init(dev);
diff --git a/net/core/sock.c b/net/core/sock.c
index bb5236aee643..b1a6ed4d33c1 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1095,10 +1095,12 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
         if (sk->sk_route_caps & NETIF_F_GSO)
                 sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
         if (sk_can_gso(sk)) {
-                if (dst->header_len)
+                if (dst->header_len) {
                         sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
-                else
+                } else {
                         sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
+                        sk->sk_gso_max_size = dst->dev->gso_max_size;
+                }
         }
 }
 EXPORT_SYMBOL_GPL(sk_setup_caps);
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b4e11d834c9f..a627616314ba 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -998,7 +998,7 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
         xmit_size_goal = mss_now;
 
         if (doing_tso) {
-                xmit_size_goal = (65535 -
+                xmit_size_goal = ((sk->sk_gso_max_size - 1) -
                                   inet_csk(sk)->icsk_af_ops->net_header_len -
                                   inet_csk(sk)->icsk_ext_hdr_len -
                                   tp->tcp_header_len);
@@ -1282,7 +1282,7 @@ static int tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
         limit = min(send_win, cong_win);
 
         /* If a full-sized TSO skb can be sent, do it. */
-        if (limit >= 65536)
+        if (limit >= sk->sk_gso_max_size)
                 goto send_now;
 
         if (sysctl_tcp_tso_win_divisor) {