udp: use limited socket backlog

[ Upstream commit 55349790d7cbf0d381873a7ece1dcafcffd4aaa9 ]

Make udp adapt to the limited socket backlog change.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 22 insertions, 12 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index f0126fdd7e04..7bb45686f3c5 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1372,8 +1372,10 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
         bh_lock_sock(sk);
         if (!sock_owned_by_user(sk))
                 rc = __udp_queue_rcv_skb(sk, skb);
-        else
-                sk_add_backlog(sk, skb);
+        else if (sk_add_backlog_limited(sk, skb)) {
+                bh_unlock_sock(sk);
+                goto drop;
+        }
         bh_unlock_sock(sk);
 
         return rc;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 69ebdbe78c47..bf88ce073d26 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -584,16 +584,20 @@ static void flush_stack(struct sock **stack, unsigned int count,
                         bh_lock_sock(sk);
                         if (!sock_owned_by_user(sk))
                                 udpv6_queue_rcv_skb(sk, skb1);
-                        else
-                                sk_add_backlog(sk, skb1);
+                        else if (sk_add_backlog_limited(sk, skb1)) {
+                                kfree_skb(skb1);
+                                bh_unlock_sock(sk);
+                                goto drop;
+                        }
                         bh_unlock_sock(sk);
-                } else {
-                        atomic_inc(&sk->sk_drops);
-                        UDP6_INC_STATS_BH(sock_net(sk),
-                                        UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
-                        UDP6_INC_STATS_BH(sock_net(sk),
-                                        UDP_MIB_INERRORS, IS_UDPLITE(sk));
+                        continue;
                 }
+drop:
+                atomic_inc(&sk->sk_drops);
+                UDP6_INC_STATS_BH(sock_net(sk),
+                                UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
+                UDP6_INC_STATS_BH(sock_net(sk),
+                                UDP_MIB_INERRORS, IS_UDPLITE(sk));
         }
 }
 /*
@@ -756,8 +760,12 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
         bh_lock_sock(sk);
         if (!sock_owned_by_user(sk))
                 udpv6_queue_rcv_skb(sk, skb);
-        else
-                sk_add_backlog(sk, skb);
+        else if (sk_add_backlog_limited(sk, skb)) {
+                atomic_inc(&sk->sk_drops);
+                bh_unlock_sock(sk);
+                sock_put(sk);
+                goto discard;
+        }
         bh_unlock_sock(sk);
         sock_put(sk);
         return 0;