From: Zhu Yi <yi.zhu@intel.com>

BugLink: http://bugs.launchpad.net/bugs/807462

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>
(cherry picked from commit 55349790d7cbf0d381873a7ece1dcafcffd4aaa9)

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
net/ipv4/udp.c | 6 ++++--
net/ipv6/udp.c | 28 ++++++++++++++++++----------
2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 6aa6c1c..1e88bac 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1161,8 +1161,10 @@ 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 8af66ad..1748815 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -455,16 +455,20 @@ 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));
}
}
/*
@@ -627,8 +631,12 @@ 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;
--
1.7.4.1


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