[RFC PATCH 03/11] udp: do not touch socket refcount in early demux
From: Paolo Abeni <pabeni@redhat.com>
Date: 2017-09-22 21:07:02
Subsystem:
networking [general], the rest, user datagram protocol (udp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn
use noref sockets instead. This gives some small performance improvements and will allow efficient early demux for unconnected sockets in a later patch. Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/ipv4/udp.c | 18 ++++++++++-------- net/ipv6/udp.c | 10 ++++++---- 2 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 784ced0b9150..ba49d5aa9f09 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c@@ -2050,12 +2050,13 @@ static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh, int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, int proto) { - struct sock *sk; - struct udphdr *uh; - unsigned short ulen; + struct net *net = dev_net(skb->dev); struct rtable *rt = skb_rtable(skb); + unsigned short ulen; __be32 saddr, daddr; - struct net *net = dev_net(skb->dev); + struct udphdr *uh; + struct sock *sk; + bool noref_sk; /* * Validate the packet.
@@ -2081,6 +2082,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, if (udp4_csum_init(skb, uh, proto)) goto csum_error; + noref_sk = skb_has_noref_sk(skb); sk = skb_steal_sock(skb); if (sk) { struct dst_entry *dst = skb_dst(skb);
@@ -2090,7 +2092,8 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, udp_sk_rx_dst_set(sk, dst); ret = udp_queue_rcv_skb(sk, skb); - sock_put(sk); + if (!noref_sk) + sock_put(sk); /* a return value > 0 means to resubmit the input, but * it wants the return to be -protocol, or 0 */
@@ -2261,11 +2264,10 @@ void udp_v4_early_demux(struct sk_buff *skb) uh->source, iph->saddr, dif, sdif); } - if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt)) + if (!sk) return; - skb->sk = sk; - skb->destructor = sock_efree; + skb_set_noref_sk(skb, sk); dst = READ_ONCE(sk->sk_rx_dst); if (dst)
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e2ecfb137297..8f62392c4c35 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c@@ -787,6 +787,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, struct net *net = dev_net(skb->dev); struct udphdr *uh; struct sock *sk; + bool noref_sk; u32 ulen = 0; if (!pskb_may_pull(skb, sizeof(struct udphdr)))
@@ -823,6 +824,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, goto csum_error; /* Check if the socket is already available, e.g. due to early demux */ + noref_sk = skb_has_noref_sk(skb); sk = skb_steal_sock(skb); if (sk) { struct dst_entry *dst = skb_dst(skb);
@@ -832,7 +834,8 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, udp6_sk_rx_dst_set(sk, dst); ret = udpv6_queue_rcv_skb(sk, skb); - sock_put(sk); + if (!noref_sk) + sock_put(sk); /* a return value > 0 means to resubmit the input */ if (ret > 0)
@@ -948,11 +951,10 @@ static void udp_v6_early_demux(struct sk_buff *skb) else return; - if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt)) + if (!sk) return; - skb->sk = sk; - skb->destructor = sock_efree; + skb_set_noref_sk(skb, sk); dst = READ_ONCE(sk->sk_rx_dst); if (dst)
--
2.13.5