diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2017-01-09 16:04:14 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-01-09 21:49:12 +0100 |
| commit | 7ba91ecb16824f74ba4fcbc4e88cd4d24a839b25 (patch) | |
| tree | 23bd866126b5115cf4a14541f7700117a38efc29 /net/ipv6/icmp.c | |
| parent | net: reduce cycles spend on ICMP replies that gets rate limited (diff) | |
| download | linux-7ba91ecb16824f74ba4fcbc4e88cd4d24a839b25.tar.xz linux-7ba91ecb16824f74ba4fcbc4e88cd4d24a839b25.zip | |
net: for rate-limited ICMP replies save one atomic operation
It is possible to avoid the atomic operation in icmp{v6,}_xmit_lock,
by checking the sysctl_icmp_msgs_per_sec ratelimit before these calls,
as pointed out by Eric Dumazet, but the BH disabled state must be correct.
The icmp_global_allow() call states it must be called with BH
disabled. This protection was given by the calls icmp_xmit_lock and
icmpv6_xmit_lock. Thus, split out local_bh_disable/enable from these
functions and maintain it explicitly at callers.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/icmp.c')
| -rw-r--r-- | net/ipv6/icmp.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index b26ae8b5c1ce..230b5aac9f03 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -110,19 +110,17 @@ static const struct inet6_protocol icmpv6_protocol = { .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, }; +/* Called with BH disabled */ static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) { struct sock *sk; - local_bh_disable(); - sk = icmpv6_sk(net); if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { /* This can happen if the output path (f.e. SIT or * ip6ip6 tunnel) signals dst_link_failure() for an * outgoing ICMP6 packet. */ - local_bh_enable(); return NULL; } return sk; @@ -130,7 +128,7 @@ static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) static __inline__ void icmpv6_xmit_unlock(struct sock *sk) { - spin_unlock_bh(&sk->sk_lock.slock); + spin_unlock(&sk->sk_lock.slock); } /* @@ -489,6 +487,13 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, return; } + /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ + local_bh_disable(); + + /* Check global sysctl_icmp_msgs_per_sec ratelimit */ + if (!icmpv6_global_allow(type)) + goto out_bh_enable; + mip6_addr_swap(skb); memset(&fl6, 0, sizeof(fl6)); @@ -507,10 +512,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, sk = icmpv6_xmit_lock(net); if (!sk) - return; - - if (!icmpv6_global_allow(type)) - goto out; + goto out_bh_enable; sk->sk_mark = mark; np = inet6_sk(sk); @@ -571,6 +573,8 @@ out_dst_release: dst_release(dst); out: icmpv6_xmit_unlock(sk); +out_bh_enable: + local_bh_enable(); } /* Slightly more convenient version of icmp6_send. @@ -684,9 +688,10 @@ static void icmpv6_echo_reply(struct sk_buff *skb) fl6.flowi6_uid = sock_net_uid(net, NULL); security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); + local_bh_disable(); sk = icmpv6_xmit_lock(net); if (!sk) - return; + goto out_bh_enable; sk->sk_mark = mark; np = inet6_sk(sk); @@ -728,6 +733,8 @@ static void icmpv6_echo_reply(struct sk_buff *skb) dst_release(dst); out: icmpv6_xmit_unlock(sk); +out_bh_enable: + local_bh_enable(); } void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) |