This is a note to let you know that I've just added the patch titled ipv6: icmp6: avoid indirect call for icmpv6_send() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv6-icmp6-avoid-indirect-call-for-icmpv6_send.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From cc7a21b6fbd945f8d8f61422ccd27203c1fafeb7 Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Fri, 19 Jun 2020 12:02:59 -0700 Subject: ipv6: icmp6: avoid indirect call for icmpv6_send() From: Eric Dumazet <edumazet@xxxxxxxxxx> commit cc7a21b6fbd945f8d8f61422ccd27203c1fafeb7 upstream. If IPv6 is builtin, we do not need an expensive indirect call to reach icmp6_send(). v2: put inline keyword before the type to avoid sparse warnings. Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/icmpv6.h | 22 +++++++++++++++++++++- net/ipv6/icmp.c | 5 +++-- net/ipv6/ip6_icmp.c | 10 +++++----- 3 files changed, 29 insertions(+), 8 deletions(-) --- a/include/linux/icmpv6.h +++ b/include/linux/icmpv6.h @@ -13,12 +13,32 @@ static inline struct icmp6hdr *icmp6_hdr #include <linux/netdevice.h> #if IS_ENABLED(CONFIG_IPV6) -extern void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info); typedef void ip6_icmp_send_t(struct sk_buff *skb, u8 type, u8 code, __u32 info, const struct in6_addr *force_saddr); +#if IS_BUILTIN(CONFIG_IPV6) +void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, + const struct in6_addr *force_saddr); +static inline void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) +{ + icmp6_send(skb, type, code, info, NULL); +} +static inline int inet6_register_icmp_sender(ip6_icmp_send_t *fn) +{ + BUILD_BUG_ON(fn != icmp6_send); + return 0; +} +static inline int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn) +{ + BUILD_BUG_ON(fn != icmp6_send); + return 0; +} +#else +extern void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info); extern int inet6_register_icmp_sender(ip6_icmp_send_t *fn); extern int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn); +#endif + int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type, unsigned int data_len); --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -421,8 +421,8 @@ static int icmp6_iif(const struct sk_buf /* * Send an ICMP message in response to a packet in error */ -static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, - const struct in6_addr *force_saddr) +void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, + const struct in6_addr *force_saddr) { struct net *net = dev_net(skb->dev); struct inet6_dev *idev = NULL; @@ -596,6 +596,7 @@ out: out_bh_enable: local_bh_enable(); } +EXPORT_SYMBOL(icmp6_send); /* Slightly more convenient version of icmp6_send. */ --- a/net/ipv6/ip6_icmp.c +++ b/net/ipv6/ip6_icmp.c @@ -9,6 +9,8 @@ #if IS_ENABLED(CONFIG_IPV6) +#if !IS_BUILTIN(CONFIG_IPV6) + static ip6_icmp_send_t __rcu *ip6_icmp_send; int inet6_register_icmp_sender(ip6_icmp_send_t *fn) @@ -37,14 +39,12 @@ void icmpv6_send(struct sk_buff *skb, u8 rcu_read_lock(); send = rcu_dereference(ip6_icmp_send); - - if (!send) - goto out; - send(skb, type, code, info, NULL); -out: + if (send) + send(skb, type, code, info, NULL); rcu_read_unlock(); } EXPORT_SYMBOL(icmpv6_send); +#endif #if IS_ENABLED(CONFIG_NF_NAT) #include <net/netfilter/nf_conntrack.h> Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are queue-4.14/ipv6-icmp6-avoid-indirect-call-for-icmpv6_send.patch