From cd3c748077365dde89f2a3da738ce556fd04b0a3 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 27 Jan 2022 00:36:22 +0000 Subject: ipv6: optimise dst refcounting on skb init __ip6_make_skb() gets a cork->dst ref, hands it over to skb and shortly after puts cork->dst. Save two atomics by stealing it without extra referencing, ip6_cork_release() handles NULL cork->dst. Signed-off-by: Pavel Begunkov Reviewed-by: Willem de Bruijn Signed-off-by: Jakub Kicinski --- net/ipv6/ip6_output.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 2995f8d89e7e..14d607ccfeea 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1807,6 +1807,15 @@ int ip6_append_data(struct sock *sk, } EXPORT_SYMBOL_GPL(ip6_append_data); +static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork) +{ + struct dst_entry *dst = cork->base.dst; + + cork->base.dst = NULL; + cork->base.flags &= ~IPCORK_ALLFRAG; + skb_dst_set(skb, dst); +} + static void ip6_cork_release(struct inet_cork_full *cork, struct inet6_cork *v6_cork) { @@ -1889,7 +1898,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk, skb->tstamp = cork->base.transmit_time; - skb_dst_set(skb, dst_clone(&rt->dst)); + ip6_cork_steal_dst(skb, cork); IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len); if (proto == IPPROTO_ICMPV6) { struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb)); -- cgit v1.2.3