Messages in this thread Patch in this message | | | From | Pavel Begunkov <> | Subject | [PATCH 01/14] ipv6: optimise dst referencing | Date | Tue, 11 Jan 2022 01:21:33 +0000 |
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__ip6_make_skb() initialises skb's dst by taking an additional reference to cork->dst. However, cork->dst comes into the function holding a ref, which will be put shortly at the end of the function in ip6_cork_release().
Avoid this extra pair of get/put atomics by stealing cork->dst and NULL'ing the field, ip6_cork_release() already handles zero values.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- net/ipv6/ip6_output.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
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)); -- 2.34.1
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