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authorPavel Begunkov <asml.silence@gmail.com>2022-01-27 03:36:22 +0300
committerJakub Kicinski <kuba@kernel.org>2022-01-28 06:46:10 +0300
commitcd3c748077365dde89f2a3da738ce556fd04b0a3 (patch)
tree53cded77bfc603a21aa8008e2b0a0afade5dcb69 /net/ipv6/ip6_output.c
parentd344e55356c2ce883a764bb2324fd635c5af3f50 (diff)
downloadlinux-cd3c748077365dde89f2a3da738ce556fd04b0a3.tar.xz
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 <asml.silence@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6/ip6_output.c')
-rw-r--r--net/ipv6/ip6_output.c11
1 files changed, 10 insertions, 1 deletions
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));