From: Pavel Begunkov <asml.silence@gmail.com>
To: netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
linux-kernel@vger.kernel.org,
Pavel Begunkov <asml.silence@gmail.com>
Subject: [PATCH 01/14] ipv6: optimise dst referencing
Date: Tue, 11 Jan 2022 01:21:33 +0000 [thread overview]
Message-ID: <6ed8db52c96c8775fd311715d2b6d5e20d5dd9a5.1641863490.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1641863490.git.asml.silence@gmail.com>
__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
next prev parent reply other threads:[~2022-01-11 1:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-11 1:21 [PATCH 00/14] udp optimisation Pavel Begunkov
2022-01-11 1:21 ` Pavel Begunkov [this message]
2022-01-11 1:21 ` [PATCH 02/14] ipv6: shuffle up->pending AF_INET bits Pavel Begunkov
2022-01-11 1:21 ` [PATCH 03/14] ipv6: remove daddr temp buffer in __ip6_make_skb Pavel Begunkov
2022-01-11 1:21 ` [PATCH 04/14] ipv6: clean up cork setup/release Pavel Begunkov
2022-01-11 1:21 ` [PATCH 05/14] ipv6: don't zero cork's flowi after use Pavel Begunkov
2022-01-11 1:21 ` [PATCH 06/14] ipv6: pass full cork into __ip6_append_data() Pavel Begunkov
2022-01-11 1:21 ` [PATCH 07/14] ipv6: pass flow in ip6_make_skb together with cork Pavel Begunkov
2022-01-11 1:21 ` [PATCH 08/14] ipv6/udp: don't make extra copies of iflow Pavel Begunkov
2022-01-11 1:21 ` [PATCH 09/14] ipv6: hand dst refs to cork setup Pavel Begunkov
2022-01-11 15:39 ` Willem de Bruijn
2022-01-11 15:57 ` Pavel Begunkov
2022-01-11 17:11 ` Paolo Abeni
2022-01-11 20:39 ` Pavel Begunkov
2022-01-12 11:15 ` Paolo Abeni
2022-01-12 16:49 ` Pavel Begunkov
2022-01-11 1:21 ` [PATCH 10/14] skbuff: drop zero check from skb_zcopy_set Pavel Begunkov
2022-01-11 1:21 ` [PATCH 11/14] skbuff: drop null check from skb_zcopy Pavel Begunkov
2022-01-11 1:21 ` [PATCH 12/14] skbuff: optimise alloc_skb_with_frags() Pavel Begunkov
2022-01-11 1:21 ` [PATCH 13/14] net: inline part of skb_csum_hwoffload_help Pavel Begunkov
2022-01-11 9:24 ` David Laight
2022-01-11 16:59 ` Pavel Begunkov
2022-01-11 17:25 ` David Laight
2022-01-11 20:48 ` Pavel Begunkov
2022-01-12 2:41 ` David Laight
2022-01-12 16:43 ` Pavel Begunkov
2022-01-11 1:21 ` [PATCH 14/14] net: inline sock_alloc_send_skb Pavel Begunkov
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