From patchwork Tue Jan 11 01:21:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 12709376 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD802C433EF for ; Tue, 11 Jan 2022 01:24:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346216AbiAKBYs (ORCPT ); Mon, 10 Jan 2022 20:24:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346209AbiAKBYq (ORCPT ); Mon, 10 Jan 2022 20:24:46 -0500 Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [IPv6:2a00:1450:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B915C06173F; Mon, 10 Jan 2022 17:24:46 -0800 (PST) Received: by mail-wm1-x335.google.com with SMTP id d18-20020a05600c251200b0034974323cfaso490517wma.4; Mon, 10 Jan 2022 17:24:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=tq/iukreOG79JdYNe8HVV6T7x3H7rgMjUtsugvlEjlE=; b=pH6t7FlwLfwvt95KSgS+H8thrkFdfgDt4OTXvQAzPe6vleFfa/aF5R6Ief3Yqq5DN6 xb73XSqyFVZhfXNoZjud0iQ/IP9AOr04imo8r9GpXKDWUlgL7PQVxU/O4XbaQwCMx0q7 AZ53bEGEq7xZncNe6xK5DFpK1NJ2t8HKM/Jl22GAzx5w1CmS9bqwXMfEVqrmei+CuSnN s3A9FzwWpbn6iLQBE5HV4F/lzOA1ZXH2p9mZh6xkI45a0i2Z90YlEzoko8yXnbsv/9Ek a1G/w3Ee3AHX8kJ3k+pAVGlcTgLA/bF5u+bITNp1h0upctMvPyyy2rc8eWvhorkQm2Be 1FnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=tq/iukreOG79JdYNe8HVV6T7x3H7rgMjUtsugvlEjlE=; b=j8IAwEz6MucwbEtnNRLuYnt6Q7Pj5rD3j3QBJbOodlYOQkM7/3Ry3I0dnlo7haLMaV 8PX4VQ2m7sDxSVDF7TDrjuPzoJ+6IENITCOdYMhJm8Q0De3EhHgAyqEFSTJRqyUblJxv qWDBFaCmKOo5yczRTiZbrxxYERfLX3kreU5EzTxu4K9eunpSKshMlwz/zFcv5QRY+kD2 3K14CsdmubH1iharDyjKMmNpN3F5mJqM3ng8vKZTu2q+BCy7UNJHtNxA4hPdfORBdLVZ VwtXY+mN77sWpR3QwOjtvR2zOdHNp6MYt/qDGsBqXjrL9mf5Nfm6YpUSY0XqOUqCrZ7i 5i9g== X-Gm-Message-State: AOAM532FfyF+mtSh2ZfTCPbtKebXSTi/CtyCoBsQVN/Ojo+IISG2wEQK F1pFpm2NM/ZaM8bBvo5Et9z9CpsaBNc= X-Google-Smtp-Source: ABdhPJwBq/cSc1x977yGly5mi7ozjF+H29JNvFK1yuBmYkHAPR/OP//iPlqYtFeqdFU5zOMvlbraZQ== X-Received: by 2002:a7b:c449:: with SMTP id l9mr336355wmi.160.1641864284825; Mon, 10 Jan 2022 17:24:44 -0800 (PST) Received: from 127.0.0.1localhost ([148.252.129.73]) by smtp.gmail.com with ESMTPSA id i8sm709886wru.26.2022.01.10.17.24.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jan 2022 17:24:44 -0800 (PST) From: Pavel Begunkov To: netdev@vger.kernel.org, "David S . Miller" , Jakub Kicinski Cc: Hideaki YOSHIFUJI , David Ahern , Eric Dumazet , Willem de Bruijn , linux-kernel@vger.kernel.org, Pavel Begunkov Subject: [PATCH 01/14] ipv6: optimise dst referencing Date: Tue, 11 Jan 2022 01:21:33 +0000 Message-Id: <6ed8db52c96c8775fd311715d2b6d5e20d5dd9a5.1641863490.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org __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 --- 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));