From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E4E8F1CAA8F; Tue, 11 Mar 2025 15:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741707372; cv=none; b=MV4rWoezWarUyzfLZVYPlOEovRiGskTHdRGpIub8Bhm7jMbFie7gZZO/EGeeCIussKnrjJLxFxtkeOZ50nc9yzMDBvjI2ePHziR9MnnOVnPPxSqe4maPY8IEzni/x0NfVUJecBiOzsN971XXAop/aA3EO6TkRizPQaiXUMrZA4I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741707372; c=relaxed/simple; bh=3PgMU6M47DdKTZqW7zj1/+bS/sDa7dfpEz2+Zw8dy38=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PQ/ccsGrq4cU6g8hzZ3wDmQiTamVsWGM72c1+ngAornOD90NTOgYpQvSyDpHkk8fyLDSy38C7EwBonoSLENW1tXzmXfxtzNzxFjxUU0X0zC5mxfOfGKx3CeRLm97J0amx3pJMb375xG5X8Chi5HhvzqvejGF1xki2bqbfnflr24= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KMdLgT42; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KMdLgT42" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CA19C4CEE9; Tue, 11 Mar 2025 15:36:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741707371; bh=3PgMU6M47DdKTZqW7zj1/+bS/sDa7dfpEz2+Zw8dy38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KMdLgT426M4PRP3qtjh5ahszqeacSkOnqkh/W4VIWooOj/T0OEg2t5ZbOS8Ly9Tl0 EuhEVQshijf71WIgjrGw6Fbx5jeTFTQsGmm3+KUscQ2iFvwFMiLemIud/ZCEitE7tT lHltG4QLv786mWjSfoqUiFaYB5eSUYe46z1QP/BE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Justin Iurman , Alexander Aring , Paolo Abeni , Sasha Levin Subject: [PATCH 5.10 366/462] net: ipv6: rpl_iptunnel: mitigate 2-realloc issue Date: Tue, 11 Mar 2025 16:00:32 +0100 Message-ID: <20250311145812.808803587@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145758.343076290@linuxfoundation.org> References: <20250311145758.343076290@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Justin Iurman [ Upstream commit 985ec6f5e6235242191370628acb73d7a9f0c0ea ] This patch mitigates the two-reallocations issue with rpl_iptunnel by providing the dst_entry (in the cache) to the first call to skb_cow_head(). As a result, the very first iteration would still trigger two reallocations (i.e., empty cache), while next iterations would only trigger a single reallocation. Performance tests before/after applying this patch, which clearly shows there is no impact (it even shows improvement): - before: https://ibb.co/nQJhqwc - after: https://ibb.co/4ZvW6wV Signed-off-by: Justin Iurman Cc: Alexander Aring Signed-off-by: Paolo Abeni Stable-dep-of: 13e55fbaec17 ("net: ipv6: fix dst ref loop on input in rpl lwt") Signed-off-by: Sasha Levin --- net/ipv6/rpl_iptunnel.c | 46 ++++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 21 deletions(-) diff --git a/net/ipv6/rpl_iptunnel.c b/net/ipv6/rpl_iptunnel.c index df835dfcc5b70..dbdfdd2e52784 100644 --- a/net/ipv6/rpl_iptunnel.c +++ b/net/ipv6/rpl_iptunnel.c @@ -125,7 +125,8 @@ static void rpl_destroy_state(struct lwtunnel_state *lwt) } static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt, - const struct ipv6_rpl_sr_hdr *srh) + const struct ipv6_rpl_sr_hdr *srh, + struct dst_entry *cache_dst) { struct ipv6_rpl_sr_hdr *isrh, *csrh; const struct ipv6hdr *oldhdr; @@ -153,7 +154,7 @@ static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt, hdrlen = ((csrh->hdrlen + 1) << 3); - err = skb_cow_head(skb, hdrlen + skb->mac_len); + err = skb_cow_head(skb, hdrlen + dst_dev_overhead(cache_dst, skb)); if (unlikely(err)) { kfree(buf); return err; @@ -186,7 +187,8 @@ static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt, return 0; } -static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt) +static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt, + struct dst_entry *cache_dst) { struct dst_entry *dst = skb_dst(skb); struct rpl_iptunnel_encap *tinfo; @@ -196,7 +198,7 @@ static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt) tinfo = rpl_encap_lwtunnel(dst->lwtstate); - return rpl_do_srh_inline(skb, rlwt, tinfo->srh); + return rpl_do_srh_inline(skb, rlwt, tinfo->srh, cache_dst); } static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb) @@ -208,14 +210,14 @@ static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb) rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate); - err = rpl_do_srh(skb, rlwt); - if (unlikely(err)) - goto drop; - local_bh_disable(); dst = dst_cache_get(&rlwt->cache); local_bh_enable(); + err = rpl_do_srh(skb, rlwt, dst); + if (unlikely(err)) + goto drop; + if (unlikely(!dst)) { struct ipv6hdr *hdr = ipv6_hdr(skb); struct flowi6 fl6; @@ -237,15 +239,15 @@ static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb) local_bh_disable(); dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr); local_bh_enable(); + + err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + goto drop; } skb_dst_drop(skb); skb_dst_set(skb, dst); - err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); - if (unlikely(err)) - goto drop; - return dst_output(net, sk, skb); drop: @@ -262,12 +264,13 @@ static int rpl_input(struct sk_buff *skb) rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate); - err = rpl_do_srh(skb, rlwt); - if (unlikely(err)) - goto drop; - local_bh_disable(); dst = dst_cache_get(&rlwt->cache); + local_bh_enable(); + + err = rpl_do_srh(skb, rlwt, dst); + if (unlikely(err)) + goto drop; skb_dst_drop(skb); @@ -275,17 +278,18 @@ static int rpl_input(struct sk_buff *skb) ip6_route_input(skb); dst = skb_dst(skb); if (!dst->error) { + local_bh_disable(); dst_cache_set_ip6(&rlwt->cache, dst, &ipv6_hdr(skb)->saddr); + local_bh_enable(); } + + err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + goto drop; } else { skb_dst_set(skb, dst); } - local_bh_enable(); - - err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); - if (unlikely(err)) - goto drop; return dst_input(skb); -- 2.39.5