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 7EED91C6FFE; Wed, 5 Mar 2025 17:58:02 +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=1741197482; cv=none; b=igtiP+MGDaWnzUuEBrYkaX7jyDQYKpTk2+K2ZdBt3dtCZaijB8b491owuP8KcrgJWC1JSSekMf2D2veh2z+UmrEHVEf8BP/OegPvj1Ym6nJGtbiiO5ahP+YG1rGzdLyr9KENiuZOP8ovP2NGXiLJADfsY4wtUEabG+QBlj+pJK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197482; c=relaxed/simple; bh=wkOX9kpFwX3eTejX1GrPQvNoAPu1aH9n6EPfEGVZbeQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CDCgx57bw56tozpFAJVQeuJJYpWvD248YpPw2T2RXtd9iM34JmoMV2edI0vQTUjAjRB7gMwPY4huMSy9HlLwQlTO6R0mWzvA8TLac020iOXqEtAu068l+sFJlKo7L86CCsqv1oNT9qiDh73B4MZTuAFZV2WOC0w7IcTLU4DVHPU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Cl0sRdrZ; 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="Cl0sRdrZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C24DFC4CED1; Wed, 5 Mar 2025 17:58:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197482; bh=wkOX9kpFwX3eTejX1GrPQvNoAPu1aH9n6EPfEGVZbeQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cl0sRdrZEDlE/XgiJqxJo5L6451le89KrhJ2d7kJSfZKVy3Gcln6DLlyuvh6uyx7v aTLBatfVbIVXZ48GxsL3uveQttUL9YnmaN4dRg2cMEx9GTa7GSpvW/zJb8xc4/7USl j08cpG5fTtpcFrEawpTZCnxlXvz94YVCXvI5vxbg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Justin Iurman , David Lebrun , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 139/176] net: ipv6: seg6_iptunnel: mitigate 2-realloc issue Date: Wed, 5 Mar 2025 18:48:28 +0100 Message-ID: <20250305174511.024603631@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174505.437358097@linuxfoundation.org> References: <20250305174505.437358097@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Justin Iurman [ Upstream commit 40475b63761abb6f8fdef960d03228a08662c9c4 ] This patch mitigates the two-reallocations issue with seg6_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 the improvement: - before: https://ibb.co/3Cg4sNH - after: https://ibb.co/8rQ350r Signed-off-by: Justin Iurman Cc: David Lebrun Signed-off-by: Paolo Abeni Stable-dep-of: c64a0727f9b1 ("net: ipv6: fix dst ref loop on input in seg6 lwt") Signed-off-by: Sasha Levin --- net/ipv6/seg6_iptunnel.c | 85 ++++++++++++++++++++++++---------------- 1 file changed, 52 insertions(+), 33 deletions(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index ae5299c277bcf..c161298c8b335 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -124,8 +124,8 @@ static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb, return flowlabel; } -/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */ -int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) +static int __seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, + int proto, struct dst_entry *cache_dst) { struct dst_entry *dst = skb_dst(skb); struct net *net = dev_net(dst->dev); @@ -137,7 +137,7 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) hdrlen = (osrh->hdrlen + 1) << 3; tot_len = hdrlen + sizeof(*hdr); - err = skb_cow_head(skb, tot_len + skb->mac_len); + err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb)); if (unlikely(err)) return err; @@ -197,11 +197,18 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) return 0; } + +/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */ +int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) +{ + return __seg6_do_srh_encap(skb, osrh, proto, NULL); +} EXPORT_SYMBOL_GPL(seg6_do_srh_encap); /* encapsulate an IPv6 packet within an outer IPv6 header with reduced SRH */ static int seg6_do_srh_encap_red(struct sk_buff *skb, - struct ipv6_sr_hdr *osrh, int proto) + struct ipv6_sr_hdr *osrh, int proto, + struct dst_entry *cache_dst) { __u8 first_seg = osrh->first_segment; struct dst_entry *dst = skb_dst(skb); @@ -230,7 +237,7 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, tot_len = red_hdrlen + sizeof(struct ipv6hdr); - err = skb_cow_head(skb, tot_len + skb->mac_len); + err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb)); if (unlikely(err)) return err; @@ -317,8 +324,8 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, return 0; } -/* insert an SRH within an IPv6 packet, just after the IPv6 header */ -int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) +static int __seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, + struct dst_entry *cache_dst) { struct ipv6hdr *hdr, *oldhdr; struct ipv6_sr_hdr *isrh; @@ -326,7 +333,7 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) hdrlen = (osrh->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)) return err; @@ -369,9 +376,8 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) return 0; } -EXPORT_SYMBOL_GPL(seg6_do_srh_inline); -static int seg6_do_srh(struct sk_buff *skb) +static int seg6_do_srh(struct sk_buff *skb, struct dst_entry *cache_dst) { struct dst_entry *dst = skb_dst(skb); struct seg6_iptunnel_encap *tinfo; @@ -384,7 +390,7 @@ static int seg6_do_srh(struct sk_buff *skb) if (skb->protocol != htons(ETH_P_IPV6)) return -EINVAL; - err = seg6_do_srh_inline(skb, tinfo->srh); + err = __seg6_do_srh_inline(skb, tinfo->srh, cache_dst); if (err) return err; break; @@ -402,9 +408,11 @@ static int seg6_do_srh(struct sk_buff *skb) return -EINVAL; if (tinfo->mode == SEG6_IPTUN_MODE_ENCAP) - err = seg6_do_srh_encap(skb, tinfo->srh, proto); + err = __seg6_do_srh_encap(skb, tinfo->srh, + proto, cache_dst); else - err = seg6_do_srh_encap_red(skb, tinfo->srh, proto); + err = seg6_do_srh_encap_red(skb, tinfo->srh, + proto, cache_dst); if (err) return err; @@ -425,11 +433,13 @@ static int seg6_do_srh(struct sk_buff *skb) skb_push(skb, skb->mac_len); if (tinfo->mode == SEG6_IPTUN_MODE_L2ENCAP) - err = seg6_do_srh_encap(skb, tinfo->srh, - IPPROTO_ETHERNET); + err = __seg6_do_srh_encap(skb, tinfo->srh, + IPPROTO_ETHERNET, + cache_dst); else err = seg6_do_srh_encap_red(skb, tinfo->srh, - IPPROTO_ETHERNET); + IPPROTO_ETHERNET, + cache_dst); if (err) return err; @@ -444,6 +454,13 @@ static int seg6_do_srh(struct sk_buff *skb) return 0; } +/* insert an SRH within an IPv6 packet, just after the IPv6 header */ +int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) +{ + return __seg6_do_srh_inline(skb, osrh, NULL); +} +EXPORT_SYMBOL_GPL(seg6_do_srh_inline); + static int seg6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { @@ -458,14 +475,15 @@ static int seg6_input_core(struct net *net, struct sock *sk, struct seg6_lwt *slwt; int err; - err = seg6_do_srh(skb); - if (unlikely(err)) - goto drop; - slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); local_bh_disable(); dst = dst_cache_get(&slwt->cache); + local_bh_enable(); + + err = seg6_do_srh(skb, dst); + if (unlikely(err)) + goto drop; skb_dst_drop(skb); @@ -473,17 +491,18 @@ static int seg6_input_core(struct net *net, struct sock *sk, ip6_route_input(skb); dst = skb_dst(skb); if (!dst->error) { + local_bh_disable(); dst_cache_set_ip6(&slwt->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; if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, @@ -529,16 +548,16 @@ static int seg6_output_core(struct net *net, struct sock *sk, struct seg6_lwt *slwt; int err; - err = seg6_do_srh(skb); - if (unlikely(err)) - goto drop; - slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); local_bh_disable(); dst = dst_cache_get(&slwt->cache); local_bh_enable(); + err = seg6_do_srh(skb, dst); + if (unlikely(err)) + goto drop; + if (unlikely(!dst)) { struct ipv6hdr *hdr = ipv6_hdr(skb); struct flowi6 fl6; @@ -560,15 +579,15 @@ static int seg6_output_core(struct net *net, struct sock *sk, local_bh_disable(); dst_cache_set_ip6(&slwt->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; - if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb, NULL, skb_dst(skb)->dev, dst_output); -- 2.39.5