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 3D8A91C860D; Wed, 5 Mar 2025 18:00:36 +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=1741197636; cv=none; b=rRzjnb9NKZKY9f66KhGEVeApVCBSNQp+LYep0Xvox6GyO8Khcg3b6j/71FJH+kcrApld4VbmtoIKEzbvRuXWZRUaX1m/0gISIGpZBvzWJJX/hXEjrGt9uuTdnu/96zXZTng7DeQXm9babuEW+VPs2OGHiaHlmKuHagR5R6djXXM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197636; c=relaxed/simple; bh=H8a3VyebIW29XdaRiD/5eP57g/6piX3LK6KWa24yBPo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aetKIYTIzIWNJUay9EvW2YpMrxjCfMrDBWw1c1cKiPDQ7stOdP+z3C3obiwV/Pm3lmYbNN30t7TNaxKm59oLm5U8ffcAaYiVHlPGozEYFbdY1Gh6iNCx9K2FRjrr/sxzkeOUxLTxFTgSkRKVOuRhj++40MMsEw9W0ABXniah144= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sTfgsZUw; 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="sTfgsZUw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B74CCC4CED1; Wed, 5 Mar 2025 18:00:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197636; bh=H8a3VyebIW29XdaRiD/5eP57g/6piX3LK6KWa24yBPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sTfgsZUwbcL2ifasYXYajMsJwGw/5q/Iq5zedSwzAE+qadLLMAS+QEMtOaY9BKCJq hwbm2fkpXHpeCAh82uG0ejktq72FU7ttL8LYFvJ9Q4wv2RkZWbGR4ffHYIXyfsikL7 Ntpn3wvFP728dS0vQj1XbllP9w6PqcOr8VIbFWa8= 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 6.6 048/142] net: ipv6: rpl_iptunnel: mitigate 2-realloc issue Date: Wed, 5 Mar 2025 18:47:47 +0100 Message-ID: <20250305174502.268802541@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174500.327985489@linuxfoundation.org> References: <20250305174500.327985489@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 6.6-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 db3c19a42e1ca..7ba22d2f2bfef 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: @@ -262,29 +264,31 @@ 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; if (!dst) { 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_drop(skb); 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