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 911F51E378C; Wed, 19 Feb 2025 08:54:20 +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=1739955260; cv=none; b=qaKJ5hd0btGNNUQ6XDXipAeOnWYqBcgdAcjEYtcE8e+wj1ocXQK7vIikW7DB4Yvxrwry6PdlxsJ+3r02SDgUGJYyJorUz2gcxXiXZ3t/2FDwTBwWNEfIIbE2TR78cbOgqVqD416Lr0WqFUziy91/gb8YdLaqYbiyypQdxT/Ko5M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739955260; c=relaxed/simple; bh=R63+F9GsSdCnh/jF1XCI0MMtNmllJwjWgGXmkeXfKBg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Iti+2amWwz2xtL/Dw11cwirAvuhZQjRI++eP5F3HEW0uxjvHJ7qc+YwmUx+HSGaeobhW8+rIOYzRT6x1N3/BU3X6CvtZH8vArf2deOs2+JjWzt3+gH7fSAc2Geo9mmxU7Ea0oqq/LPD6IDAcwMYcUbUV8iIVwuclYHLSiFabfJo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=l9Oy1NxY; 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="l9Oy1NxY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10EDCC4CEE6; Wed, 19 Feb 2025 08:54:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739955260; bh=R63+F9GsSdCnh/jF1XCI0MMtNmllJwjWgGXmkeXfKBg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l9Oy1NxYm3UmHhQNTSfDOei52qOxFVIXodpcW+XvkVexJ+2UmEZ/H34+K6PgKicff 1435W9BdJjOlJjYYR03pJLuuB4Z1r9P5OJ0jLg3CsD3ftGnHVaqTktQsEz05uhjaoG yRviNpDqoI7MiV/1bjvJnN8jyLAu/vFHT9wfl0d4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Justin Iurman , Paolo Abeni , Sasha Levin Subject: [PATCH 6.12 164/230] net: ipv6: ioam6_iptunnel: mitigate 2-realloc issue Date: Wed, 19 Feb 2025 09:28:01 +0100 Message-ID: <20250219082608.114537407@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082601.683263930@linuxfoundation.org> References: <20250219082601.683263930@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Justin Iurman [ Upstream commit dce525185bc92864e5a318040285ee070563fe34 ] This patch mitigates the two-reallocations issue with ioam6_iptunnel by providing the dst_entry (in the cache) to the first call to skb_cow_head(). As a result, the very first iteration may 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: - inline mode: - before: https://ibb.co/LhQ8V63 - after: https://ibb.co/x5YT2bS - encap mode: - before: https://ibb.co/3Cjm5m0 - after: https://ibb.co/TwpsxTC - encap mode with tunsrc: - before: https://ibb.co/Gpy9QPg - after: https://ibb.co/PW1bZFT This patch also fixes an incorrect behavior: after the insertion, the second call to skb_cow_head() makes sure that the dev has enough headroom in the skb for layer 2 and stuff. In that case, the "old" dst_entry was used, which is now fixed. After discussing with Paolo, it appears that both patches can be merged into a single one -this one- (for the sake of readability) and target net-next. Signed-off-by: Justin Iurman Signed-off-by: Paolo Abeni Stable-dep-of: 92191dd10730 ("net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels") Signed-off-by: Sasha Levin --- net/ipv6/ioam6_iptunnel.c | 73 ++++++++++++++++++++------------------- 1 file changed, 37 insertions(+), 36 deletions(-) diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c index beb6b4cfc551c..e81b45b1f6555 100644 --- a/net/ipv6/ioam6_iptunnel.c +++ b/net/ipv6/ioam6_iptunnel.c @@ -255,14 +255,15 @@ static int ioam6_do_fill(struct net *net, struct sk_buff *skb) } static int ioam6_do_inline(struct net *net, struct sk_buff *skb, - struct ioam6_lwt_encap *tuninfo) + struct ioam6_lwt_encap *tuninfo, + struct dst_entry *cache_dst) { struct ipv6hdr *oldhdr, *hdr; int hdrlen, err; hdrlen = (tuninfo->eh.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; @@ -293,7 +294,8 @@ static int ioam6_do_encap(struct net *net, struct sk_buff *skb, struct ioam6_lwt_encap *tuninfo, bool has_tunsrc, struct in6_addr *tunsrc, - struct in6_addr *tundst) + struct in6_addr *tundst, + struct dst_entry *cache_dst) { struct dst_entry *dst = skb_dst(skb); struct ipv6hdr *hdr, *inner_hdr; @@ -302,7 +304,7 @@ static int ioam6_do_encap(struct net *net, struct sk_buff *skb, hdrlen = (tuninfo->eh.hdrlen + 1) << 3; len = sizeof(*hdr) + hdrlen; - err = skb_cow_head(skb, len + skb->mac_len); + err = skb_cow_head(skb, len + dst_dev_overhead(cache_dst, skb)); if (unlikely(err)) return err; @@ -336,7 +338,7 @@ static int ioam6_do_encap(struct net *net, struct sk_buff *skb, static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) { - struct dst_entry *dst = skb_dst(skb); + struct dst_entry *dst = skb_dst(skb), *cache_dst; struct in6_addr orig_daddr; struct ioam6_lwt *ilwt; int err = -EINVAL; @@ -354,6 +356,10 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) orig_daddr = ipv6_hdr(skb)->daddr; + local_bh_disable(); + cache_dst = dst_cache_get(&ilwt->cache); + local_bh_enable(); + switch (ilwt->mode) { case IOAM6_IPTUNNEL_MODE_INLINE: do_inline: @@ -361,7 +367,7 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) if (ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP) goto out; - err = ioam6_do_inline(net, skb, &ilwt->tuninfo); + err = ioam6_do_inline(net, skb, &ilwt->tuninfo, cache_dst); if (unlikely(err)) goto drop; @@ -371,7 +377,7 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) /* Encapsulation (ip6ip6) */ err = ioam6_do_encap(net, skb, &ilwt->tuninfo, ilwt->has_tunsrc, &ilwt->tunsrc, - &ilwt->tundst); + &ilwt->tundst, cache_dst); if (unlikely(err)) goto drop; @@ -389,41 +395,36 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) goto drop; } - err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); - if (unlikely(err)) - goto drop; + if (unlikely(!cache_dst)) { + struct ipv6hdr *hdr = ipv6_hdr(skb); + struct flowi6 fl6; + + memset(&fl6, 0, sizeof(fl6)); + fl6.daddr = hdr->daddr; + fl6.saddr = hdr->saddr; + fl6.flowlabel = ip6_flowinfo(hdr); + fl6.flowi6_mark = skb->mark; + fl6.flowi6_proto = hdr->nexthdr; + + cache_dst = ip6_route_output(net, NULL, &fl6); + if (cache_dst->error) { + err = cache_dst->error; + dst_release(cache_dst); + goto drop; + } - if (!ipv6_addr_equal(&orig_daddr, &ipv6_hdr(skb)->daddr)) { local_bh_disable(); - dst = dst_cache_get(&ilwt->cache); + dst_cache_set_ip6(&ilwt->cache, cache_dst, &fl6.saddr); local_bh_enable(); - if (unlikely(!dst)) { - struct ipv6hdr *hdr = ipv6_hdr(skb); - struct flowi6 fl6; - - memset(&fl6, 0, sizeof(fl6)); - fl6.daddr = hdr->daddr; - fl6.saddr = hdr->saddr; - fl6.flowlabel = ip6_flowinfo(hdr); - fl6.flowi6_mark = skb->mark; - fl6.flowi6_proto = hdr->nexthdr; - - dst = ip6_route_output(net, NULL, &fl6); - if (dst->error) { - err = dst->error; - dst_release(dst); - goto drop; - } - - local_bh_disable(); - dst_cache_set_ip6(&ilwt->cache, dst, &fl6.saddr); - local_bh_enable(); - } + err = skb_cow_head(skb, LL_RESERVED_SPACE(cache_dst->dev)); + if (unlikely(err)) + goto drop; + } + if (!ipv6_addr_equal(&orig_daddr, &ipv6_hdr(skb)->daddr)) { skb_dst_drop(skb); - skb_dst_set(skb, dst); - + skb_dst_set(skb, cache_dst); return dst_output(net, sk, skb); } out: -- 2.39.5