diff mbox series

[v3,net-next,2/3] ipv6: refactor ip6_finish_output for GSO handling

Message ID 496ccff707e16e98163d2a3fbcfbc1f824fd8ec3.1697779681.git.yan@cloudflare.com
State New
Headers
Series ipv6: avoid atomic fragment on GSO output |

Commit Message

Yan Zhai Oct. 20, 2023, 5:32 a.m. UTC 
  Separate GSO and non-GSO packets handling to make the logic cleaner. For
GSO packets, frag_max_size check can be omitted because it is only
useful for packets defragmented by netfilter hooks. Both local output
and GRO logic won't produce GSO packets when defragment is needed. This
also mirrors what IPv4 side code is doing.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Yan Zhai <yan@cloudflare.com>
---
 net/ipv6/ip6_output.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

Comments

Willem de Bruijn Oct. 20, 2023, 7:16 p.m. UTC | #1 
Yan Zhai wrote:
> Separate GSO and non-GSO packets handling to make the logic cleaner. For
> GSO packets, frag_max_size check can be omitted because it is only
> useful for packets defragmented by netfilter hooks. Both local output
> and GRO logic won't produce GSO packets when defragment is needed. This
> also mirrors what IPv4 side code is doing.
> 
> Suggested-by: Florian Westphal <fw@strlen.de>
> Signed-off-by: Yan Zhai <yan@cloudflare.com>

Reviewed-by: Willem de Bruijn <willemb@google.com>

Thanks for splitting up the series. This change alone is subtle enough
that it benefits from standing alone. I thought it was intended to be
a NOOP, but you indeed call out the frag_max_size special case.
diff mbox series

Patch

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index ae87a3817d4a..3270d56b5c37 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -170,6 +170,16 @@  ip6_finish_output_gso_slowpath_drop(struct net *net, struct sock *sk,
 	return ret;
 }
 
+static int ip6_finish_output_gso(struct net *net, struct sock *sk,
+				 struct sk_buff *skb, unsigned int mtu)
+{
+	if (!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
+	    !skb_gso_validate_network_len(skb, mtu))
+		return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
+
+	return ip6_finish_output2(net, sk, skb);
+}
+
 static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	unsigned int mtu;
@@ -183,16 +193,14 @@  static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff
 #endif
 
 	mtu = ip6_skb_dst_mtu(skb);
-	if (skb_is_gso(skb) &&
-	    !(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
-	    !skb_gso_validate_network_len(skb, mtu))
-		return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
+	if (skb_is_gso(skb))
+		return ip6_finish_output_gso(net, sk, skb, mtu);
 
-	if ((skb->len > mtu && !skb_is_gso(skb)) ||
+	if (skb->len > mtu ||
 	    (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
 		return ip6_fragment(net, sk, skb, ip6_finish_output2);
-	else
-		return ip6_finish_output2(net, sk, skb);
+
+	return ip6_finish_output2(net, sk, skb);
 }
 
 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)