From: Lance Richardson <lrichard@redhat•com>
To: Shmulik Ladkani <shmulik.ladkani@gmail•com>
Cc: netdev@vger•kernel.org, fw@strlen•de, jtluka@redhat•com,
hannes@stressinduktion•org
Subject: Re: [PATCH net v3] ipv4: allow local fragmentation in ip_finish_output_gso()
Date: Fri, 4 Nov 2016 09:48:02 -0400 (EDT) [thread overview]
Message-ID: <1292666010.97911366.1478267282598.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20161104112409.6277b7b0@halley>
> From: "Shmulik Ladkani" <shmulik.ladkani@gmail•com>
> To: "Lance Richardson" <lrichard@redhat•com>
> Cc: netdev@vger•kernel.org, fw@strlen•de, jtluka@redhat•com, hannes@stressinduktion•org
> Sent: Friday, November 4, 2016 5:24:09 AM
> Subject: Re: [PATCH net v3] ipv4: allow local fragmentation in ip_finish_output_gso()
>
> Hi,
>
> On Thu, 3 Nov 2016 09:06:27 -0400 (EDT) Lance Richardson
> <lrichard@redhat•com> wrote:
> > I'm not sure what could be added that would help, was there something
> > specific you had in mind?
>
> How about something like this (preliminary, feel free to massage):
>
> @@ -248,10 +248,16 @@ static int ip_finish_output_gso(struct net *net, struct
> sock *sk,
>
> /* Slowpath - GSO segment length is exceeding the dst MTU.
> *
> - * This can happen in two cases:
> - * 1) TCP GRO packet, DF bit not set
> - * 2) skb arrived via virtio-net, we thus get TSO/GSO skbs directly
> - * from host network stack.
> + * This can happen in several cases:
> + * - Forwarding of TCP GRO packet, DF bit not set
> + * - Forwarding of skb arrived in a virtualization environment (from
> + * virtio-net/vhost/tap) with TSO/GSO size set by other's network
> + * stack
> + * - Local GSO skb xmitted on an NETIF_F_TSO tunnel stacked over an
> + * interface with a smaller mtu
> + * - Arriving GRO skb (or GSO skb in a virtualized env) that gets L2
> + * bridged to a NETIF_F_TSO tunnel stacked over an interface with an
> + * insufficent mtu
> */
> features = netif_skb_features(skb);
> BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
>
Thanks, that looks good to me. I can send a follow-up patch with this change,
if you like (there seems to be agreement that the original patch is OK).
Lance
next prev parent reply other threads:[~2016-11-04 13:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 20:36 [PATCH net v3] ipv4: allow local fragmentation in ip_finish_output_gso() Lance Richardson
2016-11-03 7:42 ` Shmulik Ladkani
2016-11-03 9:44 ` Hannes Frederic Sowa
2016-11-03 13:06 ` Lance Richardson
2016-11-04 9:24 ` Shmulik Ladkani
2016-11-04 13:48 ` Lance Richardson [this message]
2016-11-03 9:42 ` Hannes Frederic Sowa
2016-11-03 20:12 ` David Miller
2016-11-03 20:40 ` Shmulik Ladkani
2016-11-03 20:56 ` David Miller
2016-11-03 20:27 ` Shmulik Ladkani
2016-11-03 21:05 ` Lance Richardson
2016-11-03 21:34 ` Hannes Frederic Sowa
2016-11-04 9:40 ` Shmulik Ladkani
2016-11-04 13:49 ` Lance Richardson
2016-11-04 8:02 ` Shmulik Ladkani
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