From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: regression caused by 1d2024f61ec14bdb0c57a97a3fe73685abc2d198?
Date: Wed, 06 Feb 2013 09:42:45 -0800
Message-ID: <1360172565.28557.44.camel@edumazet-glaptop>
References: <20130206114321.GA13497@redhat.com>
	 <1360156059.28557.28.camel@edumazet-glaptop>
	 <20130206155049.GB14735@redhat.com>
	 <1360167332.28557.36.camel@edumazet-glaptop>
	 <20130206174228.GA16991@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Cc: alexander.h.duyck@intel.com, stephen.s.ko@intel.com,
	jeffrey.t.kirsher@intel.com, David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, sony.chacko@qlogic.com, mchan@broadcom.com,
	jitendra.kalsaria@qlogic.com, eilong@broadcom.com
To: "Michael S. Tsirkin" <mst@redhat.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-pa0-f48.google.com ([209.85.220.48]:41723 "EHLO
	mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755392Ab3BFRms (ORCPT
	<rfc822;netdev@vger.kernel.org>); Wed, 6 Feb 2013 12:42:48 -0500
Received: by mail-pa0-f48.google.com with SMTP id hz10so943579pad.21
        for <netdev@vger.kernel.org>; Wed, 06 Feb 2013 09:42:48 -0800 (PST)
In-Reply-To: <20130206174228.GA16991@redhat.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Wed, 2013-02-06 at 19:42 +0200, Michael S. Tsirkin wrote:
> On Wed, Feb 06, 2013 at 08:15:32AM -0800, Eric Dumazet wrote:
> > On Wed, 2013-02-06 at 17:50 +0200, Michael S. Tsirkin wrote:
> > 
> > > Also, I'm not sure I understand when should drivers set gso size
> > > for incoming messages and what is a reasonable value.
> > > Commit log talks about improved performance for lossy connections,
> > > in this case, isn't this something net core should set?
> > > 
> > > I see 3 in-tree drivers that do this:
> > > 
> > > drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c:                skb_shinfo(skb)->gso_size = bnx2x
> > 
> > bnx2x is fine, take a look at lines 464
> 
> Is this what you mean?
> 
>         /* This is needed in order to enable forwarding support */
>         if (frag_size) {
>                 skb_shinfo(skb)->gso_size = bnx2x_set_lro_mss(bp,
>                                         tpa_info->parsing_flags, len_on_bd);
> 
>                 /* set for GRO */
>                 if (fp->mode == TPA_MODE_GRO)
>                         skb_shinfo(skb)->gso_type =
>                             (GET_FLAG(tpa_info->parsing_flags,
>                                       PARSING_FLAGS_OVER_ETHERNET_PROTOCOL) ==
>                                                 PRS_FLAG_OVERETH_IPV6) ?
>                                 SKB_GSO_TCPV6 : SKB_GSO_TCPV4;
>         }
> 
> 
> I see it sets gso_type but apparently only if mode is GRO?
> Will this still break if mode is set to LRO?
> 
> 


In net-next tree, line 464 looks like :

static void bnx2x_set_gro_params(struct sk_buff *skb, u16 parsing_flags,
                                 u16 len_on_bd, unsigned int pkt_len)
{
        /* TPA aggregation won't have either IP options or TCP options
         * other than timestamp or IPv6 extension headers.
         */
        u16 hdrs_len = ETH_HLEN + sizeof(struct tcphdr);

        if (GET_FLAG(parsing_flags, PARSING_FLAGS_OVER_ETHERNET_PROTOCOL) ==
            PRS_FLAG_OVERETH_IPV6) {
                hdrs_len += sizeof(struct ipv6hdr);
<HERE>          skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
        } else {
                hdrs_len += sizeof(struct iphdr);
<HERE>          skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
        }

        /* Check if there was a TCP timestamp, if there is it's will
         * always be 12 bytes length: nop nop kind length echo val.
         *
         * Otherwise FW would close the aggregation.
         */
        if (parsing_flags & PARSING_FLAGS_TIME_STAMP_EXIST_FLAG)
                hdrs_len += TPA_TSTAMP_OPT_LEN;

        skb_shinfo(skb)->gso_size = len_on_bd - hdrs_len;
...