From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <amwang@redhat.com>
Subject: Re: [v2 Patch 1/2] s2io: add dynamic LRO disable support
Date: Tue, 15 Jun 2010 16:26:26 +0800
Message-ID: <4C173932.7010101@redhat.com>
References: <20100609100928.6573.14199.sendpatchset@localhost.localdomain> <1276092058.2093.1.camel@achroite.uk.solarflarecom.com> <FCA91A92EE52B041906A0358FC28FCC38EF13E71B8@FRE1EXCH02.hq.exar.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: Ben Hutchings <bhutchings@solarflare.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"nhorman@redhat.com" <nhorman@redhat.com>,
	"sgruszka@redhat.com" <sgruszka@redhat.com>,
	"herbert.xu@redhat.com" <herbert.xu@redhat.com>,
	"davem@davemloft.net" <davem@davemloft.net>
To: Ramkrishna Vepa <Ramkrishna.Vepa@exar.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:2174 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752857Ab0FOIW2 (ORCPT <rfc822;netdev@vger.kernel.org>);
	Tue, 15 Jun 2010 04:22:28 -0400
In-Reply-To: <FCA91A92EE52B041906A0358FC28FCC38EF13E71B8@FRE1EXCH02.hq.exar.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On 06/10/10 02:52, Ramkrishna Vepa wrote:
>> On Wed, 2010-06-09 at 06:05 -0400, Amerigo Wang wrote:
>> [...]
>>> +static int s2io_ethtool_set_flags(struct net_device *dev, u32 data)
>>> +{
>>> +   struct s2io_nic *sp = netdev_priv(dev);
>>> +   int rc = 0;
>>> +   int changed = 0;
>>> +
>>> +   if (data&  ETH_FLAG_LRO) {
>>> +           if (lro_enable) {
>>> +                   if (!(dev->features&  NETIF_F_LRO)) {
>>> +                           dev->features |= NETIF_F_LRO;
>>> +                           changed = 1;
>>> +                   }
>>> +           } else
>>> +                   rc = -EINVAL;
>>> +   } else if (dev->features&  NETIF_F_LRO) {
>>> +           dev->features&= ~NETIF_F_LRO;
>>> +           changed = 1;
>>> +   }
>>> +
>>> +   if (changed&&  netif_running(dev)) {
>>> +           s2io_stop_all_tx_queue(sp);
>>> +           s2io_card_down(sp);
>>> +           sp->lro = dev->features&  NETIF_F_LRO;
>>> +           rc = s2io_card_up(sp);
>>> +           s2io_start_all_tx_queue(sp);
>> [...]
>>
>> Is it safe to call s2io_start_all_tx_queue() if s2io_card_up() failed?
> Ben,
> Good point. If s2io_card_up() fails the chip will not be accessed, so it's safe but all transmit skbs will be freed without the user knowing the reason for failing to transmit or receive for that matter.  The other option is to return with a failure and get the watchdog timer reset the adapter.
>

(Sorry for the delay, I was on vacation.)

So it seems the latter option is better?

Thanks.