From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dimitris Michailidis Subject: Re: [PATCH net-next 1/2 RESEND v3] net: use NETIF_F_ALL_TSO for vlan features Date: Thu, 12 May 2011 10:05:54 -0700 Message-ID: <4DCC1372.3040607@chelsio.com> References: <4DCA2B86.9030205@cn.fujitsu.com> <4DCABABB.9040001@chelsio.com> <4DCBAE3B.3070201@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev , eilong@broadcom.com, leedom@chelsio.com To: Shan Wei Return-path: Received: from stargate.chelsio.com ([67.207.112.58]:4769 "EHLO stargate.chelsio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757988Ab1ELRGJ (ORCPT ); Thu, 12 May 2011 13:06:09 -0400 In-Reply-To: <4DCBAE3B.3070201@cn.fujitsu.com> Sender: netdev-owner@vger.kernel.org List-ID: On 05/12/2011 02:54 AM, Shan Wei wrote: > Dimitris Michailidis wrote, at 2011=E5=B9=B405=E6=9C=8812=E6=97=A5 00= :35: >> On 05/10/2011 11:24 PM, Shan Wei wrote: >>> As Dimitris Michailidis suggested, use NETIF_F_ALL_TSO for vlan_fea= tures, >>> which is a mask, but not hw_features. >>> >>> Signed-off-by: Shan Wei >> While these changes aren't wrong I don't see a good reason to make t= hem. I am also curious why you're changing only these three drivers. >=20 > A personal reason to quickly know what device supports ALL TSO, > not to search one by one. :;) But vlan_features doesn't indicate by itself what the device supports, = and it=20 is because of this that you can use NETIF_F_ALL_TSO in vlan_features wi= thout=20 much future breakage risk. There's still the potential that in the fut= ure some=20 additional TSO variant will be added that some of the drivers you're ch= anging=20 support, but not over VLANs, and then they'll need to undo you change. If you want to know which drivers support all TSOs you really need to l= ook at=20 their features and hw_features. One could set NETIF_F_ALL_TSO in vlan_= features=20 of a driver that doesn't support any form of TSO. The way you're check= ing=20 you'd be misled into thinking that driver supports all TSO.