From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752219Ab0IKUWW (ORCPT ); Sat, 11 Sep 2010 16:22:22 -0400 Received: from mail1-out1.atlantis.sk ([80.94.52.55]:40603 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751785Ab0IKUWQ (ORCPT ); Sat, 11 Sep 2010 16:22:16 -0400 From: Ondrej Zary To: David Brownell Subject: Re: [PATCH v2] usbnet: do not count empty skbs as errors in rx_process() Date: Sat, 11 Sep 2010 22:22:03 +0200 User-Agent: KMail/1.9.10 Cc: netdev@vger.kernel.org, Kernel development list References: <704982.67431.qm@web180312.mail.gq1.yahoo.com> In-Reply-To: <704982.67431.qm@web180312.mail.gq1.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201009112222.06149.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 11 September 2010 21:07:59 David Brownell wrote: > --- On Fri, 9/10/10, Ondrej Zary wrote: > > From: Ondrej Zary > > Subject: [PATCH v2] usbnet: do not count empty skbs as errors in > > rx_process() > > NAK to this backwards-incompatible change. > > At this point there's no way to know how many > drivers it breaks ... I do know that counting > such SKBs as errors has previously turned up > link-level errors, and thus led to bugfixes. > > > If rx_fixup() returns an empty skb > > (because it consumed all data inside), > > The canonical reason the SKB would be empty is > because after rx_fixup() removed all header and > trailer data, there was no packet body left. > Which is likely a link error, and has been > worth accounting as such in the past (turned up > bugs on TX or RX sides). > > > do not count it as error. > > > > This is needed for cx82310_eth. > > I'd far rather see that driver fixed, than see > the core usbnet framework broken to avoid such > fixes to a very new driver ... I already tried to explain that the driver is not broken and so it cannot be fixed. It's the way the hardware works and usbnet is not ready for it. I see no way to process a packet that crosses URBs (and thus SKBs) without changing usbnet. -- Ondrej Zary