From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raimonds Cicans Subject: Re: r8169: fix driver drop incoming packets >= 1515 if MTU is set between 1515 and 1536 Date: Thu, 12 Nov 2009 00:36:05 +0200 Message-ID: <4AFB3C55.1050906@apollo.lv> References: <4AFB0061.7020908@apollo.lv> <1257964419.2839.58.camel@achroite.uk.solarflarecom.com> <4AFB190F.2020009@apollo.lv> <1257970536.2839.73.camel@achroite.uk.solarflarecom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: romieu@fr.zoreil.com, netdev@vger.kernel.org To: Ben Hutchings Return-path: Received: from smtp2.apollo.lv ([80.232.168.229]:27830 "EHLO smtp2.apollo.lv" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759511AbZKKWgC (ORCPT ); Wed, 11 Nov 2009 17:36:02 -0500 In-Reply-To: <1257970536.2839.73.camel@achroite.uk.solarflarecom.com> Sender: netdev-owner@vger.kernel.org List-ID: Ben Hutchings: > On Wed, 2009-11-11 at 22:05 +0200, Raimonds Cicans wrote: >> Ben Hutchings: >>> On Wed, 2009-11-11 at 20:20 +0200, Raimonds Cicans wrote: >>>> Driver drop incoming packets >=3D 1515(1) if MTU is set between 15= 15(1) and 1536. >>>> >>>> 1) exact number depends on some factors: >>>> - VLAN tagged or not >>>> - patch "r8169: Fix card drop incoming VLAN tagged MTU byte large = jumbo frames" >>>> applied or not >>> [...] >>> >>> MTU is a limit on transmission; it is not required to limit receive= d >>> frames. >> ??? >> >> In r8169 driver MTU is used to calculate receive buffer size. >> Receive buffer size is used to configure hardware incoming packet fi= lter. >> >> For jumbo frames: >> Receive buffer size =3D Max frame size =3D MTU + 14 (ethernet header= ) + 4 >> (vlan header) + 4 (ethernet checksum) =3D MTU + 22 >> >> Bug: >> driver for all MTU up to 1536 use receive buffer size 1536 > [...] >=20 > OK, now I understand. =EF=BB=BFThe subject line you used is not gram= matical and > I originally thought you considered it a bug that the driver might > accept packets with payload greater than MTU. Sorry for my poor English. > To make it clear, perhaps you could change the subject to: > 'r8169: Fix receive buffer length when MTU is between 1515 and 1536' > and then explain the current behaviour below that. Ok. I will try to make new version tomorrow. Raimonds Cicans