From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH v2] gianfar: Add I/O barriers when touching buffer descriptor ownership. Date: Wed, 02 May 2007 15:40:20 -0500 Message-ID: <4638F734.2040809@freescale.com> References: <20070502195712.GA16541@ld0162-tx32.am.freescale.net> <4638F0C4.2000406@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: jgarzik@pobox.com, netdev@vger.kernel.org, linuxppc-dev@ozlabs.org To: Kumar Gala Return-path: Received: from de01egw01.freescale.net ([192.88.165.102]:46073 "EHLO de01egw01.freescale.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767009AbXEBUka (ORCPT ); Wed, 2 May 2007 16:40:30 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Kumar Gala wrote: > On May 2, 2007, at 3:12 PM, Scott Wood wrote: >> wmb() is a sync, smp_wmb() is an eieio. Andy told me he would not >> accept a sync in those spots. > > > Sorry, was looking at the iobarrier code. > >> And the driver is already ppc-specific; it uses in/out_be32. > > > True, but its hidden behind the gfar_read/write accessors. > > Your change is a bit more blatant. Well, Segher doesn't want me to use iobarrier (because it's not I/O). Andy doesn't want me to use wmb() (because it's sync). I don't think something like gfar_wmb() would be appropriate. So the remaining options are either eieio(), or a new non-arch-specific, non-driver-specific mem_wmb() (or whatever). While I like the latter option, I don't think this bugfix should have to wait for it. -Scott