From owner-freebsd-net@FreeBSD.ORG Fri Mar 18 08:48:36 2005 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E504B16A4CF for ; Fri, 18 Mar 2005 08:48:36 +0000 (GMT) Received: from relay02.pair.com (relay02.pair.com [209.68.5.16]) by mx1.FreeBSD.org (Postfix) with SMTP id 5EFC143D2D for ; Fri, 18 Mar 2005 08:48:36 +0000 (GMT) (envelope-from silby@silby.com) Received: (qmail 97646 invoked from network); 18 Mar 2005 08:48:35 -0000 Received: from unknown (HELO localhost) (unknown) by unknown with SMTP; 18 Mar 2005 08:48:35 -0000 X-pair-Authenticated: 209.68.2.70 Date: Fri, 18 Mar 2005 02:48:26 -0600 (CST) From: Mike Silbersack To: John-Mark Gurney In-Reply-To: <20050318082810.GC37984@funkthat.com> Message-ID: <20050318024418.D844@odysseus.silby.com> References: <20050317221359.GN89312@funkthat.com> <20050318021907.H844@odysseus.silby.com> <20050318082810.GC37984@funkthat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed cc: freebsd-net@FreeBSD.org Subject: Re: changes to make ethernet packets able to be unaligned... X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2005 08:48:37 -0000 On Fri, 18 Mar 2005, John-Mark Gurney wrote: >> I'm confused - don't sparc64 and alpha have similar alignment >> requirements? Why does arm require code changes? > > yes, the alignment constraints for arm are the same.. the reason I > said the above is only for arm is the epe driver (which is only on > an ARM core) has been made to use the new feature... > > The changes to ip_input.c will work with other drivers as well... it > just needs to make sure that the proper defines are in amd64 and i386 > so that we don't do the fix up when we don't need to... > > -- > John-Mark Gurney Voice: +1 415 225 5579 Ok, I see what you're saying now, I had forgotten the #ifdef i386 sections we have scattered throughout the network drivers. When I read your original commit, I was thinking about the transmit paths in drivers, which is why m_copyup made no sense to me. Moving the alignment out of the drivers and into a common place seems like a good idea, but I wonder if it should be done in the ethernet code instead of in the ip code; won't other protocols have unaligned access problems if the change is made exactly as is? Mike "Silby" Silbersack