From owner-freebsd-net@FreeBSD.ORG Mon May 2 18:09:14 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 8FA7816A4D3 for ; Mon, 2 May 2005 18:09:14 +0000 (GMT) Received: from mail25.sea5.speakeasy.net (mail25.sea5.speakeasy.net [69.17.117.27]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3EF8843D79 for ; Mon, 2 May 2005 18:09:14 +0000 (GMT) (envelope-from jmg@hydrogen.funkthat.com) Received: (qmail 11598 invoked from network); 2 May 2005 18:09:12 -0000 Received: from gate.funkthat.com (HELO hydrogen.funkthat.com) ([69.17.45.168]) (envelope-sender ) by mail25.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 2 May 2005 18:09:12 -0000 Received: from hydrogen.funkthat.com (apatmz@localhost.funkthat.com [127.0.0.1])j42I9Cmo003494; Mon, 2 May 2005 11:09:12 -0700 (PDT) (envelope-from jmg@hydrogen.funkthat.com) Received: (from jmg@localhost) by hydrogen.funkthat.com (8.12.10/8.12.10/Submit) id j42I9ACU003493; Mon, 2 May 2005 11:09:10 -0700 (PDT) Date: Mon, 2 May 2005 11:09:10 -0700 From: John-Mark Gurney To: Maksim Yevmenkin Message-ID: <20050502180910.GV2670@funkthat.com> Mail-Followup-To: Maksim Yevmenkin , net@freebsd.org, Sten Spans , Julian Elischer , glebius@FreeBSD.org References: <20050428135120.GB21428@cell.sick.ru> <427111BF.2050607@savvis.net> <42712BAA.4070201@elischer.org> <42715269.3010306@errno.com> <4272743A.2030003@savvis.net> <20050429182819.GP2670@funkthat.com> <42765799.6090201@savvis.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42765799.6090201@savvis.net> User-Agent: Mutt/1.4.1i X-Operating-System: FreeBSD 4.2-RELEASE i386 X-PGP-Fingerprint: B7 EC EF F8 AE ED A7 31 96 7A 22 B3 D8 56 36 F4 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html cc: Sten Spans cc: Julian Elischer cc: net@freebsd.org Subject: Re: if_tap unaligned access problem X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: John-Mark Gurney List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 May 2005 18:09:14 -0000 Maksim Yevmenkin wrote this message on Mon, May 02, 2005 at 09:38 -0700: > >>>>>>i think we have few options here: > >>>>>> > >>>>>>1) revert back original tapwrite function that was changed in v. > >>>>>>1.48 and set offset to 2 bytes in top mbuf > >>>>>> > >>>>>>2) change current version of tapwrite so it would m_prepend and > >>>>>>m_pullup mbuf after m_uiotombuf > >>>>>> > >>>>>>3) change m_uiotombuf to accept one more parameter - mbuf offset at > >>>>>>which data should be copied. there are not that many users of > >>>>>>m_uiotombuf > >> > >>please find and review the attached patch (untested) that implements > >>option (3) above. > > any objections to the attached (revised) patch? can i commit it? > > thanks, > max > Index: sys/kern/uipc_mbuf.c > =================================================================== > RCS file: /home/ncvs/src/sys/kern/uipc_mbuf.c,v > retrieving revision 1.147 > diff -u -r1.147 uipc_mbuf.c > --- sys/kern/uipc_mbuf.c 17 Mar 2005 19:34:57 -0000 1.147 > +++ sys/kern/uipc_mbuf.c 2 May 2005 16:33:41 -0000 > @@ -1333,7 +1333,7 @@ > #endif > > struct mbuf * > -m_uiotombuf(struct uio *uio, int how, int len) > +m_uiotombuf(struct uio *uio, int how, int len, int align) > { > struct mbuf *m_new = NULL, *m_final = NULL; > int progress = 0, error = 0, length, total; > @@ -1342,12 +1342,15 @@ > total = min(uio->uio_resid, len); > else > total = uio->uio_resid; > - if (total > MHLEN) > + if (align >= MHLEN) > + goto nospace; > + if (total + align > MHLEN) I kinda noticed this a bit ago, but didn't think much of it till now... do we want to allow align >= MHLEN if total requires a cluster? since if we use a cluster, we'd have enough space for a larger align... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."