From owner-cvs-src@FreeBSD.ORG Wed Apr 26 06:04:22 2006 Return-Path: X-Original-To: cvs-src@FreeBSD.org Delivered-To: cvs-src@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4CB0D16A45C; Wed, 26 Apr 2006 06:04:22 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id A128243D45; Wed, 26 Apr 2006 06:04:21 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.254.11] (junior.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.4/8.13.4) with ESMTP id k3Q648or088004; Wed, 26 Apr 2006 00:04:08 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <444F0D58.9020000@samsco.org> Date: Wed, 26 Apr 2006 00:04:08 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.12) Gecko/20051230 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Matthew Jacob References: <444E7750.206@samsco.org> <200604251540.00170.jhb@freebsd.org> <444E7BFE.4040800@samsco.org> <20060425.173236.74726638.imp@bsdimp.com> <444EB6A1.3060901@samsco.org> <20060426103623.M1847@epsplex.bde.org> <20060425223519.F65802@ns1.feral.com> <444F0923.8050508@samsco.org> <20060425224750.K65869@ns1.feral.com> In-Reply-To: <20060425224750.K65869@ns1.feral.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.4 required=3.8 tests=ALL_TRUSTED autolearn=failed version=3.1.1 X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on pooker.samsco.org Cc: src-committers@FreeBSD.org, jhb@FreeBSD.org, Bruce Evans , cvs-src@FreeBSD.org, cvs-all@FreeBSD.org, Warner Losh Subject: Re: cvs commit: src/sys/dev/bce if_bcereg.h X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Apr 2006 06:04:22 -0000 Matthew Jacob wrote: >>> >>> I'm afraid I don't understand the 'unreasonable' argument here. Linux >>> is eating your lunch today. Do you want it to eat your dessert as well? >>> >>> -matt >>> >> >> bus_size_t is used for things like measuring transfer segment size. >> There is little chance that Linux, Windows, FreeBSD, or any other OS >> is ever going to try to DMA more than 2^32 bytes of data in a single >> bus transaction. Maybe you could contrive a silly infiniband device >> to do it. Anyways, it has no bearing on whether the CPU, memory >> controller, or PCI buses can do 64 bit addressing. > > > Oh, sorry, yes, I agree it's *unlikely* that anything will DMA more than > 2^32 bytes at a time right now. I'm really really tired and lost lock. > Sorry. > And actually, it's 100% impossible to do a transfer larger than 2^32 on PCI Express due to the protocol requiring that a transfer not cross a 4GB boundary. So, I think that we are pretty safe with this typedef for the next 5-10 years. Of course, I'll be honored when Linus calls me a moron for this 7 years from now =-) Scott