From owner-freebsd-hackers Mon Feb 23 17:04:51 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA05189 for freebsd-hackers-outgoing; Mon, 23 Feb 1998 17:04:51 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (dingo.cdrom.com [204.216.28.145]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA05179 for ; Mon, 23 Feb 1998 17:04:41 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost [127.0.0.1]) by dingo.cdrom.com (8.8.8/8.8.5) with ESMTP id RAA13122; Mon, 23 Feb 1998 17:02:08 -0800 (PST) Message-Id: <199802240102.RAA13122@dingo.cdrom.com> X-Mailer: exmh version 2.0zeta 7/24/97 To: Greg Lehey cc: Mike Smith , "Justin T. Gibbs" , hackers@FreeBSD.ORG Subject: Re: New SoftUpdates test kit In-reply-to: Your message of "Tue, 24 Feb 1998 11:23:04 +1030." <19980224112304.63148@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 23 Feb 1998 17:02:07 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Wouldn't it make more sense to pass around an extended buf structure, > as ccd and vinum do? Put the buf at the start, and you can pass it to > all the routines that normally hand buf structures: No. You can't do this in a device driver - you're handed a buf by someone else, and you give it back when you're done. The problem is that the connection (in the wfd driver) between being given the buf and handing it back involves passing the buf pointer to someone else. To do this with a wrapper as you propose would involve copying the buf into the wrapper and then out again. Bleagh. And you'd still have to manage memory for the wrappers. Bleagh again. The real killer is that there's no universal fragmenting layer sitting on top of device drivers. Another mark for the SLICE stuff. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message