From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261910AbTDFNfP (for ); Sun, 6 Apr 2003 09:35:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262961AbTDFNfP (for ); Sun, 6 Apr 2003 09:35:15 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:64436 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S261910AbTDFNfO (for ); Sun, 6 Apr 2003 09:35:14 -0400 Date: Sun, 6 Apr 2003 14:46:47 +0100 From: "Dr. David Alan Gilbert" To: Michael Buesch Cc: linux-kernel@vger.kernel.org Subject: Re: Serial port over TCP/IP Message-ID: <20030406134647.GK639@gallifrey> References: <200304061447.46393.freesoftwaredeveloper@web.de> <20030406131132.GJ639@gallifrey> <200304061539.00494.freesoftwaredeveloper@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200304061539.00494.freesoftwaredeveloper@web.de> X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/2.5.66 (i686) X-Uptime: 14:40:19 up 1 day, 2:03, 1 user, load average: 0.02, 0.06, 0.09 User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Michael Buesch (freesoftwaredeveloper@web.de) wrote: > On Sunday 06 April 2003 15:11, Dr. David Alan Gilbert wrote: > > I keep thinking that it would be nice to have a mechanism for user space > > char devices; it would have to have a mechanism to pass all the ioctls > > to the process that dealt with it. > > But wouldn't this make too much overhead, if implemented all in userspace? > I say this, because nbd is also implemented in user- und kernel-space. Sure it would have overhead; but it would be a general mechanism and mean that the kernel didn't need lots of char drivers (except for boot time things). Lots of devices are really just filters/wrappers over other more basic devices (look at the growing pile of USB serial device drivers). Most char devices have such a low throughput that the little overhead wouldn't make much difference, but would simplify the kernel. Dave ---------------- Have a happy GNU millennium! ---------------------- / Dr. David Alan Gilbert | Running GNU/Linux on Alpha,68K| Happy \ \ gro.gilbert @ treblig.org | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex / \ _________________________|_____ http://www.treblig.org |_______/