From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261340AbVBVXUJ (ORCPT ); Tue, 22 Feb 2005 18:20:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261358AbVBVXTy (ORCPT ); Tue, 22 Feb 2005 18:19:54 -0500 Received: from mail.kroah.org ([69.55.234.183]:11401 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S261340AbVBVXQH (ORCPT ); Tue, 22 Feb 2005 18:16:07 -0500 Date: Tue, 22 Feb 2005 15:14:50 -0800 From: Greg KH To: mikem Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: CSMI questions Message-ID: <20050222231450.GB10067@kroah.com> References: <20050222171656.GA5953@beardog.cca.cpqcorp.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050222171656.GA5953@beardog.cca.cpqcorp.net> User-Agent: Mutt/1.5.8i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 22, 2005 at 11:16:56AM -0600, mikem wrote: > All, > I hate to dredge this up again, but, when Eric Moore submitted changes for MPT > Fusion driver containing the CSMI ioctls it was rejected. There was talk on > the linux-scsi list about it being a horrible interface, among other things. > There were also comments about there being a Linux only approach. Personally, > I like that idea but it's not good from a business perspective. Especially > because HP, Dell, and others support more than one OS. Having a unique set of > management apps for each OS would be very cumbersome. Honestly, the kernel developers don't care about cross-OS platform management utilities from a business perspective. :) > We've also been looking at how to use sysfs rather than ioctls. Good. > Some look reasonable, others seem to be restricted by sysfs itself. > 1. only ASCII files are allowed With 1 value in that file. > 2. if multiple attributes are contained in one file, who parses out the data? multiple attributes are not allowed to be contained in a single file. > 3. one buffer of size (PAGE_SIZE) may not hold all of the data required You have a _single_ attribute that is bigger than PAGE_SIZE? What is it? > I'd also like an (brief) explanation of why ioctls are so bad. I've seen the > reasons of them never going away, etc. But from the beginning of time (UNIX) > ioctls have been the preferred method of user space/kernel communication. That's because there was no other method. See the lkml archives for why ioctls are considered bad, I don't want to dredge it up again. Hope this helps, greg k-h