From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Domsch Subject: Re: [SUBJECT CHANGE]: megaraid unified driver version 2.20.0.0-al pha1 Date: Wed, 25 Feb 2004 20:44:10 -0600 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20040225204410.A28880@lists.us.dell.com> References: <0E3FA95632D6D047BA649F95DAB60E57033BC3EA@exa-atlanta.se.lsil.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from lists.us.dell.com ([143.166.224.162]:56294 "EHLO lists.us.dell.com") by vger.kernel.org with ESMTP id S261528AbUBZCox (ORCPT ); Wed, 25 Feb 2004 21:44:53 -0500 Content-Disposition: inline In-Reply-To: <0E3FA95632D6D047BA649F95DAB60E57033BC3EA@exa-atlanta.se.lsil.com>; from Atulm@lsil.com on Wed, Feb 25, 2004 at 06:05:43PM -0500 List-Id: linux-scsi@vger.kernel.org To: "Mukker, Atul" Cc: 'Christoph Hellwig' , 'Arjan van de Ven' , 'James Bottomley' , 'Paul Wagland' , Matthew Wilcox , "'linux-kernel@vger.kernel.org'" , "'linux-scsi@vger.kernel.org'" On Wed, Feb 25, 2004 at 06:05:43PM -0500, Mukker, Atul wrote: > Thanks a lot for the valuable feedback. The general consensus is against a > single driver for different class of controllers. This would put a strain on > our applications, which expect all the controllers to be exported from > single driver's private ioctl interface. > > With multiple adapters, applications would need to open multiple handles. > This would somewhat complicate things for them. But keeping in line with > general expectations, we would fork the drivers for different class of > controllers now. It probably isn't difficult to add this to the applications, but since I haven't seen the source code to them, it's hard to say. When I modified efibootmgr to handle either /proc-style or /sys-style entries, whichever was present, it wasn't difficult, and really made the code cleaner. I wouldn't think your tools would be that much more difficult. As Jeff hinted, if your userspace<->driver ABI is consistent between your new MPT-based RAID controllers and your existing megaraid driver, then perhaps you need a single small helper module (lsiioctl or some better name), loaded by both mptraid and megaraid automatically, which handles registering the /dev/megaraid node dynamically. In this case, both mptraid and megaraid would register with lsiioctl for each adapter discovered, and lsiioctl would essentially be a switch, redirecting userspace tool ioctls to the appropriate driver. Thanks, Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com