From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: [PATCH 1/4] sas: add flag for locally attached PHYs Date: Fri, 21 Oct 2005 10:16:30 +0200 Message-ID: <1129882591.2786.9.camel@laptopd505.fenrus.org> References: <91888D455306F94EBD4D168954A9457C048F0E34@nacos172.co.lsil.com> <20051020160155.GA14296@lst.de> <4357CB03.4020400@adaptec.com> <20051020170330.GA16458@lst.de> <1129828959.2807.18.camel@laptopd505.fenrus.org> <4357F9D0.3090602@adaptec.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:60067 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932114AbVJUIQg (ORCPT ); Fri, 21 Oct 2005 04:16:36 -0400 In-Reply-To: <4357F9D0.3090602@adaptec.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Luben Tuikov Cc: Christoph Hellwig , linux-scsi@vger.kernel.org, jejb@steeleye.com, "Moore, Eric Dean" On Thu, 2005-10-20 at 16:10 -0400, Luben Tuikov wrote: > You see? You don't need IOCTLs, yet you can be fully compliant > to the spec so that already existing user space management programs > can transition with minimal change to their code (over to the front > end: sg/whatever). this is EXACTLY my point. A proper API would NOT need the userland apps to change if the underlying mechanism changes. Or in other words: today it may be SG, tomorrow BSG or SysFS, and when we open 2.7 the mechanism may be WokkieWokkie. The implementation of the interface library may need to change for this, but the management app should not. There is a parallel in the glibc/posix/sus world: With the 2.6 kernel there is a new syscall mechanism (sysenter) on x86 kernels available. NONE of the applications needed changing, fopen() remained fopen(), not just as API but also as ABI. All that needed some adjustments were glibc internals.