From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964919AbWFSVwR (ORCPT ); Mon, 19 Jun 2006 17:52:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964922AbWFSVwQ (ORCPT ); Mon, 19 Jun 2006 17:52:16 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:63693 "EHLO einhorn.in-berlin.de") by vger.kernel.org with ESMTP id S964919AbWFSVwQ (ORCPT ); Mon, 19 Jun 2006 17:52:16 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Message-ID: <44971C68.40708@s5r6.in-berlin.de> Date: Mon, 19 Jun 2006 23:51:36 +0200 From: Stefan Richter User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20040914 X-Accept-Language: de, en MIME-Version: 1.0 To: Theodore Tso CC: Al Viro , linux-kernel@vger.kernel.org Subject: Re: [RFC] [PATCH 6/8] inode-diet: Move i_cindex from struct inode to struct file References: <20060619152003.830437000@candygram.thunk.org> <20060619153110.075342000@candygram.thunk.org> <20060619193335.GL27946@ftp.linux.org.uk> <20060619193756.GM27946@ftp.linux.org.uk> <20060619205828.GA20362@thunk.org> In-Reply-To: <20060619205828.GA20362@thunk.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: (0.883) AWL,BAYES_50 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Theodore Tso wrote: > On Mon, Jun 19, 2006 at 08:37:56PM +0100, Al Viro wrote: >>>NAK. Please, take it to the union into cdev part. >> >>Explanation: the whole point of that sucker is to avoid i_rdev use >>in drivers, switching to i_cdev + i_cindex. _Especially_ in open(). >>There is a bunch of other drivers that would get cleaner from that, >>including a lot of tty code. > > The problem is that we already have more stuff in the cdev union > (list_head's are *big*, especially on Opterons), so moving it there > doesn't actually save us anything. > > Moving it into struct file however should be good enough clean up the > character devices drivers that you are concerned about, however. They > are passed the struct file pointer in the file_operations->open call. > So we can clean up the tty code, et. al, by using file->f_cindex just > as easily. > > Furthermore, the inode->i_cindex isn't guaranteed to be valid until > the high-level vfs open code is called anyway, so you might as well > tell people to reference it from filp->f_cindex in the device driver's > open() routine. > > Does that make sense? The patch is obviously proper for usage by any file_operations->open() users like the single current one (or two actually, dv1394_open() and video1394_open()). I don't know if there are any contrary usages planned in other subsystems. -- Stefan Richter -=====-=-==- -==- =--== http://arcgraph.de/sr/