From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753608AbYKNESc (ORCPT ); Thu, 13 Nov 2008 23:18:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751206AbYKNESW (ORCPT ); Thu, 13 Nov 2008 23:18:22 -0500 Received: from kroah.org ([198.145.64.141]:55318 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750984AbYKNESV (ORCPT ); Thu, 13 Nov 2008 23:18:21 -0500 Date: Thu, 13 Nov 2008 20:15:13 -0800 From: Greg KH To: Randy Dunlap Cc: Michael Ellerman , linux-kernel@vger.kernel.org, Andrew Morton , viro@zeniv.linux.org.uk Subject: Re: [PATCH] Store the relevant miscdevice in file->private_data in misc_open() Message-ID: <20081114041513.GA17946@kroah.com> References: <20081113173127.GB30811@kroah.com> <1226620481.8066.18.camel@localhost> <20081114001818.GB20023@kroah.com> <1226631052.8066.25.camel@localhost> <20081114032313.GB15204@kroah.com> <491CF82B.7040703@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <491CF82B.7040703@oracle.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 13, 2008 at 08:01:47PM -0800, Randy Dunlap wrote: > Greg KH wrote: > > On Fri, Nov 14, 2008 at 01:50:52PM +1100, Michael Ellerman wrote: > >> On Thu, 2008-11-13 at 16:18 -0800, Greg KH wrote: > >>> On Fri, Nov 14, 2008 at 10:54:41AM +1100, Michael Ellerman wrote: > >>>> On Thu, 2008-11-13 at 09:31 -0800, Greg KH wrote: > >>>>> On Thu, Nov 13, 2008 at 03:49:50PM +1100, Michael Ellerman wrote: > >>>>>> Currently it's not easy to share file_operations between multiple > >>>>>> instances of a miscdevice. In order to do this, the device code needs to > >>>>>> store a list of all it's miscdevice instances, and when fops->open() is > >>>>>> called, search the list and find the right device based on the minor > >>>>>> number. > >>>>>> > >>>>>> However the generic miscdevice code already has a list of miscdevices, > >>>>>> and uses this to find the right device in misc_open(). If misc_open() > >>>>>> would store the miscdevice it found in file->private_data, then the > >>>>>> device code wouldn't need to worry about storing it's own separate list > >>>>>> and searching that as well. > >>>>>> > >>>>>> The rest of the miscdevice code does not use file->private_data, so the > >>>>>> device code is still free to use file->private_data for something else > >>>>>> if it wants to. > >>>>>> > >>>>>> Signed-off-by: Michael Ellerman > >>>>> Do you have a follow-on patch for some misc device using code that would > >>>>> take advantage of this change? > >>>> Ah, good point. I do, but not for upstream :/ > >>> Hm, then I have to ask why should we take this change? > >> Because it's seems like a good idea. > > > > You know we don't make changes to core code for drivers that aren't in > > the main tree, this is not a new thing... > > > >>> And why would the driver not be availble for upstream to take? > >> Because it's a hacky pile of crud, and it's for unreleased and > >> non-existent hardware. > > > > That's what the drivers/staging/ tree is for, send it on over to me and > > I'll add it to that location. > > for non-existent hardware?? that's not a good plan. I read that as "not public yet" hardware. If that is incorrect, Randy is right, this isn't a good idea at all, sorry. thanks, greg k-h