From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754782AbbIINPW (ORCPT ); Wed, 9 Sep 2015 09:15:22 -0400 Received: from bhuna.collabora.co.uk ([93.93.135.160]:40067 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754623AbbIINO5 (ORCPT ); Wed, 9 Sep 2015 09:14:57 -0400 Subject: Re: [PATCH 1/3] sysfs: Fix is_visible() support for binary attributes To: Guenter Roeck , Greg KH References: <1441714066-5599-1-git-send-email-emilio.lopez@collabora.co.uk> <1441714066-5599-2-git-send-email-emilio.lopez@collabora.co.uk> <20150908153013.GA6758@roeck-us.net> <20150908191002.GB10156@kroah.com> <20150908193052.GA11106@roeck-us.net> <55EF82A4.5000502@collabora.co.uk> <55EF86F8.3060406@roeck-us.net> <20150909035850.GA5497@kroah.com> <55EFB1B5.1060703@roeck-us.net> Cc: olof@lixom.net, kgene@kernel.org, k.kozlowski@samsung.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org From: =?UTF-8?Q?Emilio_L=c3=b3pez?= Message-ID: <55F030C6.80504@collabora.co.uk> Date: Wed, 9 Sep 2015 10:14:46 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <55EFB1B5.1060703@roeck-us.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/09/15 01:12, Guenter Roeck wrote: > On 09/08/2015 08:58 PM, Greg KH wrote: >> On Tue, Sep 08, 2015 at 06:10:16PM -0700, Guenter Roeck wrote: >>> Hi Emilio, >>> >>> On 09/08/2015 05:51 PM, Emilio López wrote: >>>> Hi Greg & Guenter, >>>> >>> [ ... ] >>>>>>> >>>>>>> Unless I am missing something, this is not explained anywhere, >>>>>>> but it is >>>>>>> not entirely trivial to understand. I think it should be documented. >>>> >>>> I agree. I couldn't find any mention of what this int was supposed >>>> to be by looking at Documentation/ (is_visible is not even mentioned >>>> :/) or include/linux/sysfs.h. Once we settle on something I'll >>>> document it before sending a v2. >>>> >>> In the include file ? No strong preference, though. >>> >>>> By the way, I wrote a quick coccinelle script to match is_visible() >>>> users which reference the index (included below), and it found >>>> references to drivers which do not seem to use any binary >>>> attributes, so I believe changing the index meaning shouldn't be an >>>> issue. >>>> >>> Good. >>> >>>>>> I agree, make i the number of the bin attribute and that should solve >>>>>> this issue. >>>>>> >>>>> No, that would conflict with the "normal" use of is_visible for >>>>> non-binary >>>>> attributes, and make the index all but useless, since the >>>>> is_visible function >>>>> would have to search through all the attributes anyway to figure >>>>> out which one >>>>> is being checked. >>>> >>>> Yeah, using the same indexes would be somewhat pointless, although >>>> not many seem to be using it anyway (only 14 files matched). Others >>>> seem to be comparing the attr* instead. An alternative would be to >>>> use negative indexes for binary attributes and positive indexes for >>>> normal attributes. >>>> >>> ... and I probably wrote or reviewed a significant percentage of >>> those ;-). >>> >>> Using negative numbers for binary attributes is an interesting idea. >>> Kind of unusual, though. Greg, any thoughts on that ? >> >> Ick, no, that's a mess, maybe we just could drop the index alltogether? >> > > No, please don't. Having to manually compare dozens of index pointers > would be > even more of a mess. So, what about keeping it the way it is in the patch, and documenting it thoroughly? Otherwise, we could introduce another "is_bin_visible" function to do this same thing but just on binary attributes, but I'd rather not add a new function pointer if possible. Cheers, Emilio