From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f194.google.com ([209.85.210.194]:45926 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726210AbeJQJrV (ORCPT ); Wed, 17 Oct 2018 05:47:21 -0400 Date: Wed, 17 Oct 2018 10:54:02 +0900 From: William Breathitt Gray Subject: Re: [RESEND PATCH v4 3/8] gpio: 104-dio-48e: Utilize for_each_set_clump macro Message-ID: <20181017015402.GA3307@icarus> References: <5906381114b14d5b0359510a1d23accbd239eaa5.1538441919.git.vilhelm.gray@gmail.com> <822be05b-092b-41c2-3c31-8981acd5cb9e@rasmusvillemoes.dk> <20181014041933.GA7335@icarus> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Rasmus Villemoes Cc: linus.walleij@linaro.org, akpm@linux-foundation.org, linux-gpio@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com Message-ID: <20181017015402.G6D1GhGABfsjHAzcUpHqg8iEvJBF6dcdnOY17cnxizY@z> On Mon, Oct 15, 2018 at 01:59:33PM +0200, Rasmus Villemoes wrote: > On 2018-10-14 06:19, William Breathitt Gray wrote: > > > a bit value of 0 in the > > bits array does not necessarily mean the input was not requested, but > > may instead mean that the value at the input is 0; > > sure enough, but... > > > therefore, the caller > > must keep track of the requested inputs rather than try to deduce them > > from the values in the bits array. > > ...I don't agree that this logically follows. A caller might reasonably > expect not to find any bits set in positions other than those in mask. A > simple example would be caller that just tried to ask "are any of > _these_ inputs set"; it would be reasonable to implement that using > bitmap_empty() on the returned bitset, without first having to mask by > the mask he passed in. > > Rasmus I see your point. It would be good to keep the behavior consistent with what would be expected by the user -- and adding an additional AND operation at the end to mask away the unrequested bits should not really affect the performance to a discernible degree -- so I'll submit a patchset implementing the mask for these drivers some time this weekend. William Breathitt Gray