From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45011C433DF for ; Sun, 26 Jul 2020 03:24:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FEB42064C for ; Sun, 26 Jul 2020 03:24:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="k2ub80at" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728234AbgGZDYP (ORCPT ); Sat, 25 Jul 2020 23:24:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727861AbgGZDYP (ORCPT ); Sat, 25 Jul 2020 23:24:15 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CFF8C0619D2; Sat, 25 Jul 2020 20:24:15 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id m22so7499316pgv.9; Sat, 25 Jul 2020 20:24:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ylSob1TfxL3wF+3P8pCCtn06XFXpIg3kaDnuq9sg5J0=; b=k2ub80atQf46SM7/tv2X1i5R3DEErzZ+5J1pDTbRGubw1XCD+DnyiF9iIQqEHYVUCv o6BXq3bJUYrDP8iWyGNNQfvmmbMwld0HjMotsunHMVizTYd4sX9q/NTu+VVP2yTcBuPX 2nI1eFpeTO7OdNrmJxv2W12JACp81Ndt750FcTHN9O4WvxjfpLgqCaePgrav+atoy6Wy JsQXlKDPCQNkEG/r/rFWPezY+ly+1v/7RCq82xsKSuhkhMa2zBkgEhZo9oGLnhBkWPTR kiV/TK0NMmJu8zSUnd8CpW4LV0doxlicwCC7SSbtlhgAxlU5O9CtoluaCz4g8X4RQjGW s0hg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ylSob1TfxL3wF+3P8pCCtn06XFXpIg3kaDnuq9sg5J0=; b=LSmuvgAN5tfQ6MlMmPhvEQ7gTVxGNvkRXqwXyVKdYvNbi4eV0HWF3+XVeaFdHa3sAf CyzUy64iVkaPr4a2rztfTSQSeKXTZCSmrT3NoliMaYAI3k3sze7xzGE2U7yZLPLKboba KtMOqBYeEzCavyXEWirQ2HKX6eQgeUAM71/Lz7FpTbUt57JZXZ7fbQRUGTEvRltkjyPM FYztJtBFlG7esrLJoXaP4VRdOCCWXcI9+RYnI1nHak10VD5pV4zWvpIuEp7MLv8pN2hU FydAdwtI21xXJIu4EKgFAihQrySCDQKMCtNe7iPlsfmBOvSgjFN8sSIIaXwWnYeZfX0V Nn0w== X-Gm-Message-State: AOAM533FFNvp4viEQGvvhrKa2OklnxacQVk6tH640Gz336Q48oIFJyoB 9q25vE/ABro/r8G4RZ8LPJQ= X-Google-Smtp-Source: ABdhPJysDocBa2t+oK0J0mwTR7+EBG8WGAOvXaR/dVfcTe8Oh0Yqf99qil8drFBSKSCjWZb8TMkKnQ== X-Received: by 2002:aa7:871a:: with SMTP id b26mr14868460pfo.294.1595733854896; Sat, 25 Jul 2020 20:24:14 -0700 (PDT) Received: from sol (106-69-185-93.dyn.iinet.net.au. [106.69.185.93]) by smtp.gmail.com with ESMTPSA id x10sm9771159pgp.47.2020.07.25.20.24.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 25 Jul 2020 20:24:14 -0700 (PDT) Date: Sun, 26 Jul 2020 11:24:08 +0800 From: Kent Gibson To: Andy Shevchenko Cc: Linux Kernel Mailing List , "open list:GPIO SUBSYSTEM" , Bartosz Golaszewski , Linus Walleij Subject: Re: [PATCH v2 05/18] gpiolib: cdev: support GPIO_GET_LINE_IOCTL and GPIOLINE_GET_VALUES_IOCTL Message-ID: <20200726032408.GA78235@sol> References: <20200725041955.9985-1-warthog618@gmail.com> <20200725041955.9985-6-warthog618@gmail.com> <20200726011244.GA6587@sol> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200726011244.GA6587@sol> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Sun, Jul 26, 2020 at 09:12:44AM +0800, Kent Gibson wrote: > On Sat, Jul 25, 2020 at 11:51:54PM +0300, Andy Shevchenko wrote: > > On Sat, Jul 25, 2020 at 7:24 AM Kent Gibson wrote: > > > [ snip ] > > > > > +static bool padding_not_zeroed(__u32 *padding, int pad_size) > > > +{ > > > + int i, sum = 0; > > > + > > > + for (i = 0; i < pad_size; i++) > > > + sum |= padding[i]; > > > + > > > + return sum; > > > +} > > > > Reimplementation of memchr_inv() ? > > > > I was hoping to find an existing function, surely checking a region is > zeroed is a common thing, right?, so this was a place holder as much > as anything. Not sure memchr_inv fits the bill, but I'll give it a > try... > I gave it a try. It is a good fit functionally, but in my build it results in a larger object by ~104 bytes. I assume that is because padding_not_zeroed is being inlined, and otherwise optimized, while memchr_inv calls aren't. As such I'm inclined to leave it as is - unless there are other objections. Cheers, Kent.