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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 02C2BC43381 for ; Tue, 26 Mar 2019 03:13:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF73E20828 for ; Tue, 26 Mar 2019 03:13:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TrjA+eap" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730660AbfCZDNY (ORCPT ); Mon, 25 Mar 2019 23:13:24 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:41306 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727157AbfCZDNX (ORCPT ); Mon, 25 Mar 2019 23:13:23 -0400 Received: by mail-pl1-f193.google.com with SMTP id y5so925866plk.8; Mon, 25 Mar 2019 20:13:23 -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:user-agent; bh=MinFei9y55S8BB3lIJN4Zd2NC15gAsU5rmUgcJ/yuXI=; b=TrjA+eapEbjBMS8P7sEKmLpBp0YEw+GcQcONqsGvTaqETKh+x+NLKocqs9zPHNR13F m+BYYqLlu1cf4zDi4dz3L8CxrMGJ+OvKBdP/pcRa7aZgbh/JBWKr7J772+2Z8LWhXQd2 VsNJIDMK1iVKhT8Bd5HQ0xiI+h80584mliCEwN+dUlG1IW6xVaFK5+a25wmj+QfMT04F koJVn4ovW5BxgaNP9v3aZlES5gpEBnkpQoJRVhqsRhBbLszkve9is/TYdolnPABlMhAy oZYB/PEIcI9syoGbEhKQ3LVdAZ4LkC+B8G7KU8LUxRHUK4gStnKBjDeY1bm4PSMBzV7v PWXQ== 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:user-agent; bh=MinFei9y55S8BB3lIJN4Zd2NC15gAsU5rmUgcJ/yuXI=; b=SfNAcuna+gHRyKWAxq602iDr0QY4SLTfzcUdhj+rZnp/OJg4+9zdErZCqfXcNOrNIk KbyrmBSaz3BrhV4jwlEqIfJQhSMaKLfqr6Ul2jlJSt+z8C82mOr+WoSvCY6l4Cva6MbN Wq/HCuO86lbKmRG67XQ7bod/GJ825s3nK8CmIUmyLt7dgEAcDVZ/UZ5PmgP/HT4R+ya9 Qap8NXrM8cE2UheIMXyqzxqMC75Gg2V2NBEA7K5cJ1wBoAsv28+blKCngZeoT7oJtAwL j7O7EodjNsuSrqVYfeXtIPLvuQzw7Lm6xoj5Xnk4aOmOlxMwK+QZQN1YiDy1ANTqdg7R u96A== X-Gm-Message-State: APjAAAXmqbYmLQXwMzQuDeCpGIaMQWKJQK1/7oJECDe3Q8rY+WOSjVmp zGpwTFUnzZVMOKpq8l39C0M= X-Google-Smtp-Source: APXvYqwSFiRdDaTC0unzOdl6OozUx1Di7vdpvlhIFLAoPI/PoJwnq/bdkwslNzOq2Jz4dD1X0QaKqA== X-Received: by 2002:a17:902:9a98:: with SMTP id w24mr28467310plp.247.1553570002759; Mon, 25 Mar 2019 20:13:22 -0700 (PDT) Received: from icarus ([2001:268:c0a3:6e7a:c70:4af9:86e2:2]) by smtp.gmail.com with ESMTPSA id b133sm23029909pfb.62.2019.03.25.20.13.17 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Mar 2019 20:13:22 -0700 (PDT) Date: Tue, 26 Mar 2019 12:14:22 +0900 From: William Breathitt Gray To: Lukas Wunner Cc: linus.walleij@linaro.org, bgolaszewski@baylibre.com, akpm@linux-foundation.org, linux-gpio@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yamada.masahiro@socionext.com, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, geert@linux-m68k.org, preid@electromag.com.au, Andy Shevchenko , Arnd Bergmann Subject: Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro Message-ID: <20190326031422.GB3356@icarus> References: <9afc30a574ce3e6a86b51dd522146a1d2156dedd.1553494625.git.vilhelm.gray@gmail.com> <20190325093854.jzkkwaksxi7zvtrg@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190325093854.jzkkwaksxi7zvtrg@wunner.de> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 25, 2019 at 10:38:54AM +0100, Lukas Wunner wrote: > On Mon, Mar 25, 2019 at 03:22:23PM +0900, William Breathitt Gray wrote: > > +/** > > + * find_next_clump8 - find next 8-bit clump with set bits in a memory region > > + * @clump: location to store copy of found clump > > + * @addr: address to base the search on > > + * @offset: bit offset at which to start searching > > + * @size: bitmap size in number of bits > > + * > > + * Returns the bit offset for the next set clump; the found clump value is > > + * copied to the location pointed by @clump. If no bits are set, returns @size. > > + */ > > +unsigned int find_next_clump8(unsigned long *const clump, > > + const unsigned long *const addr, > > + unsigned int offset, const unsigned int size) > > +{ > > + for (; offset < size; offset += 8) { > > + *clump = bitmap_get_value8(addr, size, offset); > > + if (!*clump) > > + continue; > > + > > + return offset; > > + } > > + > > + return size; > > +} > > +EXPORT_SYMBOL(find_next_clump8); > > Just use find_first_bit() / find_next_bit() to use optimized arch-specific > bitops instead of open-coding the iteration over the bitmap. > > See max3191x_get_multiple() for an example. > > Thanks, > > Lukas Is this the sort of implementation you had in mind: offset = find_next_bit(addr, size, offset); if (offset == size) return size; offset -= offset % 8; *clump = bitmap_get_value8(addr, size, offset); return offset; Yes, this does seem more efficient to leverage the existing find_next_bit function. Should the offset and size parameters be redefined as unsigned long to match the find_first_bit/find_next_bit function parameters? William Breathitt Gray