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=-0.7 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 E0BA8C10F14 for ; Thu, 10 Oct 2019 05:49:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A28AE218AC for ; Thu, 10 Oct 2019 05:49:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="npag0N6S"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rN9RRE7c" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A28AE218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ktq34rRsSlCW/viv14yJMaybLBLARqDwX27pnfEho7g=; b=npag0N6S0xsDuN jrbidFxG6a15Scwv2c8CARbMkfNEUfM0j7X+gjyYos4We8lUrh3fjGimXu5xGxQCHCgN4XzXJLSdb i+35tD/o8ma74W7XL/ovhMC2uiIYsBc03i1o6yWkEdAYgDcL32r2jQiJw4TvOS4/Y7Xl3luOTPlSc E7Mo2tVmQCe2Syz462lXRDsDOg4P0L/2C4Bjc+x+PA5JN1DIWZ5Mo7qPRM0uQ5tO6jAImycgCzVDG a4jxhZVp84281+T/lN3DqWerpbX1SfUxSA/lVDPdYpRhRGRf59VFC+nRfMa8GIWy3JU2if6zT6V0A RBE0eSYnyfvUMGwgr3yQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iIRKI-0004XO-TP; Thu, 10 Oct 2019 05:49:26 +0000 Received: from mail-pf1-x443.google.com ([2607:f8b0:4864:20::443]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iIRKF-0004Wn-AV for linux-arm-kernel@lists.infradead.org; Thu, 10 Oct 2019 05:49:24 +0000 Received: by mail-pf1-x443.google.com with SMTP id q10so3177660pfl.0 for ; Wed, 09 Oct 2019 22:49:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RhxY1MPKMW6WR/zUFAC74xJM92OHmjB+kj8GPP9wIlw=; b=rN9RRE7cIrRHiqRZYHnHSbHLkLn8sEliKdKOykE1BAiQd6iUPmf/oYzt2zGUIJLtc1 J/Hv96bumBiGBFwkKfJnzTskhdi2HR4zk98z5zCQoBtcrgdsvi4YEfsu8ALTj07La0Z2 y5DSQdzRYQybpa8QuuYByRSJxvy99ZC+pOqw1RuDAryOAY9qmzzrEwX1sEvhtMP8mKu9 Wn0659AVEQs+A8IfAtiI13X+kXbgHTJuPiITwSKFjVxmcEh8gBVFsbX9Dn7NegnpBsx5 cBDj4qkHToVxQk92I5PH9cOFLPLVKWoqKmLZHyR3XAXJDbJ7Fw31c/i5VvJ2MaY8KCxQ A9Yw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RhxY1MPKMW6WR/zUFAC74xJM92OHmjB+kj8GPP9wIlw=; b=a3RJ2CDnheSc3dNF4GbzKw1I9nHr6w7H2ka+K/c7GNBVMPqhSOOg7i/kTkN5jnvSXF E3PXnFaUCpdfal5Nd2HhqbXT/FLm2iswlYetg1W3syOUSHaMN+xgF9HjOrqcp92IfUk4 sV1yUJctvVVKDPh6R9dNEwk+8Owpao48m8ix8FHAYq7x4WkbRB77A4fiIfQZLImrOzDO JfauIuQZ7RIs1nIV3JTv86TrK61sMMEmLkrzqKrO320KHZGrCLKxEJHF72NZxxCB0DTr FVHuTCa2AAeugVPpCjMeg7MOLtdRKmvH1kHKW3TKCE7U/ioYNydAqybwP+HGZfEaO9fH h1Pw== X-Gm-Message-State: APjAAAVXLx9pCnF6GMb9z+jNvzezpf3zMaNkl686CI7bA7AgwA9DjWUM 2NR7BSgn5u6SU1pC5MZwQm4q+HzVMOengQRmDug= X-Google-Smtp-Source: APXvYqxTWGaHrxna/RW71KUqM4PD44f4t6P+cJUv3cQo53Tkjbf14ZESvxDMrwfIJKmfQGqBt7rE4hOcImn0K/p+Em0= X-Received: by 2002:a17:90a:db4a:: with SMTP id u10mr9179621pjx.30.1570686562156; Wed, 09 Oct 2019 22:49:22 -0700 (PDT) MIME-Version: 1.0 References: <893c3b4f03266c9496137cc98ac2b1bd27f92c73.1570633189.git.vilhelm.gray@gmail.com> <20191009170917.GG32742@smile.fi.intel.com> In-Reply-To: From: Andy Shevchenko Date: Thu, 10 Oct 2019 08:49:10 +0300 Message-ID: Subject: Re: [PATCH v17 01/14] bitops: Introduce the for_each_set_clump8 macro To: Masahiro Yamada X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191009_224923_364452_E99EEC7B X-CRM114-Status: GOOD ( 18.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , Phil Reid , Arnd Bergmann , "open list:GPIO SUBSYSTEM" , Linus Walleij , Linux PM mailing list , Rasmus Villemoes , William Breathitt Gray , morten.tiljeset@prevas.dk, Linux Kernel Mailing List , Bartosz Golaszewski , Lukas Wunner , Geert Uytterhoeven , sean.nyekjaer@prevas.dk, Andrew Morton , Andy Shevchenko , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Oct 10, 2019 at 5:31 AM Masahiro Yamada wrote: > On Thu, Oct 10, 2019 at 3:54 AM Geert Uytterhoeven wrote: > > On Wed, Oct 9, 2019 at 7:09 PM Andy Shevchenko > > wrote: > > > On Thu, Oct 10, 2019 at 01:28:08AM +0900, Masahiro Yamada wrote: > > > > On Thu, Oct 10, 2019 at 12:27 AM William Breathitt Gray > > > > wrote: > > > > > > > > > > This macro iterates for each 8-bit group of bits (clump) with set bits, > > > > > within a bitmap memory region. For each iteration, "start" is set to the > > > > > bit offset of the found clump, while the respective clump value is > > > > > stored to the location pointed by "clump". Additionally, the > > > > > bitmap_get_value8 and bitmap_set_value8 functions are introduced to > > > > > respectively get and set an 8-bit value in a bitmap memory region. > > > > > > > Why is the return type "unsigned long" where you know > > > > it return the 8-bit value ? > > > > > > Because bitmap API operates on unsigned long type. This is not only > > > consistency, but for sake of flexibility in case we would like to introduce > > > more calls like clump16 or so. > > > > TBH, that doesn't convince me: those functions explicitly take/return an > > 8-bit value, and have "8" in their name. The 8-bit value is never > > really related to, retrieved from, or stored in a full "unsigned long" > > element of a bitmap, only to/from/in a part (byte) of it. > > > > Following your rationale, all of iowrite{8,16,32,64}*() should take an > > "unsigned long" value, too. > > > > +1 > > Using u8/u16/u32/u64 looks more consistent with other bitmap helpers. > > void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned > int nbits); > void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits); > static inline void bitmap_from_u64(unsigned long *dst, u64 mask); > > > > If you want to see more examples from other parts, Geert's and yours examples both are not related. They are about fixed-width properies when we know that is the part of protocol. Here we have no protocol which stricts us to the mentioned fixed-width types. So, I can tell an opposite, your arguments didn't convince me. Imagine the function which does an or / and / xor operation on bitmap. Now, when I supply unsigned long, I will see operations on one type in _one_ function independently of the size. Your proposal will make an unneded churn. -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel