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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 B10E5ECE58E for ; Thu, 10 Oct 2019 05:49:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A69F2190F for ; Thu, 10 Oct 2019 05:49:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rN9RRE7c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732869AbfJJFtX (ORCPT ); Thu, 10 Oct 2019 01:49:23 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:33959 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726183AbfJJFtX (ORCPT ); Thu, 10 Oct 2019 01:49:23 -0400 Received: by mail-pg1-f193.google.com with SMTP id y35so2952415pgl.1; 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=F7nj+6YmpxvPdixuRntqvQz5inOmXb0mIoPiIzl1s8ayXxHPKynffNnJFCAgTRLjOP eq5X+vs8ZfEnOYrhRg0S6F0u7rXOhohTf1j6kEi/51d4QTD1nNtNWnMh2qoFq+LO+1G8 bW8528f/+sgZIp/iJK3ToYwQVmQFKxhZTkPTxhitnJiNGI2Hm5CY5EOqyW4IrnF/mz/C 32WAr/0uyYq/TkQLZYf4de9ZxhZbLmDfRxKMkEXTzZ9mJS71MPd39cSZ3kGAYmnYYXDp 5IM1LEoLlnoIPUhZzMteeO886OXYCta7UVzPWmRz+/52WUaJdAlMKWjWsK1QjaicsW8v 2Hhg== X-Gm-Message-State: APjAAAVSK7r0LrdGueHgyXHvb0hHXvgpSXmg/exA0UZzjAFCU/UDwmaK p3HKKOxpdN/p7nZfLKpCoQd9/3z10d21jWssoSs= 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 Cc: Geert Uytterhoeven , Andy Shevchenko , William Breathitt Gray , Linus Walleij , Bartosz Golaszewski , Andrew Morton , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , linux-arch , Rasmus Villemoes , linux-arm-kernel , Linux PM mailing list , Phil Reid , Lukas Wunner , sean.nyekjaer@prevas.dk, morten.tiljeset@prevas.dk, Arnd Bergmann Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.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