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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, 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 B3C7EC43381 for ; Mon, 25 Mar 2019 13:12:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 819EC20854 for ; Mon, 25 Mar 2019 13:12:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731370AbfCYNMn (ORCPT ); Mon, 25 Mar 2019 09:12:43 -0400 Received: from mga03.intel.com ([134.134.136.65]:59834 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726166AbfCYNMm (ORCPT ); Mon, 25 Mar 2019 09:12:42 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Mar 2019 06:12:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,269,1549958400"; d="scan'208";a="129981054" Received: from smile.fi.intel.com (HELO smile) ([10.237.72.86]) by orsmga006.jf.intel.com with ESMTP; 25 Mar 2019 06:12:38 -0700 Received: from andy by smile with local (Exim 4.92) (envelope-from ) id 1h8PP2-0005vP-9E; Mon, 25 Mar 2019 15:12:36 +0200 Date: Mon, 25 Mar 2019 15:12:36 +0200 From: Andy Shevchenko To: William Breathitt Gray 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, 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, Arnd Bergmann Subject: Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro Message-ID: <20190325131236.GW9224@smile.fi.intel.com> References: <9afc30a574ce3e6a86b51dd522146a1d2156dedd.1553494625.git.vilhelm.gray@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9afc30a574ce3e6a86b51dd522146a1d2156dedd.1553494625.git.vilhelm.gray@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) 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 03:22:23PM +0900, 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. This seems to miss Randy's (IIRC) comment about too many const specifiers. > Suggested-by: Andy Shevchenko > Suggested-by: Rasmus Villemoes > Cc: Arnd Bergmann > Acked-by: Andrew Morton > Reviewed-by: Andy Shevchenko > Reviewed-by: Linus Walleij > Signed-off-by: William Breathitt Gray > --- > include/asm-generic/bitops/find.h | 14 ++++++ > include/linux/bitops.h | 5 ++ > lib/find_bit.c | 81 +++++++++++++++++++++++++++++++ > 3 files changed, 100 insertions(+) > > diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h > index 8a1ee10014de..9a76adff59c6 100644 > --- a/include/asm-generic/bitops/find.h > +++ b/include/asm-generic/bitops/find.h > @@ -80,4 +80,18 @@ extern unsigned long find_first_zero_bit(const unsigned long *addr, > > #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ > > +unsigned long bitmap_get_value8(const unsigned long *const bitmap, > + const unsigned int size, > + const unsigned int start); > + > +void bitmap_set_value8(unsigned long *const bitmap, const unsigned int size, > + const unsigned long value, const unsigned int start); > + > +unsigned int find_next_clump8(unsigned long *const clump, > + const unsigned long *const addr, > + unsigned int offset, const unsigned int size); > + > +#define find_first_clump8(clump, bits, size) \ > + find_next_clump8((clump), (bits), 0, (size)) > + > #endif /*_ASM_GENERIC_BITOPS_FIND_H_ */ > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > index 602af23b98c7..f19a7bc8f559 100644 > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -40,6 +40,11 @@ extern unsigned long __sw_hweight64(__u64 w); > (bit) < (size); \ > (bit) = find_next_zero_bit((addr), (size), (bit) + 1)) > > +#define for_each_set_clump8(start, clump, bits, size) \ > + for ((start) = find_first_clump8(&(clump), (bits), (size)); \ > + (start) < (size); \ > + (start) = find_next_clump8(&(clump), (bits), (start) + 8, (size))) > + > static inline int get_bitmask_order(unsigned int count) > { > int order; > diff --git a/lib/find_bit.c b/lib/find_bit.c > index ee3df93ba69a..1b6f8a6f1957 100644 > --- a/lib/find_bit.c > +++ b/lib/find_bit.c > @@ -218,3 +218,84 @@ EXPORT_SYMBOL(find_next_bit_le); > #endif > > #endif /* __BIG_ENDIAN */ > + > +/** > + * bitmap_get_value8 - get an 8-bit value within a memory region > + * @bitmap: address to the bitmap memory region > + * @size: bitmap size in number of bits > + * @start: bit offset of the 8-bit value > + * > + * Returns the 8-bit value located at the @start bit offset within the @bitmap > + * memory region. > + */ > +unsigned long bitmap_get_value8(const unsigned long *const bitmap, > + const unsigned int size, > + const unsigned int start) > +{ > + const size_t index = BIT_WORD(start); > + const unsigned int offset = start % BITS_PER_LONG; > + const unsigned int low_width = (offset + 8 > BITS_PER_LONG) ? > + BITS_PER_LONG - offset : 8; > + const unsigned long low = bitmap[index] >> offset; > + const unsigned long high = (low_width < 8 && start + 8 <= size) ? > + bitmap[index + 1] << low_width : 0; > + > + return (low | high) & 0xFF; > +} > +EXPORT_SYMBOL(bitmap_get_value8); > + > +/** > + * bitmap_set_value8 - set an 8-bit value within a memory region > + * @bitmap: address to the bitmap memory region > + * @size: bitmap size in number of bits > + * @value: the 8-bit value; values wider than 8 bits may clobber bitmap > + * @start: bit offset of the 8-bit value > + */ > +void bitmap_set_value8(unsigned long *const bitmap, const unsigned int size, > + const unsigned long value, const unsigned int start) > +{ > + const size_t index = BIT_WORD(start); > + const unsigned int offset = start % BITS_PER_LONG; > + const unsigned int low_width = (offset + 8 > BITS_PER_LONG) ? > + BITS_PER_LONG - offset : 8; > + const unsigned long low_mask = GENMASK(low_width - 1, 0) << offset; > + const unsigned int high_width = 8 - low_width; > + const unsigned long high_mask = GENMASK(high_width - 1, 0); > + > + /* set lower portion */ > + bitmap[index] &= ~low_mask; > + bitmap[index] |= value << offset; > + > + /* set higher portion if space available in bitmap */ > + if (high_width && start + 8 <= size) { > + bitmap[index + 1] &= ~high_mask; > + bitmap[index + 1] |= value >> low_width; > + } > +} > +EXPORT_SYMBOL(bitmap_set_value8); > + > +/** > + * 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); > -- > 2.21.0 > -- With Best Regards, Andy Shevchenko