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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 BA024C3A5A9 for ; Sat, 2 May 2020 23:10:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CFBE21775 for ; Sat, 2 May 2020 23:10:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PPc66ANK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726404AbgEBXKr (ORCPT ); Sat, 2 May 2020 19:10:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725844AbgEBXKq (ORCPT ); Sat, 2 May 2020 19:10:46 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21EDFC061A0C; Sat, 2 May 2020 16:10:45 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id h12so5548968pjz.1; Sat, 02 May 2020 16:10:45 -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=k0HGKhgDGnJ07AmBamuhuW5CYFfEnNHsov8zFSgZLxc=; b=PPc66ANK+AeduWoV70+HTU2fa3c7J3XQ45SriigkixGOVWMn7gYPQqFT+YpaW3bOxO ft2lMpHwe9yHQ6NU2ov4roAzgN0bvqLKBPKlBtFu0VxCTl9Ik5GJ79h6z2a1UQz1X8kK qCK51lSyoj478mBsphvTUOft6/yfaGx64qk5c492SO6pOYyHXS4dEyRG/1Tfit1mIwiK a5CyhYOda+8vfbpLE05rClZi2LrdghVUkwyJQK7UVfl5inZZw0nuvE0Vd0GZzutI02SL X/mtT8mpei9A1KsXm3xd4BlttPuK9wnqJpBH8kk0OrsMqaL5ht5orRRFM14xRu8bCByc N17g== 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=k0HGKhgDGnJ07AmBamuhuW5CYFfEnNHsov8zFSgZLxc=; b=BVJvUECQzge3lMK3pUIcxhsH6/tpcqL88ewZL11W3CryWhMj46PJ71ZDwTLQNtACsx 8lWxUFD7xgvK3gSVwZLoZHdmOTwTfqe/PuqqQOxxssYLCUK2GNUrO7pEDxfNRIlGnrVy xD4/iw0JOo/Pv4JL2CM8liwB2islOfBN0SXmnauQlsEscDNrj/IkxE4C4Ks8nxrydBWu w8lWBj1OPxKrS+/s0uXTeOK62C9240FUi2BktTv3SsW/4H5E2Ib4dwG3XOGPLj278gx0 DUCL+xX8J4p9sD5DyD2jJ2cqzQ1vALUVp8O2YUi20LXI0knPCx1f+oCmstumDzir7o4w m4gw== X-Gm-Message-State: AGi0PuZqTwKufxbCYDHEcZjU55qiOlQxY4WAr1QoVqp5FN6DY2hyZuYQ m/ugMLto4svqEtz7d8xQ6hk= X-Google-Smtp-Source: APiQypKZtsvXiNjYCQLhY0aDY7rBWqS1igrLLKsF5uEJ3Ge0Gelsc5SbSkquvHd/1z0HYL/5vOsMuA== X-Received: by 2002:a17:902:dc84:: with SMTP id n4mr11423548pld.281.1588461044667; Sat, 02 May 2020 16:10:44 -0700 (PDT) Received: from syed ([106.210.101.167]) by smtp.gmail.com with ESMTPSA id u12sm5316596pfc.15.2020.05.02.16.10.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 02 May 2020 16:10:44 -0700 (PDT) Date: Sun, 3 May 2020 04:40:24 +0530 From: Syed Nayyar Waris To: akpm@linux-foundation.org Cc: andriy.shevchenko@linux.intel.com, vilhelm.gray@gmail.com, arnd@arndb.de, linus.walleij@linaro.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 1/4] bitops: Introduce the the for_each_set_clump macro Message-ID: <2334ac49d10856db92cb1ca791641fd3200f18af.1588460322.git.syednwaris@gmail.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This macro iterates for each 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_value and bitmap_set_value functions are introduced to respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size less than or equal to BITS_PER_LONG. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving value of n-bits from bitmap. Cc: Arnd Bergmann Signed-off-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray --- Changes in v5: - No change. Changes in v4: - No change Changes in v3: - No change Changes in v2: - No change include/asm-generic/bitops/find.h | 19 ++++++++++ include/linux/bitmap.h | 61 +++++++++++++++++++++++++++++++ include/linux/bitops.h | 13 +++++++ lib/find_bit.c | 14 +++++++ 4 files changed, 107 insertions(+) diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h index 9fdf21302fdf..4e6600759455 100644 --- a/include/asm-generic/bitops/find.h +++ b/include/asm-generic/bitops/find.h @@ -97,4 +97,23 @@ extern unsigned long find_next_clump8(unsigned long *clump, #define find_first_clump8(clump, bits, size) \ find_next_clump8((clump), (bits), (size), 0) +/** + * find_next_clump - find next clump with set bits in a memory region + * @clump: location to store copy of found clump + * @addr: address to base the search on + * @size: bitmap size in number of bits + * @offset: bit offset at which to start searching + * @clump_size: clump size in 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. + */ +extern unsigned long find_next_clump(unsigned long *clump, + const unsigned long *addr, + unsigned long size, unsigned long offset, + unsigned long clump_size); + +#define find_first_clump(clump, bits, size, clump_size) \ + find_next_clump((clump), (bits), (size), 0, (clump_size)) + #endif /*_ASM_GENERIC_BITOPS_FIND_H_ */ diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 99058eb81042..7ab2c65fc964 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -75,7 +75,11 @@ * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst * bitmap_get_value8(map, start) Get 8bit value from map at start + * bitmap_get_value(map, start, nbits) Get bit value of size + * 'nbits' from map at start * bitmap_set_value8(map, value, start) Set 8bit value to map at start + * bitmap_set_value(map, value, start, nbits) Set bit value of size 'nbits' + * of map at start * * Note, bitmap_zero() and bitmap_fill() operate over the region of * unsigned longs, that is, bits behind bitmap till the unsigned long @@ -563,6 +567,34 @@ static inline unsigned long bitmap_get_value8(const unsigned long *map, return (map[index] >> offset) & 0xFF; } +/** + * bitmap_get_value - get a value of n-bits from the memory region + * @map: address to the bitmap memory region + * @start: bit offset of the n-bit value + * @nbits: size of value in bits + * + * Returns value of nbits located at the @start bit offset within the @map + * memory region. + */ +static inline unsigned long bitmap_get_value(const unsigned long *map, + unsigned long start, + unsigned long nbits) +{ + const size_t index = BIT_WORD(start); + const unsigned long offset = start % BITS_PER_LONG; + const unsigned long ceiling = roundup(start + 1, BITS_PER_LONG); + const unsigned long space = ceiling - start; + unsigned long value_low, value_high; + + if (space >= nbits) + return (map[index] >> offset) & GENMASK(nbits - 1, 0); + else { + value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); + value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); + return (value_low >> offset) | (value_high << space); + } +} + /** * bitmap_set_value8 - set an 8-bit value within a memory region * @map: address to the bitmap memory region @@ -579,6 +611,35 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value, map[index] |= value << offset; } +/** + * bitmap_set_value - set n-bit value within a memory region + * @map: address to the bitmap memory region + * @value: value of nbits + * @start: bit offset of the n-bit value + * @nbits: size of value in bits + */ +static inline void bitmap_set_value(unsigned long *map, + unsigned long value, + unsigned long start, unsigned long nbits) +{ + const size_t index = BIT_WORD(start); + const unsigned long offset = start % BITS_PER_LONG; + const unsigned long ceiling = roundup(start + 1, BITS_PER_LONG); + const unsigned long space = ceiling - start; + + value &= GENMASK(nbits - 1, 0); + + if (space >= nbits) { + map[index] &= ~(GENMASK(nbits + offset - 1, offset)); + map[index] |= value << offset; + } else { + map[index] &= ~BITMAP_FIRST_WORD_MASK(start); + map[index] |= value << offset; + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits); + map[index + 1] |= (value >> space); + } +} + #endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 9acf654f0b19..41c2d9ce63e7 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -62,6 +62,19 @@ extern unsigned long __sw_hweight64(__u64 w); (start) < (size); \ (start) = find_next_clump8(&(clump), (bits), (size), (start) + 8)) +/** + * for_each_set_clump - iterate over bitmap for each clump with set bits + * @start: bit offset to start search and to store the current iteration offset + * @clump: location to store copy of current 8-bit clump + * @bits: bitmap address to base the search on + * @size: bitmap size in number of bits + * @clump_size: clump size in bits + */ +#define for_each_set_clump(start, clump, bits, size, clump_size) \ + for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \ + (start) < (size); \ + (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_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 49f875f1baf7..1341bd39b32a 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -190,3 +190,17 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr, return offset; } EXPORT_SYMBOL(find_next_clump8); + +unsigned long find_next_clump(unsigned long *clump, const unsigned long *addr, + unsigned long size, unsigned long offset, + unsigned long clump_size) +{ + offset = find_next_bit(addr, size, offset); + if (offset == size) + return size; + + offset = rounddown(offset, clump_size); + *clump = bitmap_get_value(addr, offset, clump_size); + return offset; +} +EXPORT_SYMBOL(find_next_clump); -- 2.26.2