From patchwork Thu Apr 1 00:31:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 12176645 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 263C3C001B6 for ; Thu, 1 Apr 2021 00:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4D5F61029 for ; Thu, 1 Apr 2021 00:33:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233185AbhDAAch (ORCPT ); Wed, 31 Mar 2021 20:32:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233077AbhDAAcI (ORCPT ); Wed, 31 Mar 2021 20:32:08 -0400 Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 073F2C06175F; Wed, 31 Mar 2021 17:32:08 -0700 (PDT) Received: by mail-qv1-xf35.google.com with SMTP id q12so241777qvc.8; Wed, 31 Mar 2021 17:32:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=gxk1x20X1hnopKqSpU5fRPKa2nNYpg8SC0ATwCXnGOY=; b=iDfEDccou2dL1t8r+QrK51cNoAiX2OPuSvlEnLZt0B5H9AhOq6m9oMKC3Uv66Vpcf2 0hrWbZRruD+S3pM5H2DwjUde2HSbaiR+APtwrBWyznYUDiBgGup7Jk9fir96Iuems0uc aPE6Ai5CGAz4OjaFVLrNMV5gmEil/+HIb0VrrTJpQQfZHOGrbrZ4NvOv+mHCrsyd0nlA Dgc1leIrFmLN/tZCC75I1QiqjRAXQotUvMEst1oaZZAnJ3Bgs6RuR21pI2QXgoJyf7jC jdZDYUNBc1XZx+dFnksdby4Asc9/MO1gOB56oF2dppQ0GLuShjYxgVqCO5I38YA6vYs+ le0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gxk1x20X1hnopKqSpU5fRPKa2nNYpg8SC0ATwCXnGOY=; b=YjnEyYblr28V24mCP+gxkdxxUhCwXN+SK89tPvCXuxgnwiry4LjTmBu0eTkLoU6mxE HMl8txQre8HwTizUn29fl7RMLbm/FaaDfAmie+IWo7eSIPcIW1JCNrs9JP0fOtoywnRv VCu1Y/u56m49lCAGabwYAEipebtfGQIrQmQ+gnRUU8mZBFNB25S1wbxdXd3EgHmYOutN Dwbfao5xICaD8LsU5lfF+gLFW0YHvBWJfNXM99zUx6W12vZHiPuVi3vV+vy4JfFRhpSs WlhTp5XsLqLLsonMck5fgxLEL0mjrs77oDcfX2blmxTEkcrINscHLS6LxIv11P5KgiKI E5Sw== X-Gm-Message-State: AOAM533GB/+2gsneHNVKPuDj+FsoAvJU7KtTGJn96BZtxs9LoD+W7OrQ 9jBDHeCy9f9ZUIZ3pLG0BVhfuIDkoPLjGg== X-Google-Smtp-Source: ABdhPJxpDEohmf8RrWI+qZ1o2e1vtGgE92f3rXHNVVQTVhAdgQNCbWXn0xHdk1KZXmuFG5AMIWCDfA== X-Received: by 2002:ad4:5629:: with SMTP id cb9mr5833336qvb.62.1617237126876; Wed, 31 Mar 2021 17:32:06 -0700 (PDT) Received: from localhost ([207.98.216.60]) by smtp.gmail.com with ESMTPSA id 19sm1425205qtt.32.2021.03.31.17.32.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Mar 2021 17:32:06 -0700 (PDT) From: Yury Norov To: linux-kernel@vger.kernel.org, Andrew Morton Cc: Yury Norov , linux-m68k@lists.linux-m68k.org, linux-arch@vger.kernel.org, linux-sh@vger.kernel.org, Alexey Klimov , Andy Shevchenko , Arnd Bergmann , David Sterba , Dennis Zhou , Geert Uytterhoeven , Jianpeng Ma , Joe Perches , John Paul Adrian Glaubitz , Josh Poimboeuf , Rasmus Villemoes , Rich Felker , Stefano Brivio , Wei Yang , Wolfram Sang , Yoshinori Sato Subject: [PATCH 10/12] lib: add fast path for find_first_*_bit() and find_last_bit() Date: Wed, 31 Mar 2021 17:31:51 -0700 Message-Id: <20210401003153.97325-11-yury.norov@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210401003153.97325-1-yury.norov@gmail.com> References: <20210401003153.97325-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org Similarly to bitmap functions, users would benefit if we'll handle a case of small-size bitmaps that fit into a single word. While here, move the find_last_bit() declaration to bitops/find.h where other find_*_bit() functions sit. Signed-off-by: Yury Norov Acked-by: Rasmus Villemoes Acked-by: Andy Shevchenko --- include/asm-generic/bitops/find.h | 50 ++++++++++++++++++++++++++++--- include/linux/bitops.h | 12 -------- lib/find_bit.c | 12 ++++---- 3 files changed, 52 insertions(+), 22 deletions(-) diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h index 4148c74a1e4d..0d132ee2a291 100644 --- a/include/asm-generic/bitops/find.h +++ b/include/asm-generic/bitops/find.h @@ -5,6 +5,9 @@ extern unsigned long _find_next_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long nbits, unsigned long start, unsigned long invert, unsigned long le); +extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size); +extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size); +extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size); #ifndef find_next_bit /** @@ -102,8 +105,17 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, * Returns the bit number of the first set bit. * If no bits are set, returns @size. */ -extern unsigned long find_first_bit(const unsigned long *addr, - unsigned long size); +static inline +unsigned long find_first_bit(const unsigned long *addr, unsigned long size) +{ + if (small_const_nbits(size)) { + unsigned long val = *addr & GENMASK(size - 1, 0); + + return val ? __ffs(val) : size; + } + + return _find_first_bit(addr, size); +} /** * find_first_zero_bit - find the first cleared bit in a memory region @@ -113,8 +125,17 @@ extern unsigned long find_first_bit(const unsigned long *addr, * Returns the bit number of the first cleared bit. * If no bits are zero, returns @size. */ -extern unsigned long find_first_zero_bit(const unsigned long *addr, - unsigned long size); +static inline +unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) +{ + if (small_const_nbits(size)) { + unsigned long val = *addr | ~GENMASK(size - 1, 0); + + return val == ~0UL ? size : ffz(val); + } + + return _find_first_zero_bit(addr, size); +} #else /* CONFIG_GENERIC_FIND_FIRST_BIT */ #ifndef find_first_bit @@ -126,6 +147,27 @@ extern unsigned long find_first_zero_bit(const unsigned long *addr, #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ +#ifndef find_last_bit +/** + * find_last_bit - find the last set bit in a memory region + * @addr: The address to start the search at + * @size: The number of bits to search + * + * Returns the bit number of the last set bit, or size. + */ +static inline +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) +{ + if (small_const_nbits(size)) { + unsigned long val = *addr & GENMASK(size - 1, 0); + + return val ? __fls(val) : size; + } + + return _find_last_bit(addr, size); +} +#endif + /** * find_next_clump8 - find next 8-bit clump with set bits in a memory region * @clump: location to store copy of found clump diff --git a/include/linux/bitops.h b/include/linux/bitops.h index a5a48303b0f1..26bf15e6cd35 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -286,17 +286,5 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, }) #endif -#ifndef find_last_bit -/** - * find_last_bit - find the last set bit in a memory region - * @addr: The address to start the search at - * @size: The number of bits to search - * - * Returns the bit number of the last set bit, or size. - */ -extern unsigned long find_last_bit(const unsigned long *addr, - unsigned long size); -#endif - #endif /* __KERNEL__ */ #endif diff --git a/lib/find_bit.c b/lib/find_bit.c index b03a101367f8..0f8e2e369b1d 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -75,7 +75,7 @@ EXPORT_SYMBOL(_find_next_bit); /* * Find the first set bit in a memory region. */ -unsigned long find_first_bit(const unsigned long *addr, unsigned long size) +unsigned long _find_first_bit(const unsigned long *addr, unsigned long size) { unsigned long idx; @@ -86,14 +86,14 @@ unsigned long find_first_bit(const unsigned long *addr, unsigned long size) return size; } -EXPORT_SYMBOL(find_first_bit); +EXPORT_SYMBOL(_find_first_bit); #endif #ifndef find_first_zero_bit /* * Find the first cleared bit in a memory region. */ -unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) +unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size) { unsigned long idx; @@ -104,11 +104,11 @@ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) return size; } -EXPORT_SYMBOL(find_first_zero_bit); +EXPORT_SYMBOL(_find_first_zero_bit); #endif #ifndef find_last_bit -unsigned long find_last_bit(const unsigned long *addr, unsigned long size) +unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) { if (size) { unsigned long val = BITMAP_LAST_WORD_MASK(size); @@ -124,7 +124,7 @@ unsigned long find_last_bit(const unsigned long *addr, unsigned long size) } return size; } -EXPORT_SYMBOL(find_last_bit); +EXPORT_SYMBOL(_find_last_bit); #endif unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,