From patchwork Sun Mar 21 21:54:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 12153353 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=-15.8 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,USER_AGENT_GIT autolearn=unavailable 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 B4CB9C433ED for ; Sun, 21 Mar 2021 21:56:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9522D61943 for ; Sun, 21 Mar 2021 21:56:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231479AbhCUVzj (ORCPT ); Sun, 21 Mar 2021 17:55:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231431AbhCUVzG (ORCPT ); Sun, 21 Mar 2021 17:55:06 -0400 Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBE36C061764; Sun, 21 Mar 2021 14:55:05 -0700 (PDT) Received: by mail-qk1-x72e.google.com with SMTP id o5so8726850qkb.0; Sun, 21 Mar 2021 14:55:05 -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=f29jH9p39JWfD2RtS5iC7kXU7OOMGi9+Tjbr7N4HWDA=; b=FgfD9GTvPoa9YBhlZc011prSCq8qTC6AGGpN1pyaTQ34Us90lEiWDk+Y3RwpoNgqQM bVuGGx+62+cA8olEUeC/93lQi916ahpRX13jz/NMDQ6eshKlL5/tvWSSiWv8JiPC9LkH 3TQuSLG8OgMLhF7VaVqnUZA0X4hKDGx3o2Rxb+rkib9zlZ48hM7JVVzxsgoAMR69VuXz 2Kwzv56rulCVal4lDwq9/LeqKtCz6VSduIGWk65nk+sHy4JxtVBsDV9/nzwaBSmSvmcu xOzMHnM75++h4EvCbH+w4by9EpVBGPgf8rjuWywUP6F4LHqOf6jltCxvpcqlr3rVE7Yg 5jIw== 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=f29jH9p39JWfD2RtS5iC7kXU7OOMGi9+Tjbr7N4HWDA=; b=sVcB5j8ZZOUmPlYefE+Kxr4NyOxTFQqFtFkiN4FerdqZhzZR5CdghW3MCRelCIxwc5 P9j22eUDpxbMB/lIZTloeWNoW55KK+BuEMoa1EBPvwpamLc8N4iHS9A4KJyzDVEhZ17y JaE+ciUcksD1fb4J0tXIlQAAmo1QEwJQ+AdxqenOmEHbVJ8yol3rkPGSA3Gx6KUYuGI5 r1E3PsT6cPrgmWDl1uNumx+8iJCiaJ3GUiYy4KS18Q2d7aE7lT9NpINN6+l7y8MjRNDF vdcibLAX5ftrgGmH03Jty03aS48sfKhcfoXkp30UUqJMJowuGoPogGh+vZEd0fiiDXLb ZHJg== X-Gm-Message-State: AOAM53172/Lrs6QQGrVACNc2bcPi2uozvNhckJEQX6BG5U/6lgUYUnUx m76d7WhTw6ARFk6V89l9AiphlMo/1k8= X-Google-Smtp-Source: ABdhPJySPLg/YWK3a/H3R05lY9uZd84miNqrzHUkKCXCOynNx7ZqX/X/MDF+iUXO4/I98hSBuAYANA== X-Received: by 2002:a37:638f:: with SMTP id x137mr8169808qkb.199.1616363704823; Sun, 21 Mar 2021 14:55:04 -0700 (PDT) Received: from localhost ([76.73.146.210]) by smtp.gmail.com with ESMTPSA id 66sm9679104qkk.18.2021.03.21.14.55.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Mar 2021 14:55:04 -0700 (PDT) From: Yury Norov To: linux-kernel@vger.kernel.org Cc: Yury Norov , linux-m68k@lists.linux-m68k.org, linux-arch@vger.kernel.org, linux-sh@vger.kernel.org, Alexey Klimov , Andrew Morton , 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 05/12] lib: extend the scope of small_const_nbits() macro Date: Sun, 21 Mar 2021 14:54:50 -0700 Message-Id: <20210321215457.588554-6-yury.norov@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210321215457.588554-1-yury.norov@gmail.com> References: <20210321215457.588554-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org find_bit would also benefit from small_const_nbits() optimizations. The detailed comment is provided by Rasmus Villemoes. Signed-off-by: Yury Norov Suggested-by: Rasmus Villemoes --- include/asm-generic/bitsperlong.h | 12 ++++++++++++ include/linux/bitmap.h | 8 -------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/include/asm-generic/bitsperlong.h b/include/asm-generic/bitsperlong.h index 3905c1c93dc2..1023e2a4bd37 100644 --- a/include/asm-generic/bitsperlong.h +++ b/include/asm-generic/bitsperlong.h @@ -23,4 +23,16 @@ #define BITS_PER_LONG_LONG 64 #endif +/* + * small_const_nbits(n) is true precisely when it is known at compile-time + * that BITMAP_SIZE(n) is 1, i.e. 1 <= n <= BITS_PER_LONG. This allows + * various bit/bitmap APIs to provide a fast inline implementation. Bitmaps + * of size 0 are very rare, and a compile-time-known-size 0 is most likely + * a sign of error. They will be handled correctly by the bit/bitmap APIs, + * but using the out-of-line functions, so that the inline implementations + * can unconditionally dereference the pointer(s). + */ +#define small_const_nbits(nbits) \ + (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0) + #endif /* __ASM_GENERIC_BITS_PER_LONG */ diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 70a932470b2d..8c4adfa5cceb 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -222,14 +222,6 @@ extern int bitmap_print_to_pagebuf(bool list, char *buf, #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) -/* - * The static inlines below do not handle constant nbits==0 correctly, - * so make such users (should any ever turn up) call the out-of-line - * versions. - */ -#define small_const_nbits(nbits) \ - (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0) - static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) { unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);