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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 966EAC28CF6 for ; Thu, 26 Jul 2018 08:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 549A42064D for ; Thu, 26 Jul 2018 08:35:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 549A42064D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729103AbeGZJv2 (ORCPT ); Thu, 26 Jul 2018 05:51:28 -0400 Received: from mga09.intel.com ([134.134.136.24]:65330 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727951AbeGZJv1 (ORCPT ); Thu, 26 Jul 2018 05:51:27 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Jul 2018 01:35:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,404,1526367600"; d="scan'208";a="74654639" Received: from devel-ww.sh.intel.com ([10.239.48.110]) by fmsmga004.fm.intel.com with ESMTP; 26 Jul 2018 01:35:39 -0700 From: Wei Wang To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, ynorov@caviumnetworks.com, corbet@lwn.net, linux@rasmusvillemoes.dk Cc: dgilbert@redhat.com, mawilcox@microsoft.com, wei.w.wang@intel.com Subject: [PATCH] linux/bitmap.h: fix BITMAP_LAST_WORD_MASK Date: Thu, 26 Jul 2018 16:07:51 +0800 Message-Id: <1532592471-21177-1-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The existing BITMAP_LAST_WORD_MASK macro returns 0xffffffff if nbits is 0. This patch changes the macro to return 0 when there is no bit needs to be masked. Signed-off-by: Wei Wang Cc: Andrew Morton Cc: Rasmus Villemoes Cc: Yury Norov --- include/linux/bitmap.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 1ee46f4..12af3d7 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -194,7 +194,10 @@ extern int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, int nmaskbits); #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) -#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) +#define BITMAP_LAST_WORD_MASK(nbits) \ +( \ + nbits ? (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) : 0 \ +) #define small_const_nbits(nbits) \ (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG) -- 2.7.4