From nobody Thu Nov 6 18:19:02 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1542278623303690.778865963717; Thu, 15 Nov 2018 02:43:43 -0800 (PST) Received: from localhost ([::1]:37975 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gNF7e-0005Wz-5F for importer@patchew.org; Thu, 15 Nov 2018 05:43:42 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57580) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gNF5B-0003hW-KW for qemu-devel@nongnu.org; Thu, 15 Nov 2018 05:41:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gNF57-0000pA-BR for qemu-devel@nongnu.org; Thu, 15 Nov 2018 05:41:09 -0500 Received: from mga03.intel.com ([134.134.136.65]:14567) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gNF57-0000oM-2h for qemu-devel@nongnu.org; Thu, 15 Nov 2018 05:41:05 -0500 Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Nov 2018 02:41:05 -0800 Received: from devel-ww.sh.intel.com ([10.239.48.119]) by fmsmga004.fm.intel.com with ESMTP; 15 Nov 2018 02:41:02 -0800 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,236,1539673200"; d="scan'208";a="106467266" From: Wei Wang To: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com Date: Thu, 15 Nov 2018 18:07:57 +0800 Message-Id: <1542276484-25508-2-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1542276484-25508-1-git-send-email-wei.w.wang@intel.com> References: <1542276484-25508-1-git-send-email-wei.w.wang@intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.65 Subject: [Qemu-devel] [PATCH v9 1/8] bitmap: fix bitmap_count_one X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: liliang.opensource@gmail.com, peterx@redhat.com, wei.w.wang@intel.com, pbonzini@redhat.com, nilal@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" BITMAP_LAST_WORD_MASK(nbits) returns 0xffffffff when "nbits=3D0", which makes bitmap_count_one fail to handle the "nbits=3D0" case. It appears to be preferred to remain BITMAP_LAST_WORD_MASK identical to the kernel implementation that it is ported from. So this patch fixes bitmap_count_one to handle the nbits=3D0 case. Inital Discussion Link: https://www.mail-archive.com/qemu-devel@nongnu.org/msg554316.html Signed-off-by: Wei Wang CC: Juan Quintela CC: Dr. David Alan Gilbert CC: Peter Xu --- include/qemu/bitmap.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 509eedd..679f1bd 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -221,6 +221,10 @@ static inline int bitmap_intersects(const unsigned lon= g *src1, =20 static inline long bitmap_count_one(const unsigned long *bitmap, long nbit= s) { + if (unlikely(!nbits)) { + return 0; + } + if (small_nbits(nbits)) { return ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits)); } else { --=20 1.8.3.1