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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 6C66CC73C64 for ; Tue, 9 Jul 2019 23:29:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3811C2082A for ; Tue, 9 Jul 2019 23:29:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3811C2082A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56796 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkzY4-0000kR-7q for qemu-devel@archiver.kernel.org; Tue, 09 Jul 2019 19:29:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48507) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkzV8-0007CS-Vb for qemu-devel@nongnu.org; Tue, 09 Jul 2019 19:26:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hkzV6-0002sP-RC for qemu-devel@nongnu.org; Tue, 09 Jul 2019 19:26:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52480) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hkzUy-0002eg-Ae; Tue, 09 Jul 2019 19:26:14 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8B900307E040; Tue, 9 Jul 2019 23:26:07 +0000 (UTC) Received: from probe.bos.redhat.com (dhcp-17-215.bos.redhat.com [10.18.17.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 33D035B80B; Tue, 9 Jul 2019 23:26:06 +0000 (UTC) From: John Snow To: qemu-block@nongnu.org, qemu-devel@nongnu.org Date: Tue, 9 Jul 2019 19:25:39 -0400 Message-Id: <20190709232550.10724-8-jsnow@redhat.com> In-Reply-To: <20190709232550.10724-1-jsnow@redhat.com> References: <20190709232550.10724-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 09 Jul 2019 23:26:07 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4 07/18] hbitmap: Fix merge when b is empty, and result is not an alias of a X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , vsementsov@virtuozzo.com, Juan Quintela , John Snow , Xie Changlong , "Dr. David Alan Gilbert" , Max Reitz , Stefan Hajnoczi , Wen Congyang , Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Nobody calls the function like this currently, but we neither prohibit or cope with this behavior. I decided to make the function cope with it. Signed-off-by: John Snow Reviewed-by: Max Reitz --- util/hbitmap.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/util/hbitmap.c b/util/hbitmap.c index 7905212a8b..3b6acae42b 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -781,8 +781,9 @@ bool hbitmap_can_merge(const HBitmap *a, const HBitma= p *b) } =20 /** - * Given HBitmaps A and B, let A :=3D A (BITOR) B. - * Bitmap B will not be modified. + * Given HBitmaps A and B, let R :=3D A (BITOR) B. + * Bitmaps A and B will not be modified, + * except when bitmap R is an alias of A or B. * * @return true if the merge was successful, * false if it was not attempted. @@ -797,7 +798,13 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *= b, HBitmap *result) } assert(hbitmap_can_merge(b, result)); =20 - if (hbitmap_count(b) =3D=3D 0) { + if ((!hbitmap_count(a) && result =3D=3D b) || + (!hbitmap_count(b) && result =3D=3D a)) { + return true; + } + + if (!hbitmap_count(a) && !hbitmap_count(b)) { + hbitmap_reset_all(result); return true; } =20 --=20 2.21.0