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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 C0A31C5B57B for ; Fri, 28 Jun 2019 16:37:24 +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 5C6FF208CB for ; Fri, 28 Jun 2019 16:37:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C6FF208CB 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]:34198 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgtsJ-0000QG-G0 for qemu-devel@archiver.kernel.org; Fri, 28 Jun 2019 12:37:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51573) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgsVr-0006nL-PR for qemu-devel@nongnu.org; Fri, 28 Jun 2019 11:10:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hgsVp-0001Df-Sc for qemu-devel@nongnu.org; Fri, 28 Jun 2019 11:10:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58514) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hgsVn-0001BJ-Mp for qemu-devel@nongnu.org; Fri, 28 Jun 2019 11:10:03 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BCB723E2B9; Fri, 28 Jun 2019 15:09:53 +0000 (UTC) Received: from work-vm (ovpn-116-169.ams2.redhat.com [10.36.116.169]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 73AAB26561; Fri, 28 Jun 2019 15:09:52 +0000 (UTC) Date: Fri, 28 Jun 2019 16:09:50 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Message-ID: <20190628150950.GG2922@work-vm> References: <20190627020822.15485-1-richardw.yang@linux.intel.com> <20190627020822.15485-2-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190627020822.15485-2-richardw.yang@linux.intel.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 28 Jun 2019 15:09:53 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 1/3] migration/postcopy: the valid condition is one less then end 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: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > If one equals end, it means we have gone through the whole bitmap. > > Use a more restrict check to skip a unnecessary condition. > > Signed-off-by: Wei Yang Yes, I don't think that'll break, since I think the find_next_zero_bit will also return end, and then discard_length would be 0; still I think it's a correct fix. Reviewed-by: Dr. David Alan Gilbert > --- > migration/ram.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/migration/ram.c b/migration/ram.c > index 908517fc2b..b78169e811 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -2777,7 +2777,7 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, > for (current = 0; current < end; ) { > unsigned long one = find_next_bit(unsentmap, end, current); > > - if (one <= end) { > + if (one < end) { > unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1); > unsigned long discard_length; > > -- > 2.19.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK