From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752767Ab1ASAlG (ORCPT ); Tue, 18 Jan 2011 19:41:06 -0500 Received: from gir.skynet.ie ([193.1.99.77]:38633 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751446Ab1ASAlE (ORCPT ); Tue, 18 Jan 2011 19:41:04 -0500 Date: Wed, 19 Jan 2011 00:40:40 +0000 From: Mel Gorman To: "Michael S. Tsirkin" Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] vhost: rcu annotation fixup Message-ID: <20110119004040.GE18984@csn.ul.ie> References: <20110118110845.GA11555@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110118110845.GA11555@redhat.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 18, 2011 at 01:08:45PM +0200, Michael S. Tsirkin wrote: > When built with rcu checks enabled, vhost triggers > bogus warnings as vhost features are read without > dev->mutex sometimes. > Fixing it properly is not trivial as vhost.h does not > know which lockdep classes it will be used under. > Disable the warning by stubbing out the check for now. > What is the harm in leaving the bogus warnings until the difficult fix happens? RCU checks enabled does not seem like something that is enabled in production. If this patch is applied, there is always the risk that it'll be simply forgotten about. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab