Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756321AbaGION0 (ORCPT ); Wed, 9 Jul 2014 10:13:26 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:50319 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756271AbaGIONY (ORCPT ); Wed, 9 Jul 2014 10:13:24 -0400 Date: Wed, 9 Jul 2014 10:01:06 -0400 From: Konrad Rzeszutek Wilk To: David Vrabel Cc: konrad@kernel.org, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/7] xen/pciback: Don't deadlock when unbinding. Message-ID: <20140709140106.GE21837@laptop.dumpdata.com> References: <1404845909-13563-1-git-send-email-konrad@kernel.org> <1404845909-13563-3-git-send-email-konrad@kernel.org> <53BD33B8.9020901@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53BD33B8.9020901@citrix.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 09, 2014 at 01:21:12PM +0100, David Vrabel wrote: > On 08/07/14 19:58, konrad@kernel.org wrote: > > --- a/drivers/xen/xen-pciback/pci_stub.c > > +++ b/drivers/xen/xen-pciback/pci_stub.c > > @@ -277,10 +277,15 @@ void pcistub_put_pci_dev(struct pci_dev *dev) > > * (so it's ready for the next domain) > > */ > > > > - /* This is OK - we are running from workqueue context > > - * and want to inhibit the user from fiddling with 'reset' > > + /* We might be holding the PCI lock (see comment at the top of the > > + * function) - as such try lock and if we can't then don't worry - > > + * as either: > > + * - we are 'unbind' in which case 'pcistub_device_release' gets > > + * called which does the locked version of this. > > + * - the toolstack has the smarts to do it and has done the > > + * reset on SysFS before assigning this device to another guest. > > */ > > - pci_reset_function(dev); > > + pci_try_reset_function(dev); > > Why not use __pci_reset_function_locked() and ensure all callers of > pcistub_put_pci_dev() are holding the device lock? That could also be done. > > > pci_restore_state(dev); > > If we didn't reset the device there is no need to restore its state. > > David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/