Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755485AbYAFTzH (ORCPT ); Sun, 6 Jan 2008 14:55:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753192AbYAFTy4 (ORCPT ); Sun, 6 Jan 2008 14:54:56 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:33335 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752858AbYAFTyz (ORCPT ); Sun, 6 Jan 2008 14:54:55 -0500 From: "Rafael J. Wysocki" To: Alan Stern Subject: Re: [PATCH] PM: Acquire device locks on suspend Date: Sun, 6 Jan 2008 20:57:00 +0100 User-Agent: KMail/1.9.6 (enterprise 20070904.708012) Cc: Greg KH , Andrew Morton , Len Brown , Ingo Molnar , ACPI Devel Maling List , LKML , pm list References: <200801062005.12097.rjw@sisk.pl> In-Reply-To: <200801062005.12097.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200801062057.01677.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1629 Lines: 50 On Sunday, 6 of January 2008, Rafael J. Wysocki wrote: > On Sunday, 6 of January 2008, Alan Stern wrote: > > On Sun, 6 Jan 2008, Rafael J. Wysocki wrote: > > > > > > If you can figure out a way to disable the warning in device_del() for > > > > just the one device being unregistered by > > > > device_pm_destroy_suspended(), > > > > > > Something like this, perhaps: > > > > > > @@ -905,6 +915,18 @@ void device_del(struct device * dev) > > > struct device * parent = dev->parent; > > > struct class_interface *class_intf; > > > > > > + if (down_trylock(&dev->sem)) { > > > + if (pm_sleep_lock()) { > > > + dev_warn(dev, "Illegal %s during suspend\n", > > > + __FUNCTION__); > > > + dump_stack(); > > > + } else { > > > + pm_sleep_unlock(); > > > + } > > > + } else { > > > + up(&dev->sem); > > > + } > > > + > > > if (parent) > > > klist_del(&dev->knode_parent); > > > if (MAJOR(dev->devt)) > > > > Bizarre, but it should work. > > OK > > Still, shouldn't we fail the removal of the device apart from giving the > warning? Actually, having thought about it a bit more, I don't see the point in preventing the removal of the device from the list in device_pm_remove() if we allow all of the operations in device_del() preceding it to be performed. Shouldn't we just take pm_sleep_rwsem in device_del() upfront and block on that if locked? Rafael -- 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/