Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759362AbZFZVNh (ORCPT ); Fri, 26 Jun 2009 17:13:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753431AbZFZVN3 (ORCPT ); Fri, 26 Jun 2009 17:13:29 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:33056 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751723AbZFZVN2 (ORCPT ); Fri, 26 Jun 2009 17:13:28 -0400 Date: Fri, 26 Jun 2009 17:13:29 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Rafael J. Wysocki" cc: Greg KH , LKML , ACPI Devel Maling List , Linux-pm mailing list , Ingo Molnar , Arjan van de Ven Subject: Re: [patch update] PM: Introduce core framework for run-time PM of I/O devices (rev. 6) In-Reply-To: <200906262246.39464.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1490 Lines: 38 On Fri, 26 Jun 2009, Rafael J. Wysocki wrote: > > It occurs to me that the problem would be solved if were a cancel_work > > routine. In the same vein, it ought to be possible for > > cancel_delayed_work to run in interrupt context. I'll see what can be > > done. > > Having looked at the workqueue code I'm not sure if there's a way to implement > that in a non-racy way. Which may be the reason why there are no such > functions already. :-) Well, I'll give it a try. Speaking of races, have you noticed that the way power.work_done gets used is racy? You can't wait for the completion before releasing the lock, but then anything could happen. A safer approach would be to use a wait_queue. > In the meantime I reworked the patch (below) to use more RPM_* flags and I > removed the runtime_break and runtime_notify bits from it. Also added some > comments to explain some non-obvious steps (hope that helps). > > I also added the pm_runtime_put_atomic() and pm_runtime_put() as per the > comment above. > > It seems to be a bit cleaner this way, but that's my personal view. :-) I'll look at it over the weekend. And I'll try to see if proper cancel_work and cancel_delayed_work functions can help clean it up. Alan Stern -- 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/