Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758370AbZLIWh0 (ORCPT ); Wed, 9 Dec 2009 17:37:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758305AbZLIWhV (ORCPT ); Wed, 9 Dec 2009 17:37:21 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:55515 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758292AbZLIWhT (ORCPT ); Wed, 9 Dec 2009 17:37:19 -0500 From: "Rafael J. Wysocki" To: Ingo Molnar Subject: Re: spinlock in completion_done() (was: Re: Async resume patch (was: Re: [GIT PULL] PM updates for 2.6.33)) Date: Wed, 9 Dec 2009 23:37:52 +0100 User-Agent: KMail/1.12.3 (Linux/2.6.32-rjw; KDE/4.3.3; x86_64; ; ) Cc: Alan Stern , Linus Torvalds , Zhang Rui , LKML , ACPI Devel Maling List , pm list , Peter Zijlstra , David Chinner , Lachlan McIlroy References: <200912082248.14138.rjw@sisk.pl> <20091209092922.GC28428@elte.hu> In-Reply-To: <20091209092922.GC28428@elte.hu> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200912092337.52492.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1564 Lines: 40 On Wednesday 09 December 2009, Ingo Molnar wrote: > > * Rafael J. Wysocki wrote: > > > On Tuesday 08 December 2009, Alan Stern wrote: > > > On Tue, 8 Dec 2009, Rafael J. Wysocki wrote: > > > > > > > BTW, is there a good reason why completion_done() doesn't use spin_lock_irqsave > > > > and spin_unlock_irqrestore? complete() and complete_all() use them, so why not > > > > here? > > > > > > And likewise in try_wait_for_completion(). It looks like a bug. Maybe > > > these routines were not intended to be called with interrupts disabled, > > > but that requirement doesn't seem to be documented. And it isn't a > > > natural requirement anyway. > > > > OK, let's ask Ingo about that. > > > > Ingo, is there any particular reason why completion_done() and > > try_wait_for_completion() don't use spin_lock_irqsave() and > > spin_unlock_irqrestore()? > > that's a bug that should be fixed - all the wakeup side (and atomic) > variants of completetion API should be irq safe. > > It appears that these new completion APIs were added via the XFS tree > about a year ago: > > 39d2f1a: [XFS] extend completions to provide XFS object flush requirements > > Please Cc: scheduler folks to all scheduler patches. If you haven't fixed it locally yet, would you mind me posting a fix? 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/