Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965938Ab2EPUYo (ORCPT ); Wed, 16 May 2012 16:24:44 -0400 Received: from cantor2.suse.de ([195.135.220.15]:40174 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965649Ab2EPUYm (ORCPT ); Wed, 16 May 2012 16:24:42 -0400 Date: Wed, 16 May 2012 22:24:37 +0200 (CEST) From: Jiri Kosina To: Tejun Heo Cc: Linus Torvalds , Stephen Hemminger , Andrew Morton , Jens Axboe , linux-kernel@vger.kernel.org Subject: Re: [PATCH] floppy: convert to delayed work and single-thread wq In-Reply-To: <20120516200147.GD21275@google.com> Message-ID: References: <20120516170124.GA21275@google.com> <20120516195332.GC21275@google.com> <20120516200147.GD21275@google.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1536 Lines: 40 On Wed, 16 May 2012, Tejun Heo wrote: > > > > On Wed, May 16, 2012 at 12:37 PM, Jiri Kosina wrote: > > > > > + ? ? ? cancel_delayed_work_sync(&fd_timeout); > > > > > + ? ? ? cancel_delayed_work_sync(&fd_timer); > > > > > + ? ? ? destroy_workqueue(system_nrt_wq); > > > > > > > > Well, *that* doesn't look right. > > > > > > > > I think just a "flush_workqueue()" is in order. > > > > > > System wqs shouldn't be flushed (nothing guarantees that flush will > > > finish in fixed amount of time). We probably should make that > > > explicit by whining when someone tries to flush one of the system wqs. > > > Here, the two cancel_delayed_work_sync() calls should be enough. > > > > Well, then I think this might be an issue for straightforward conversion > > of floppy driver to system_nrt_wq -- see floppy_grab_irq_and_dma(). > > Hmmm? flush_work() is fine. flush_workqueue() isn't. Am I missing > something? In floppy_grab_irq_and_dma() the point is to drain the workqueue completely (before the conversion, we were just using flush_work_sync(&floppy_work) for particular work item), and for that flush_work() is not sufficient any more. So I am really considering going back to driver-specific singlethreaded workqueue. Thanks, -- Jiri Kosina SUSE Labs -- 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/