From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753010Ab0LUUTb (ORCPT ); Tue, 21 Dec 2010 15:19:31 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36419 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751223Ab0LUUTa (ORCPT ); Tue, 21 Dec 2010 15:19:30 -0500 Date: Tue, 21 Dec 2010 12:20:00 -0800 (PST) Message-Id: <20101221.122000.183069341.davem@davemloft.net> To: tj@kernel.org Cc: mchan@broadcom.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next-2.6] bnx2: remove cancel_work_sync() from remove_one From: David Miller In-Reply-To: <20101221105103.GA32744@htj.dyndns.org> References: <4D08C81D.8020606@kernel.org> <20101220.131146.115941299.davem@davemloft.net> <20101221105103.GA32744@htj.dyndns.org> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tejun Heo Date: Tue, 21 Dec 2010 11:51:04 +0100 > Yeah, I agree the synchronize_rcu() there would guarantee the actual > timer completion but as it currently stands it looks a bit too subtle. > Maybe it's a good idea to add a big fat comment explaining that the > the timer is guaranteed to stop after close() and how it's guaranteed > through synchronize_rcu() at the moment? Also, it might be better to > use synchronize_sched() there as timer synchronization through > synchronize_rcu() is more of a happy accident. I'm not sure the synchronize_*() is even necessary to guarentee watchdog timer completion. Like I said, I think the netif_tx_lock() held around both the timer function itself, and the del_timer() call, are sufficient. So, this ensures that the watchdog timer either runs to completion or sees the no-op scheduler attached and returns immediately without rescheduling the timer. In any event, I'm going to apply your bnx2 patch to net-next-2.6 Thanks.