From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271144AbTHCKMQ (ORCPT ); Sun, 3 Aug 2003 06:12:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271146AbTHCKMQ (ORCPT ); Sun, 3 Aug 2003 06:12:16 -0400 Received: from AMarseille-201-1-2-252.w193-253.abo.wanadoo.fr ([193.253.217.252]:28711 "EHLO gaston") by vger.kernel.org with ESMTP id S271144AbTHCKMM (ORCPT ); Sun, 3 Aug 2003 06:12:12 -0400 Subject: Re: IDE locking problem From: Benjamin Herrenschmidt To: Jens Axboe Cc: linux-kernel mailing list In-Reply-To: <20030803100447.GO7920@suse.de> References: <1059900149.3524.84.camel@gaston> <20030803100447.GO7920@suse.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1059905514.3514.111.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.3 Date: 03 Aug 2003 12:11:54 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > would help making sure we don't get a request sneaking in ? > > Hmm not really, there's still a chance that could happen. Not too familiar with BIO here, but we would need some kind of "dead" flag to cause a reject of any try to insert a new request in the queue, don't you think ? Then, IDE could do something like: - set dead flag - wait for all pending requests to drain (easy: insert a barrier in the queue and wait on it, with a hack for the barrier insertion to bypass the dead flag... ugh... maybe a blk_terminate_queue() doing all that would be helpful ?) - unregister blkdev - then tear down the queue (leaving the "empty" queue with the dead flag set, not just memset(...,0,...), so that any bozo keeping a reference to it will be rejected trying to insert request instead of trying to tap an uninitalized queue object What do you think ? Ben.