Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262857AbUCJVnb (ORCPT ); Wed, 10 Mar 2004 16:43:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262855AbUCJVnQ (ORCPT ); Wed, 10 Mar 2004 16:43:16 -0500 Received: from uucp.cistron.nl ([62.216.30.38]:4078 "EHLO ncc1701.cistron.net") by vger.kernel.org with ESMTP id S262854AbUCJVkw (ORCPT ); Wed, 10 Mar 2004 16:40:52 -0500 From: "Miquel van Smoorenburg" Subject: Re: [PATCH] backing dev unplugging Date: Wed, 10 Mar 2004 21:40:50 +0000 (UTC) Organization: Cistron Group Message-ID: References: <20040310124507.GU4949@suse.de> <20040310130046.2df24f0e.akpm@osdl.org> <20040310210207.GL15087@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Trace: ncc1701.cistron.net 1078954850 4640 62.216.29.200 (10 Mar 2004 21:40:50 GMT) X-Complaints-To: abuse@cistron.nl X-Newsreader: trn 4.0-test76 (Apr 2, 2001) Originator: miquels@cistron-office.nl (Miquel van Smoorenburg) To: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 870 Lines: 23 In article <20040310210207.GL15087@suse.de>, Jens Axboe wrote: >On Wed, Mar 10 2004, Andrew Morton wrote: >> Jens Axboe wrote: >> > >> > Here's a first cut at killing global plugging of block devices to reduce >> > the nasty contention blk_plug_lock caused. >> >> Shouldn't we take read_lock(&md->map_lock) in dm_table_unplug_all()? > >Ugh yes, we certainly should. With the latest patches from Joe it would be more like map = dm_get_table(md); if (map) { dm_table_unplug_all(map); dm_table_put(map); } No lock ranking issues, you just get a refcounted map (table, really). Mike. - 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/