Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752002Ab1CBFXY (ORCPT ); Wed, 2 Mar 2011 00:23:24 -0500 Received: from mail-qy0-f181.google.com ([209.85.216.181]:49199 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918Ab1CBFXY (ORCPT ); Wed, 2 Mar 2011 00:23:24 -0500 Date: Tue, 1 Mar 2011 23:23:20 -0600 From: Shaun Ruffell To: "Eric W. Biederman" Cc: Andrew Morton , Russ Meyerriecks , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Greg KH Subject: Re: [PATCH] mm/dmapool.c: Do not create/destroy sysfs file while holding pools_lock Message-ID: <20110302052320.GB7463@kilby.digium.internal> References: <20110228224124.GA31769@blackmagic.digium.internal> <20110301170117.258e06e2.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1088 Lines: 33 On Tue, Mar 01, 2011 at 08:35:53PM -0800, Eric W. Biederman wrote: > Andrew Morton writes: > > One way of fixing this would be to create another singleton lock: > > > > > > { > > static DEFINE_MUTEX(pools_sysfs_lock); > > static bool pools_sysfs_done; > > > > mutex_lock(&pools_sysfs_lock); > > if (pools_sysfs_done == false) { > > create_sysfs_stuff(); > > pools_sysfs_done = true; > > } > > mutex_unlock(&pools_sysfs_lock); > > } > > > > That's not terribly pretty. > > Or possibly use module_init style magic. Where use module > initialization and remove to trigger creation and deletion of the sysfs. > I'm not following how module initialization can help here. Are you suggesting that all devices get a 'pools' attribute regardless of whether any dma pools are actually created? Shaun -- 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/