From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752111Ab0FNLRj (ORCPT ); Mon, 14 Jun 2010 07:17:39 -0400 Received: from adelie.canonical.com ([91.189.90.139]:60097 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750831Ab0FNLRi (ORCPT ); Mon, 14 Jun 2010 07:17:38 -0400 Date: Mon, 14 Jun 2010 12:17:34 +0100 From: Andy Whitcroft To: Greg Kroah-Hartman , linux-usb@vger.kernel.org Cc: Inaky Perez-Gonzalez , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] UBUNTU: SAUCE: khubd -- switch USB product/manufacturer/serial handling to RCU Message-ID: <20100614111734.GT12061@shadowen.org> References: <1276514068-23668-1-git-send-email-apw@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1276514068-23668-1-git-send-email-apw@canonical.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 14, 2010 at 12:14:28PM +0100, Andy Whitcroft wrote: > With the introduction of wireless USB hubs the product, manufacturer, > and serial number are now mutable. This necessitates new locking in the > consumers of these values including the sysfs read routines in order to > prevent use-after-free acces to these values. These extra locks create > significant lock contention leading to increased boot times (0.3s for an > example Atom based system). Move update of these values to RCU based > locking. Bah, some Ubuntu-ism leaked out in the summary test, I've resent it with those removed. -apw