From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753525Ab3BDKsi (ORCPT ); Mon, 4 Feb 2013 05:48:38 -0500 Received: from www.linutronix.de ([62.245.132.108]:42990 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660Ab3BDKsh (ORCPT ); Mon, 4 Feb 2013 05:48:37 -0500 Date: Mon, 4 Feb 2013 11:48:24 +0100 (CET) From: Thomas Gleixner To: Paul Gortmaker cc: Grant Likely , Rob Herring , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH] OF: Fixup resursive locking code paths In-Reply-To: <1359138107-14159-1-git-send-email-paul.gortmaker@windriver.com> Message-ID: References: <1359138107-14159-1-git-send-email-paul.gortmaker@windriver.com> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 25 Jan 2013, Paul Gortmaker wrote: > From: Thomas Gleixner > > There is no real reason to use a rwlock for devtree_lock. It even > could be a mutex, but unfortunately it's locked from cpu hotplug > paths which can't schedule :( > > So it needs to become a raw lock on rt as well. The devtree_lock would > be the only user of a raw_rw_lock, so we are better off cleaning up the > recursive locking paths which allows us to convert devtree_lock to a > read_lock. Hmm. It's already a rw_lock. For RT we want to change that thing to a raw_spinlock. Thanks, tglx