From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757486AbZCMBkw (ORCPT ); Thu, 12 Mar 2009 21:40:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751172AbZCMBkn (ORCPT ); Thu, 12 Mar 2009 21:40:43 -0400 Received: from hera.kernel.org ([140.211.167.34]:46611 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852AbZCMBkm (ORCPT ); Thu, 12 Mar 2009 21:40:42 -0400 Date: Fri, 13 Mar 2009 01:39:23 GMT From: Jan Beulich To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, jbeulich@novell.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, jbeulich@novell.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <49B91A7E.76E4.0078.0@novell.com> References: <49B91A7E.76E4.0078.0@novell.com> Subject: [tip:core/ipi] generic-ipi: eliminate spurious pointless WARN_ON()s Message-ID: Git-Commit-ID: 6a09dfa870ba0ed21b1124539968a36b42660661 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 13 Mar 2009 01:39:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6a09dfa870ba0ed21b1124539968a36b42660661 Gitweb: http://git.kernel.org/tip/6a09dfa870ba0ed21b1124539968a36b42660661 Author: Jan Beulich AuthorDate: Thu, 12 Mar 2009 13:21:50 +0000 Commit: Ingo Molnar CommitDate: Fri, 13 Mar 2009 02:14:41 +0100 generic-ipi: eliminate spurious pointless WARN_ON()s Namely during early boot, the panic() or BUG() paths may end up in smp_call_function_*() with just a single online CPU. In that situation the warnings generated are not only meaningless, but also result in relevant output being cluttered. Therefore, defer the WARN_ON() checks until after the (unaffected from the problem that is being attempted to be detected here) cases have been handled. Signed-off-by: Jan Beulich LKML-Reference: <49B91A7E.76E4.0078.0@novell.com> Signed-off-by: Ingo Molnar --- kernel/smp.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/smp.c b/kernel/smp.c index 7ad2262..37b90a9 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -284,9 +284,6 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, */ this_cpu = get_cpu(); - /* Can deadlock when called with interrupts disabled */ - WARN_ON(irqs_disabled()); - if (cpu == this_cpu) { local_irq_save(flags); func(info); @@ -295,6 +292,9 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { struct call_single_data *data = &d; + /* Can deadlock when called with interrupts disabled */ + WARN_ON(irqs_disabled()); + if (!wait) data = &__get_cpu_var(csd_data); @@ -364,9 +364,6 @@ void smp_call_function_many(const struct cpumask *mask, unsigned long flags; int cpu, next_cpu, this_cpu = smp_processor_id(); - /* Can deadlock when called with interrupts disabled */ - WARN_ON(irqs_disabled()); - /* So, what's a CPU they want? Ignoring this one. */ cpu = cpumask_first_and(mask, cpu_online_mask); if (cpu == this_cpu) @@ -387,6 +384,9 @@ void smp_call_function_many(const struct cpumask *mask, return; } + /* Can deadlock when called with interrupts disabled */ + WARN_ON(irqs_disabled()); + data = &__get_cpu_var(cfd_data); csd_lock(&data->csd);