Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936Ab2E2IRl (ORCPT ); Tue, 29 May 2012 04:17:41 -0400 Received: from shards.monkeyblade.net ([198.137.202.13]:54546 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752843Ab2E2IRi (ORCPT ); Tue, 29 May 2012 04:17:38 -0400 Date: Tue, 29 May 2012 04:14:58 -0400 (EDT) Message-Id: <20120529.041458.1686171726483755640.davem@davemloft.net> To: srivatsa.bhat@linux.vnet.ibm.com Cc: yong.zhang0@gmail.com, linux-kernel@vger.kernel.org, ralf@linux-mips.org, sshtylyov@mvista.com, david.daney@cavium.com, nikunj@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, axboe@kernel.dk, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, akpm@linux-foundation.org, sparclinux@vger.kernel.org Subject: Re: [PATCH 08/10] SPARC: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() From: David Miller In-Reply-To: <4FC48272.9040904@linux.vnet.ibm.com> References: <1338275765-3217-1-git-send-email-yong.zhang0@gmail.com> <1338275765-3217-9-git-send-email-yong.zhang0@gmail.com> <4FC48272.9040904@linux.vnet.ibm.com> X-Mailer: Mew version 6.5 on Emacs 24.0.95 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (shards.monkeyblade.net [198.137.202.13]); Tue, 29 May 2012 01:15:05 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1863 Lines: 47 From: "Srivatsa S. Bhat" Date: Tue, 29 May 2012 13:31:54 +0530 > On 05/29/2012 12:46 PM, Yong Zhang wrote: > >> From: Yong Zhang >> >> 1) call_function.lock used in smp_call_function_many() is just to protect >> call_function.queue and &data->refs, cpu_online_mask is outside of the >> lock. And it's not necessary to protect cpu_online_mask, >> because data->cpumask is pre-calculate and even if a cpu is brougt up >> when calling arch_send_call_function_ipi_mask(), it's harmless because >> validation test in generic_smp_call_function_interrupt() will take care >> of it. >> >> 2) For cpu down issue, stop_machine() will guarantee that no concurrent >> smp_call_fuction() is processing. >> >> Signed-off-by: Yong Zhang >> Cc: "David S. Miller" >> Cc: sparclinux@vger.kernel.org >> --- >> arch/sparc/kernel/smp_64.c | 6 ++---- >> 1 files changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c >> index f591598..60e745c 100644 >> --- a/arch/sparc/kernel/smp_64.c >> +++ b/arch/sparc/kernel/smp_64.c >> @@ -124,9 +124,9 @@ void __cpuinit smp_callin(void) >> while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) >> rmb(); >> >> - ipi_call_lock_irq(); >> + local_irq_disable(); > > > This looks odd. IRQs must not have been enabled at this point. > Just remove the call to local_irq_enable() that is found a few lines above > this line and then you won't have to add this call to local_irq_disable(). Agreed. -- 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/