From patchwork Mon Feb 18 12:43:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 221297 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 2FA0E2C0B63 for ; Mon, 18 Feb 2013 23:48:18 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932173Ab3BRMqI (ORCPT ); Mon, 18 Feb 2013 07:46:08 -0500 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:35307 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757035Ab3BRMqD (ORCPT ); Mon, 18 Feb 2013 07:46:03 -0500 Received: from /spool/local by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 18 Feb 2013 22:36:54 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp04.au.ibm.com (202.81.31.210) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 18 Feb 2013 22:36:52 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 488EC2BB004F; Mon, 18 Feb 2013 23:45:57 +1100 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r1ICXUZr58851478; Mon, 18 Feb 2013 23:33:30 +1100 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r1ICjrRA022406; Mon, 18 Feb 2013 23:45:56 +1100 Received: from srivatsabhat.in.ibm.com (srivatsabhat.in.ibm.com [9.124.35.204] (may be forged)) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r1ICjlJi022322; Mon, 18 Feb 2013 23:45:48 +1100 From: "Srivatsa S. Bhat" Subject: [PATCH v6 40/46] powerpc: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, fweisbec@gmail.com, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, walken@google.com, vincent.guittot@linaro.org Date: Mon, 18 Feb 2013 18:13:51 +0530 Message-ID: <20130218124350.26245.49623.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130218123714.26245.61816.stgit@srivatsabhat.in.ibm.com> References: <20130218123714.26245.61816.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13021812-9264-0000-0000-0000032CB93B Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Srivatsa S. Bhat --- arch/powerpc/mm/mmu_context_nohash.c | 2 ++ 1 file changed, 2 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c index e779642..29f58cf 100644 --- a/arch/powerpc/mm/mmu_context_nohash.c +++ b/arch/powerpc/mm/mmu_context_nohash.c @@ -196,6 +196,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next) /* No lockless fast path .. yet */ raw_spin_lock(&context_lock); + get_online_cpus_atomic(); pr_hard("[%d] activating context for mm @%p, active=%d, id=%d", cpu, next, next->context.active, next->context.id); @@ -279,6 +280,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next) /* Flick the MMU and release lock */ pr_hardcont(" -> %d\n", id); set_context(id, next->pgd); + put_online_cpus_atomic(); raw_spin_unlock(&context_lock); }