From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp04.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id D7A6A2C094C for ; Wed, 26 Jun 2013 06:34:32 +1000 (EST) Received: from /spool/local by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Jun 2013 06:20:01 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 1B3342BB0053 for ; Wed, 26 Jun 2013 06:34:29 +1000 (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 r5PKJU154784472 for ; Wed, 26 Jun 2013 06:19:30 +1000 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 r5PKYQqo032344 for ; Wed, 26 Jun 2013 06:34:28 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH v2 30/45] x86/xen: 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, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Date: Wed, 26 Jun 2013 02:00:57 +0530 Message-ID: <20130625203057.16593.50205.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> References: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: linux-arch@vger.kernel.org, Jeremy Fitzhardinge , x86@kernel.org, "H. Peter Anvin" , nikunj@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, Ingo Molnar , wangyun@linux.vnet.ibm.com, "Srivatsa S. Bhat" , netdev@vger.kernel.org, Thomas Gleixner , virtualization@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xensource.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption 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: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Signed-off-by: Srivatsa S. Bhat --- arch/x86/xen/mmu.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index fdc3ba2..3229c4f 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -39,6 +39,7 @@ * Jeremy Fitzhardinge , XenSource Inc, 2007 */ #include +#include #include #include #include @@ -1163,9 +1164,13 @@ static void xen_drop_mm_ref(struct mm_struct *mm) */ static void xen_exit_mmap(struct mm_struct *mm) { - get_cpu(); /* make sure we don't move around */ + /* + * Make sure we don't move around, and also prevent CPUs from + * going offline. + */ + get_online_cpus_atomic(); xen_drop_mm_ref(mm); - put_cpu(); + put_online_cpus_atomic(); spin_lock(&mm->page_table_lock);