From patchwork Thu Jun 27 19:56:35 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: 255198 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id B05D02C1862 for ; Fri, 28 Jun 2013 06:15:29 +1000 (EST) Received: from e28smtp06.in.ibm.com (e28smtp06.in.ibm.com [122.248.162.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp06.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id C2CF42C04FA for ; Fri, 28 Jun 2013 05:59:57 +1000 (EST) Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 28 Jun 2013 01:22:22 +0530 Received: from d28dlp03.in.ibm.com (9.184.220.128) by e28smtp06.in.ibm.com (192.168.1.136) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Fri, 28 Jun 2013 01:22:19 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id E5C2C1258043 for ; Fri, 28 Jun 2013 01:28:56 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5RK0AZi28442708 for ; Fri, 28 Jun 2013 01:30:10 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5RJxooo019988 for ; Fri, 28 Jun 2013 05:59:51 +1000 Received: from srivatsabhat.in.ibm.com ([9.79.209.72]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r5RJxmEI019944; Fri, 28 Jun 2013 05:59:49 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH v3 22/45] block: 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, David.Laight@aculab.com Date: Fri, 28 Jun 2013 01:26:35 +0530 Message-ID: <20130627195634.29830.41449.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130627195136.29830.10445.stgit@srivatsabhat.in.ibm.com> References: <20130627195136.29830.10445.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062719-9574-0000-0000-0000087DBADB Cc: linux-arch@vger.kernel.org, Jens Axboe , nikunj@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, wangyun@linux.vnet.ibm.com, "Srivatsa S. Bhat" , netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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: Jens Axboe Signed-off-by: Srivatsa S. Bhat --- block/blk-softirq.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/blk-softirq.c b/block/blk-softirq.c index 467c8de..bbab3d3 100644 --- a/block/blk-softirq.c +++ b/block/blk-softirq.c @@ -58,6 +58,7 @@ static void trigger_softirq(void *data) */ static int raise_blk_irq(int cpu, struct request *rq) { + get_online_cpus_atomic(); if (cpu_online(cpu)) { struct call_single_data *data = &rq->csd; @@ -66,8 +67,10 @@ static int raise_blk_irq(int cpu, struct request *rq) data->flags = 0; __smp_call_function_single(cpu, data, 0); + put_online_cpus_atomic(); return 0; } + put_online_cpus_atomic(); return 1; }