From patchwork Tue Jan 22 07:38:42 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: 2016731 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id E5B423FCDE for ; Tue, 22 Jan 2013 07:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754749Ab3AVHkq (ORCPT ); Tue, 22 Jan 2013 02:40:46 -0500 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:51246 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754407Ab3AVHko (ORCPT ); Tue, 22 Jan 2013 02:40:44 -0500 Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 22 Jan 2013 13:08:40 +0530 Received: from d28dlp03.in.ibm.com (9.184.220.128) by e28smtp02.in.ibm.com (192.168.1.132) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 22 Jan 2013 13:08:36 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 812BF1258056; Tue, 22 Jan 2013 13:11:01 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0M7eagc59965464; Tue, 22 Jan 2013 13:10:36 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0M7eU5A017442; Tue, 22 Jan 2013 18:40:37 +1100 Received: from srivatsabhat.in.ibm.com (srivatsabhat.in.ibm.com [9.124.35.112]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r0M7eSP7017314; Tue, 22 Jan 2013 18:40:28 +1100 From: "Srivatsa S. Bhat" Subject: [PATCH v5 20/45] 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 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 Date: Tue, 22 Jan 2013 13:08:42 +0530 Message-ID: <20130122073838.13822.28777.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012207-5816-0000-0000-0000065BDF02 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@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: Jens Axboe Signed-off-by: Srivatsa S. Bhat --- block/blk-softirq.c | 4 ++++ 1 file changed, 4 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" 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/block/blk-softirq.c b/block/blk-softirq.c index 467c8de..448f9a9 100644 --- a/block/blk-softirq.c +++ b/block/blk-softirq.c @@ -58,6 +58,8 @@ 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; @@ -66,9 +68,11 @@ 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; } #else /* CONFIG_SMP && CONFIG_USE_GENERIC_SMP_HELPERS */