From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp04.in.ibm.com (e28smtp04.in.ibm.com [122.248.162.4]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp04.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 0F93C2C05E5 for ; Wed, 26 Jun 2013 06:31:40 +1000 (EST) Received: from /spool/local by e28smtp04.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Jun 2013 01:55:24 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 882F91258051 for ; Wed, 26 Jun 2013 02:00:40 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5PKVXPI23593204 for ; Wed, 26 Jun 2013 02:01:33 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5PKVYLf009330 for ; Wed, 26 Jun 2013 06:31:36 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH v2 17/45] time/clocksource: 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 01:58:20 +0530 Message-ID: <20130625202820.16593.17778.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, 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, John Stultz , wangyun@linux.vnet.ibm.com, "Srivatsa S. Bhat" , netdev@vger.kernel.org, Thomas Gleixner , linuxppc-dev@lists.ozlabs.org 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: John Stultz Cc: Thomas Gleixner Signed-off-by: Srivatsa S. Bhat --- kernel/time/clocksource.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index e713ef7..c4bbc25 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -30,6 +30,7 @@ #include /* for spin_unlock_irq() using preempt_count() m68k */ #include #include +#include #include "tick-internal.h" @@ -252,6 +253,7 @@ static void clocksource_watchdog(unsigned long data) int64_t wd_nsec, cs_nsec; int next_cpu, reset_pending; + get_online_cpus_atomic(); spin_lock(&watchdog_lock); if (!watchdog_running) goto out; @@ -329,6 +331,7 @@ static void clocksource_watchdog(unsigned long data) add_timer_on(&watchdog_timer, next_cpu); out: spin_unlock(&watchdog_lock); + put_online_cpus_atomic(); } static inline void clocksource_start_watchdog(void) @@ -367,6 +370,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs) { unsigned long flags; + get_online_cpus_atomic(); spin_lock_irqsave(&watchdog_lock, flags); if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { /* cs is a clocksource to be watched. */ @@ -386,6 +390,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs) /* Check if the watchdog timer needs to be started. */ clocksource_start_watchdog(); spin_unlock_irqrestore(&watchdog_lock, flags); + put_online_cpus_atomic(); } static void clocksource_dequeue_watchdog(struct clocksource *cs)