diff options
| author | Ingo Molnar <mingo@elte.hu> | 2009-07-03 13:30:27 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2014-04-10 00:19:13 (GMT) |
| commit | 0beecd3a9e60f7d0aabbd36b40785ac40bd7913f (patch) | |
| tree | d2e4063977f2ded2c5fe5c9d78e4ab8b0f2cc4a5 /kernel/stop_machine.c | |
| parent | a6e1de1a21be70d251a0d2e017b062141c58bc85 (diff) | |
| download | linux-fsl-qoriq-0beecd3a9e60f7d0aabbd36b40785ac40bd7913f.tar.xz | |
stop_machine: convert stop_machine_run() to PREEMPT_RT
Instead of playing with non-preemption, introduce explicit
startup serialization. This is more robust and cleaner as
well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/stop_machine.c')
| -rw-r--r-- | kernel/stop_machine.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index c09f295..51f8088 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -137,6 +137,7 @@ void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg, /* static data for stop_cpus */ static DEFINE_MUTEX(stop_cpus_mutex); +static DEFINE_MUTEX(stopper_lock); static DEFINE_PER_CPU(struct cpu_stop_work, stop_cpus_work); static void queue_stop_cpus_work(const struct cpumask *cpumask, @@ -155,14 +156,13 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask, } /* - * Disable preemption while queueing to avoid getting - * preempted by a stopper which might wait for other stoppers - * to enter @fn which can lead to deadlock. + * Make sure that all work is queued on all cpus before we + * any of the cpus can execute it. */ - preempt_disable(); + mutex_lock(&stopper_lock); for_each_cpu(cpu, cpumask) cpu_stop_queue_work(cpu, &per_cpu(stop_cpus_work, cpu)); - preempt_enable(); + mutex_unlock(&stopper_lock); } static int __stop_cpus(const struct cpumask *cpumask, @@ -279,6 +279,16 @@ repeat: struct cpu_stop_done *done = work->done; char ksym_buf[KSYM_NAME_LEN] __maybe_unused; + /* + * Wait until the stopper finished scheduling on all + * cpus + */ + mutex_lock(&stopper_lock); + /* + * Let other cpu threads continue as well + */ + mutex_unlock(&stopper_lock); + /* cpu stop callbacks are not allowed to sleep */ preempt_disable(); |