On 07/26/2012 02:50 AM, Colin Cross wrote:
> The cpu hotplug notifier gets called in both atomic and non-atomic
> contexts, it is not always safe to lock a mutex. Filter out all events
> except the six necessary ones, which are all sleepable, before taking
> the mutex.
>
> Signed-off-by: Colin Cross <ccr...@android.com>
> ---
> drivers/cpuidle/coupled.c | 12 ++++++++++++
> 1 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
> index 2c9bf26..c24dda0 100644
> --- a/drivers/cpuidle/coupled.c
> +++ b/drivers/cpuidle/coupled.c
> @@ -678,6 +678,18 @@ static int cpuidle_coupled_cpu_notify(struct
> notifier_block *nb,
> int cpu = (unsigned long)hcpu;
> struct cpuidle_device *dev;
>
> + switch (action & ~CPU_TASKS_FROZEN) {
> + case CPU_UP_PREPARE:
> + case CPU_DOWN_PREPARE:
> + case CPU_ONLINE:
> + case CPU_DEAD:
> + case CPU_UP_CANCELED:
> + case CPU_DOWN_FAILED:
> + break;
> + default:
> + return NOTIFY_OK;
> + }
> +
Instead, wouldn't it be better to have case statements for the
2 cases that imply atomic context and return immediately?
Something like:
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
case CPU_DYING:
return NOTIFY_OK;
}
Regards,
Srivatsa S. Bhat
> mutex_lock(&cpuidle_lock);
>
> dev = per_cpu(cpuidle_devices, cpu);
>
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