Re: [PATCH 2/3] power: increment wakeup_count when save_wakeup_count failed.

From: Pavel Machek
Date: Sat Apr 25 2015 - 16:10:55 EST


On Wed 2015-04-22 17:50:11, Jin Qian wrote:
> user-space aborts suspend attempt if writing wakeup_count failed.
> Count the write failure towards wakeup_count.

Why should writing wakeup_count fail? Can you make sure it does not
happen, instead?
Pavel

> Signed-off-by: Jin Qian <jinqian@xxxxxxxxxxx>
> ---
> drivers/base/power/wakeup.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index f24c622..bdb45f3 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -57,6 +57,8 @@ static LIST_HEAD(wakeup_sources);
>
> static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
>
> +static ktime_t last_read_time;
> +
> /**
> * wakeup_source_prepare - Prepare a new wakeup source for initialization.
> * @ws: Wakeup source to prepare.
> @@ -771,10 +773,15 @@ void pm_wakeup_clear(void)
> bool pm_get_wakeup_count(unsigned int *count, bool block)
> {
> unsigned int cnt, inpr;
> + unsigned long flags;
>
> if (block) {
> DEFINE_WAIT(wait);
>
> + spin_lock_irqsave(&events_lock, flags);
> + last_read_time = ktime_get();
> + spin_unlock_irqrestore(&events_lock, flags);
> +
> for (;;) {
> prepare_to_wait(&wakeup_count_wait_queue, &wait,
> TASK_INTERRUPTIBLE);
> @@ -806,6 +813,7 @@ bool pm_save_wakeup_count(unsigned int count)
> {
> unsigned int cnt, inpr;
> unsigned long flags;
> + struct wakeup_source *ws;
>
> events_check_enabled = false;
> spin_lock_irqsave(&events_lock, flags);
> @@ -813,6 +821,15 @@ bool pm_save_wakeup_count(unsigned int count)
> if (cnt == count && inpr == 0) {
> saved_count = count;
> events_check_enabled = true;
> + } else {
> + rcu_read_lock();
> + list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
> + if (ws->active ||
> + ktime_compare(ws->last_time, last_read_time) > 0) {
> + ws->wakeup_count++;
> + }
> + }
> + rcu_read_unlock();
> }
> spin_unlock_irqrestore(&events_lock, flags);
> return events_check_enabled;

--
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