Re: [RFC PATCH v6 6/9] media: tegra: Add Tegra210 Video input driver

[Dmitry Osipenko]

06.04.2020 23:20, Sowjanya Komatineni ÐÐÑÐÑ:
> 
> On 4/6/20 1:02 PM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> 04.04.2020 04:25, Sowjanya Komatineni ÐÐÑÐÑ:
>> ...
>>> +static int chan_capture_kthread_start(void *data)
>>> +{
>>> +ÂÂÂÂ struct tegra_vi_channel *chan = data;
>>> +ÂÂÂÂ struct tegra_channel_buffer *buf;
>>> +ÂÂÂÂ int err = 0;
>>> +ÂÂÂÂ int caps_inflight;
>>> +
>>> +ÂÂÂÂ set_freezable();
>>> +
>>> +ÂÂÂÂ while (1) {
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ try_to_freeze();
>>> +
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ wait_event_interruptible(chan->start_wait,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ !list_empty(&chan->capture) ||
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ kthread_should_stop());
>> Is it really okay that list_empty() isn't protected with a lock?
>>
>> Why wait_event is "interruptible"?
> 
> To allow it to sleep until wakeup on thread it to avoid constant
> checking for condition even when no buffers are ready, basically to
> prevent blocking.

So the "interrupt" is for getting event about kthread_should_stop(),
correct?