Re: [RFC PATCH v9 6/9] media: tegra: Add Tegra210 Video input driver

[Dmitry Osipenko]

24.04.2020 02:20, Sowjanya Komatineni ÐÐÑÐÑ:
> 
> On 4/23/20 4:19 PM, Sowjanya Komatineni wrote:
>>
>> On 4/23/20 4:16 PM, Dmitry Osipenko wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> 22.04.2020 09:18, 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 set_freezable();
>>>> +
>>>> +ÂÂÂÂ while (1) {
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ try_to_freeze();
>>>> +
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ wait_event_interruptible(chan->start_wait,
>>>> + !list_empty(&chan->capture) ||
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ kthread_should_stop());
>>>> +
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ if (kthread_should_stop())
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ break;
>>>> +
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ /*
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ * Source is not streaming if error is non-zero.
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ * So, do not dequeue buffers on capture error.
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ */
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ if (err)
>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ continue;
>>> This will result in an endless loop, I suppose it wasn't the intention.
>>
>> no it will not. on error we report vb2_queue_error which will do
>> streaming stop request.
>>
>> So thread will be stopped on streaming stop request thru kthread stop
>> signal
> To be clear on error it reports vb2 queue error and waits for stop
> streaming to happen

If thread should exit on error, then it should do it on the actual
error. Otherwise it looks very error-prone.