[alsa-devel] [PATCH 3/3] sound: dummy, avoid races with timer

[Jiri Slaby]

On 01/19/2015, 10:49 AM, Takashi Iwai wrote:
>> @@ -322,12 +325,14 @@ static snd_pcm_uframes_t
>>  dummy_systimer_pointer(struct snd_pcm_substream *substream)
>>  {
>>  	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
>> +	unsigned long flags;
>>  	snd_pcm_uframes_t pos;
>>  
>> -	spin_lock(&dpcm->lock);
>> +	spin_lock_irqsave(&dpcm->lock, flags);
>>  	dummy_systimer_update(dpcm);
>>  	pos = dpcm->frac_pos / HZ;
>> -	spin_unlock(&dpcm->lock);
>> +	spin_unlock_irqrestore(&dpcm->lock, flags);
>> +
> 
> This chunk is superfluous.  The pointer callback is guaranteed to be
> called in the irq-disabled context.

Oh, my bad, I was looking at snd_compr_ops->pointer which is not the case.

-- 
js
suse labs