[alsa-devel] [PATCH] compress: add support for gapless playback

[Vinod Koul]

On Wed, Feb 13, 2013 at 05:40:11PM +0100, Takashi Iwai wrote:
> At Wed, 13 Feb 2013 08:00:34 -0800,
> Vinod Koul wrote:
> > 
> > +static int
> > +snd_compr_get_metadata(struct snd_compr_stream *stream, unsigned long arg)
> > +{
> > +	struct snd_compr_metadata *metadata;
> > +	int retval;
> > +
> > +	if (!stream->ops->get_metadata)
> > +		return -ENXIO;
> > +
> > +	metadata = kmalloc(sizeof(*metadata), GFP_KERNEL);
> 
> There is no merit to use kmalloc just for two integers at all.
> Simply put on stack:
> 	struct snd_compr_metadata metdata;
> 	if (copy_from_user(&metadata, (void __user *)arg, sizeof(metadata)))
> 	...
while doing this I had thought on this, but my laziness got better of me :(
> 
> Ditto for snd_compr_set_metadata().
> 
> > +static int snd_compr_partial_drain(struct snd_compr_stream *stream)
> > +{
> > +	int retval;
> > +	if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||
> > +			stream->runtime->state == SNDRV_PCM_STATE_SETUP)
> > +		return -EPERM;
> > +	/* stream can be drained only when next track has been signalled */
> > +	if (stream->next_track == false)
> > +		return -EPERM;
> > +
> > +	retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_PARTIAL_DRAIN);
> > +	if (retval)
> > +		pr_err("Partial drain returned failure\n");
> 
> I don't think it's good to spew errors.
ok
> 
> Also, the initialization of new stream fields is missing in other
> places like prepare callback?  Otherwise the values will retain.
The stream is created at open. Since it used kzalloc, these variables would be
init to false.

--
~Vinod