On Thu, Jun 25, 2020 at 09:16:51PM +0530, Vinod Koul wrote:
> On partial_drain completion we should be in SNDRV_PCM_STATE_RUNNING
> state, so set that for partially draining streams in
> snd_compr_drain_notify() and use a flag for partially draining streams
>
> While at it, add locks for stream state change in
> snd_compr_drain_notify() as well.
>
> Fixes: f44f2a5417b2 ("ALSA: compress: fix drain calls blocking other compress functions (v6)")
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
> ---
> @@ -187,7 +189,15 @@ static inline void snd_compr_drain_notify(struct snd_compr_stream *stream)
> if (snd_BUG_ON(!stream))
> return;
>
> - stream->runtime->state = SNDRV_PCM_STATE_SETUP;
> + mutex_lock(&stream->device->lock);
> + /* for partial_drain case we are back to running state on success */
> + if (stream->partial_drain) {
> + stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
> + stream->partial_drain = false; /* clear this flag as well */
> + } else {
> + stream->runtime->state = SNDRV_PCM_STATE_SETUP;
> + }
> + mutex_unlock(&stream->device->lock);
You have added locking here in snd_compr_drain_notify but....
>
> wake_up(&stream->runtime->sleep);
> }
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> index e618580feac4..1c4b2cf450a0 100644
> --- a/sound/core/compress_offload.c
> +++ b/sound/core/compress_offload.c
> @@ -803,6 +803,9 @@ static int snd_compr_stop(struct snd_compr_stream *stream)
>
> retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP);
> if (!retval) {
> + /* clear flags and stop any drain wait */
> + stream->partial_drain = false;
> + stream->metadata_set = false;
> snd_compr_drain_notify(stream);
that can be called from snd_compr_stop here which is already
holding the lock resulting in deadlock.
Thanks,
Charles
