Takashi Iwai wrote:
> --- a/src/pcm/pcm.c
> +++ b/src/pcm/pcm.c
> @@ -686,6 +686,8 @@ snd_pcm_stream_t snd_pcm_stream(snd_pcm_t *pcm)
> *
> * Closes the specified PCM handle and frees all associated
> * resources.
> + *
> + * The function is thread-safe when built with the proper option.
> */
> int snd_pcm_close(snd_pcm_t *pcm)
> {
> @@ -697,6 +699,7 @@ int snd_pcm_close(snd_pcm_t *pcm)
> if (err < 0)
> res = err;
> }
> + snd_pcm_lock(pcm);
> if (pcm->mmap_channels)
> snd_pcm_munmap(pcm);
> while (!list_empty(&pcm->async_handlers)) {
> @@ -704,6 +707,7 @@ int snd_pcm_close(snd_pcm_t *pcm)
> snd_async_del_handler(h);
> }
> err = pcm->ops->close(pcm->op_arg);
> + snd_pcm_unlock(pcm);
> if (err < 0)
> res = err;
> err = snd_pcm_free(pcm);
Thread safety does not really make sense for a destructor like
snd_pcm_close(). If any other code is accessing the device at the same
time, the freeing will make it crash anyway.
What would make sense would be to output a debug warning if the device
is locked, and/or to poison the device (maybe ->ops = NULL).
Regards,
Clemens
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