Re: [PATCH][RFC] ASoC: soc-component: count snd_soc_component_open/close()

On Wed, Feb 19, 2020 at 5:42 PM Kuninori Morimoto < kuninori.morimoto.gx@renesas.com> wrote:

Hi Sridharan

...

ASoC component open/close and snd_soc_component_module_get/put are
called once for each component, but we need it for each substream.
To solve this issue, this patch counts open / get,
and call close / put accordingly.

Fixes: dd03907bf129 ("ASoC: soc-pcm: call

snd_soc_component_open/close() once")

...

Reported-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---

(snip)

...

@@ -297,14 +297,16 @@ EXPORT_SYMBOL_GPL(snd_soc_component_set_jack);
 int snd_soc_component_module_get(struct snd_soc_component

*component,

...

                                 int upon_open)
 {
-       if (component->module)
-               return 0;
+       if (unlikely(component->module == 0xff)) {
+               dev_warn(component->dev, "too many module get

(%s)\n", component->name);

...

+               return -EBUSY;
+       }

        if (component->driver->module_get_upon_open == !!upon_open &&
            !try_module_get(component->dev->driver->owner))
                return -ENODEV;

-       component->module = 1;
+       component->module++;

Thanks, Morimoto-san for the alternate fix. I understand the rationale

for having a count for component->opened, but what is the rationale for the module count? What it is

...

intended to protect?

I think same as open ? It protects calling put() from not-get-component. Because module_put() has WARN_ON(ret < 0).

Can we use the module_refcount instead of adding a new field?

Thanks, Ranjani