+int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops) +{
- if (platform_ops)
return -EEXIST;- platform_ops = ops;
- return 0;
+} +EXPORT_SYMBOL_GPL(snd_usb_register_platform_ops);
+int snd_usb_unregister_platform_ops(void) +{
- platform_ops = NULL;
- return 0;
+} +EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);
I find this super-racy.
If the this function is called just before ...
/*
- disconnect streams
@@ -910,6 +928,10 @@ static int usb_audio_probe(struct usb_interface *intf, usb_set_intfdata(intf, chip); atomic_dec(&chip->active); mutex_unlock(®ister_mutex);
- if (platform_ops->connect_cb)
platform_ops->connect_cb(intf, chip);
... this, then you have a risk of using a dandling pointer.
You also didn't test that the platform_ops != NULL, so there's a risk of dereferencing a NULL pointer.
Not so good, eh?
It's a classic (I've had the same sort of issues with SoundWire), when you export ops from one driver than can be removed, then additional protection is needed when using those callbacks.