Re: [PATCH 1/2] ALSA: core: add snd_device_init

[Takashi Iwai <tiwai@suse.de>]

On Thu, 24 Aug 2023 23:02:52 +0200,
cujomalainey@chromium.org wrote:
> 
> From: Curtis Malainey <cujomalainey@chromium.org>
> 
> Begin allowing refactored modules to allocate their own device but use a
> common initialization procedure for their devices.
> 
> Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
> ---
>  include/sound/core.h |  1 +
>  sound/core/init.c    | 19 ++++++++++++++++---
>  2 files changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/include/sound/core.h b/include/sound/core.h
> index dfef0c9d4b9f7..a4744e142c7e3 100644
> --- a/include/sound/core.h
> +++ b/include/sound/core.h
> @@ -240,6 +240,7 @@ extern struct dentry *sound_debugfs_root;
>  void snd_request_card(int card);
>  
>  int snd_device_alloc(struct device **dev_p, struct snd_card *card);
> +void snd_device_init(struct device *dev, struct snd_card *card);
>  
>  int snd_register_device(int type, struct snd_card *card, int dev,
>  			const struct file_operations *f_ops,
> diff --git a/sound/core/init.c b/sound/core/init.c
> index d61bde1225f23..37a8e4791f781 100644
> --- a/sound/core/init.c
> +++ b/sound/core/init.c
> @@ -132,15 +132,28 @@ int snd_device_alloc(struct device **dev_p, struct snd_card *card)
>  	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
>  	if (!dev)
>  		return -ENOMEM;
> +	snd_device_init(dev, card);
> +	*dev_p = dev;
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(snd_device_alloc);
> +
> +/**
> + * snd_device_init - Initialize struct device for sound devices
> + * @dev_p: pointer to store the allocated device
> + * @card: card to assign, optional
> + *
> + * For releasing the allocated device, call put_device().
> + */
> +void snd_device_init(struct device *dev, struct snd_card *card)
> +{
>  	device_initialize(dev);
>  	if (card)
>  		dev->parent = &card->card_dev;
>  	dev->class = &sound_class;
>  	dev->release = default_release_alloc;
> -	*dev_p = dev;
> -	return 0;
>  }
> -EXPORT_SYMBOL_GPL(snd_device_alloc);
> +EXPORT_SYMBOL_GPL(snd_device_init);

This will call kfree() at the default release.  It should be avoided
for this case, no?

Also, it's worth that this practically a kind of revive of the old API
that was dropped in the commit 01ed7f3535a2.


thanks,

Takashi