Re: [PATCH v2 01/10] fpga: fpga-mgr: Add devm_fpga_mgr_register() API

[Moritz Fischer <mdf@kernel.org>]

On Mon, Oct 05, 2020 at 10:37:26AM -0700, Moritz Fischer wrote:
> Add a devm_fpga_mgr_register() API that can be used to register a FPGA
> Manager that was created using devm_fpga_mgr_create().
> 
> Introduce a struct fpga_mgr_devres that makes the devres
> allocation a little bit more readable and gets reused for
> devm_fpga_mgr_create() devm_fpga_mgr_register().
> 
> Reviewed-by: Tom Rix <trix@redhat.com>
> Signed-off-by: Moritz Fischer <mdf@kernel.org>
> ---
>  drivers/fpga/fpga-mgr.c       | 81 +++++++++++++++++++++++++++++------
>  include/linux/fpga/fpga-mgr.h |  2 +
>  2 files changed, 71 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> index f38bab01432e..b85bc47c91a9 100644
> --- a/drivers/fpga/fpga-mgr.c
> +++ b/drivers/fpga/fpga-mgr.c
> @@ -21,6 +21,10 @@
>  static DEFINE_IDA(fpga_mgr_ida);
>  static struct class *fpga_mgr_class;
>  
> +struct fpga_mgr_devres {
> +	struct fpga_manager *mgr;
> +};
> +
>  /**
>   * fpga_image_info_alloc - Allocate a FPGA image info struct
>   * @dev: owning device
> @@ -625,9 +629,9 @@ EXPORT_SYMBOL_GPL(fpga_mgr_free);
>  
>  static void devm_fpga_mgr_release(struct device *dev, void *res)
>  {
> -	struct fpga_manager *mgr = *(struct fpga_manager **)res;
> +	struct fpga_mgr_devres *dr = res;
>  
> -	fpga_mgr_free(mgr);
> +	fpga_mgr_free(dr->mgr);
>  }
>  
>  /**
> @@ -651,21 +655,21 @@ struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name,
>  					  const struct fpga_manager_ops *mops,
>  					  void *priv)
>  {
> -	struct fpga_manager **ptr, *mgr;
> +	struct fpga_mgr_devres *dr;
>  
> -	ptr = devres_alloc(devm_fpga_mgr_release, sizeof(*ptr), GFP_KERNEL);
> -	if (!ptr)
> +	dr = devres_alloc(devm_fpga_mgr_release, sizeof(*dr), GFP_KERNEL);
> +	if (!dr)
>  		return NULL;
>  
> -	mgr = fpga_mgr_create(dev, name, mops, priv);
> -	if (!mgr) {
> -		devres_free(ptr);
> -	} else {
> -		*ptr = mgr;
> -		devres_add(dev, ptr);
> +	dr->mgr = fpga_mgr_create(dev, name, mops, priv);
> +	if (!dr->mgr) {
> +		devres_free(dr);
> +		return NULL;
>  	}
>  
> -	return mgr;
> +	devres_add(dev, dr);
> +
> +	return dr->mgr;
>  }
>  EXPORT_SYMBOL_GPL(devm_fpga_mgr_create);
>  
> @@ -722,6 +726,59 @@ void fpga_mgr_unregister(struct fpga_manager *mgr)
>  }
>  EXPORT_SYMBOL_GPL(fpga_mgr_unregister);
>  
> +static int fpga_mgr_devres_match(struct device *dev, void *res,
> +				 void *match_data)
> +{
> +	struct fpga_mgr_devres *dr = res;
> +
> +	return match_data == dr->mgr;
> +}
> +
> +static void devm_fpga_mgr_unregister(struct device *dev, void *res)
> +{
> +	struct fpga_mgr_devres *dr = res;
> +
> +	fpga_mgr_unregister(dr->mgr);
> +}
> +
> +/**
> + * devm_fpga_mgr_register - resource managed variant of fpga_mgr_register()
> + * @dev: managing device for this FPGA manager
> + * @mgr: fpga manager struct
> + *
> + * This is the devres variant of fpga_mgr_register() for which the unregister
> + * function will be called automatically when the managing device is detached.
> + */
> +int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr)
> +{
> +	struct fpga_mgr_devres *dr;
> +	int ret;
> +
> +	/*
> +	 * Make sure that the struct fpga_manager * that is passed in is
> +	 * managed itself.
> +	 */
> +	if (WARN_ON(!devres_find(dev, devm_fpga_mgr_release,
> +				 fpga_mgr_devres_match, mgr)))
> +		return -EINVAL;
> +
> +	dr = devres_alloc(devm_fpga_mgr_unregister, sizeof(*dr), GFP_KERNEL);
> +	if (!dr)
> +		return -ENOMEM;
> +
> +	ret = fpga_mgr_register(mgr);
> +	if (ret) {
> +		devres_free(dr);
> +		return ret;
> +	}
> +
> +	dr->mgr = mgr;
> +	devres_add(dev, dr);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(devm_fpga_mgr_register);
> +
>  static void fpga_mgr_dev_release(struct device *dev)
>  {
>  }
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index e8ca62b2cb5b..2bc3030a69e5 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -198,6 +198,8 @@ void fpga_mgr_free(struct fpga_manager *mgr);
>  int fpga_mgr_register(struct fpga_manager *mgr);
>  void fpga_mgr_unregister(struct fpga_manager *mgr);
>  
> +int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr);
> +
>  struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name,
>  					  const struct fpga_manager_ops *mops,
>  					  void *priv);
> -- 
> 2.28.0
> 
Applied series to for-next,

Thanks