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Subject: Re: [PATCH 01/10] fpga: fpga-mgr: Add devm_fpga_mgr_register() API
To:     Moritz Fischer <mdf@kernel.org>, linux-fpga@vger.kernel.org
Cc:     hao.wu@intel.com, michal.simek@xilinx.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        russell.h.weight@intel.com, matthew.gerlach@intel.com
References: <20201004051423.75879-1-mdf@kernel.org>
 <20201004051423.75879-2-mdf@kernel.org>
From:   Tom Rix <trix@redhat.com>
Message-ID: <b00ad633-8703-8d1f-d5fe-c4483cd19b79@redhat.com>
Date:   Sun, 4 Oct 2020 11:08:11 -0700
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On 10/3/20 10:14 PM, 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().
>
> Signed-off-by: Moritz Fischer <mdf@kernel.org>
> ---
>  drivers/fpga/fpga-mgr.c       | 76 ++++++++++++++++++++++++++++++-----
>  include/linux/fpga/fpga-mgr.h |  2 +
>  2 files changed, 68 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> index f38bab01432e..774ac98fb69c 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
> @@ -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 +726,58 @@ void fpga_mgr_unregister(struct fpga_manager *mgr)
>  }
>  EXPORT_SYMBOL_GPL(fpga_mgr_unregister);
>  
> +static int fpga_mgr_devres_match(struct device *dev, void *priv,
> +				 void *match_data)
> +{
> +	struct fpga_mgr_devres *dr = priv;
> +
> +	return match_data == dr->mgr;
> +}
> +
> +static void devm_fpga_mgr_unregister(struct device *dev, void *priv)
> +{
> +	struct fpga_mgr_devres *dr = priv;
> +
> +	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 err;

nit

int ret;

Fine if it isn't changed.

Reviewed-by: Tom Rix <trix@redhat.com>

> +
> +	/* 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;
> +
> +	err = fpga_mgr_register(mgr);
> +	if (err) {
> +		devres_free(dr);
> +		return err;
> +	}
> +
> +	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);