Re: [PATCH v3 3/4] fpga: add devm_fpga_region_create

[Moritz Fischer <moritz.fischer.private@gmail.com>]

On Wed, Sep 26, 2018 at 9:12 AM Alan Tull <atull@kernel.org> wrote:
>
> Add devm_fpga_region_create() which is the
> managed version of fpga_region_create().
>
> Change current region drivers to use
> devm_fpga_region_create().
>
> Signed-off-by: Alan Tull <atull@kernel.org>
> Suggested-by: Federico Vaga <federico.vaga@cern.ch>

Acked-by: Moritz Fischer <mdf@kernel.org>
> ---
> v2: add suggested-by
> v3: remove some unclear documentation about fpga_region_unregister
> ---
>  Documentation/driver-api/fpga/fpga-region.rst |  3 ++
>  drivers/fpga/dfl-fme-region.c                 |  6 +--
>  drivers/fpga/dfl.c                            |  6 +--
>  drivers/fpga/fpga-region.c                    | 65 +++++++++++++++++++++++----
>  drivers/fpga/of-fpga-region.c                 |  6 +--
>  include/linux/fpga/fpga-region.h              |  4 ++
>  6 files changed, 70 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/driver-api/fpga/fpga-region.rst b/Documentation/driver-api/fpga/fpga-region.rst
> index f30333c..dc9f75c 100644
> --- a/Documentation/driver-api/fpga/fpga-region.rst
> +++ b/Documentation/driver-api/fpga/fpga-region.rst
> @@ -90,6 +90,9 @@ API to add a new FPGA region
>     :functions: fpga_region
>
>  .. kernel-doc:: drivers/fpga/fpga-region.c
> +   :functions: devm_fpga_region_create
> +
> +.. kernel-doc:: drivers/fpga/fpga-region.c
>     :functions: fpga_region_create
>
>  .. kernel-doc:: drivers/fpga/fpga-region.c
> diff --git a/drivers/fpga/dfl-fme-region.c b/drivers/fpga/dfl-fme-region.c
> index 3fa0de2..1eeb42a 100644
> --- a/drivers/fpga/dfl-fme-region.c
> +++ b/drivers/fpga/dfl-fme-region.c
> @@ -39,7 +39,7 @@ static int fme_region_probe(struct platform_device *pdev)
>         if (IS_ERR(mgr))
>                 return -EPROBE_DEFER;
>
> -       region = fpga_region_create(dev, mgr, fme_region_get_bridges);
> +       region = devm_fpga_region_create(dev, mgr, fme_region_get_bridges);
>         if (!region) {
>                 ret = -ENOMEM;
>                 goto eprobe_mgr_put;
> @@ -51,14 +51,12 @@ static int fme_region_probe(struct platform_device *pdev)
>
>         ret = fpga_region_register(region);
>         if (ret)
> -               goto region_free;
> +               goto eprobe_mgr_put;
>
>         dev_dbg(dev, "DFL FME FPGA Region probed\n");
>
>         return 0;
>
> -region_free:
> -       fpga_region_free(region);
>  eprobe_mgr_put:
>         fpga_mgr_put(mgr);
>         return ret;
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index a9b521b..2c09e50 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -899,7 +899,7 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
>         if (!cdev)
>                 return ERR_PTR(-ENOMEM);
>
> -       cdev->region = fpga_region_create(info->dev, NULL, NULL);
> +       cdev->region = devm_fpga_region_create(info->dev, NULL, NULL);
>         if (!cdev->region) {
>                 ret = -ENOMEM;
>                 goto free_cdev_exit;
> @@ -911,7 +911,7 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
>
>         ret = fpga_region_register(cdev->region);
>         if (ret)
> -               goto free_region_exit;
> +               goto free_cdev_exit;
>
>         /* create and init build info for enumeration */
>         binfo = devm_kzalloc(info->dev, sizeof(*binfo), GFP_KERNEL);
> @@ -942,8 +942,6 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
>
>  unregister_region_exit:
>         fpga_region_unregister(cdev->region);
> -free_region_exit:
> -       fpga_region_free(cdev->region);
>  free_cdev_exit:
>         devm_kfree(info->dev, cdev);
>         return ERR_PTR(ret);
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 0d65220..bde5a9d 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -185,6 +185,10 @@ ATTRIBUTE_GROUPS(fpga_region);
>   * @mgr: manager that programs this region
>   * @get_bridges: optional function to get bridges to a list
>   *
> + * The caller of this function is responsible for freeing the resulting region
> + * struct with fpga_region_free().  Using devm_fpga_region_create() instead is
> + * recommended.
> + *
>   * Return: struct fpga_region or NULL
>   */
>  struct fpga_region
> @@ -230,8 +234,8 @@ struct fpga_region
>  EXPORT_SYMBOL_GPL(fpga_region_create);
>
>  /**
> - * fpga_region_free - free a struct fpga_region
> - * @region: FPGA region created by fpga_region_create
> + * fpga_region_free - free a FPGA region created by fpga_region_create()
> + * @region: FPGA region
>   */
>  void fpga_region_free(struct fpga_region *region)
>  {
> @@ -240,21 +244,69 @@ void fpga_region_free(struct fpga_region *region)
>  }
>  EXPORT_SYMBOL_GPL(fpga_region_free);
>
> +static void devm_fpga_region_release(struct device *dev, void *res)
> +{
> +       struct fpga_region *region = *(struct fpga_region **)res;
> +
> +       fpga_region_free(region);
> +}
> +
> +/**
> + * devm_fpga_region_create - create and initialize a managed FPGA region struct
> + * @dev: device parent
> + * @mgr: manager that programs this region
> + * @get_bridges: optional function to get bridges to a list
> + *
> + * This function is intended for use in a FPGA region driver's probe function.
> + * After the region driver creates the region struct with
> + * devm_fpga_region_create(), it should register it with fpga_region_register().
> + * The region driver's remove function should call fpga_region_unregister().
> + * The region struct allocated with this function will be freed automatically on
> + * driver detach.  This includes the case of a probe function returning error
> + * before calling fpga_region_register(), the struct will still get cleaned up.
> + *
> + * Return: struct fpga_region or NULL
> + */
> +struct fpga_region
> +*devm_fpga_region_create(struct device *dev,
> +                        struct fpga_manager *mgr,
> +                        int (*get_bridges)(struct fpga_region *))
> +{
> +       struct fpga_region **ptr, *region;
> +
> +       ptr = devres_alloc(devm_fpga_region_release, sizeof(*ptr), GFP_KERNEL);
> +       if (!ptr)
> +               return NULL;
> +
> +       region = fpga_region_create(dev, mgr, get_bridges);
> +       if (!region) {
> +               devres_free(ptr);
> +       } else {
> +               *ptr = region;
> +               devres_add(dev, ptr);
> +       }
> +
> +       return region;
> +}
> +EXPORT_SYMBOL_GPL(devm_fpga_region_create);
> +
>  /**
>   * fpga_region_register - register a FPGA region
> - * @region: FPGA region created by fpga_region_create
> + * @region: FPGA region
> + *
>   * Return: 0 or -errno
>   */
>  int fpga_region_register(struct fpga_region *region)
>  {
>         return device_add(&region->dev);
> -
>  }
>  EXPORT_SYMBOL_GPL(fpga_region_register);
>
>  /**
> - * fpga_region_unregister - unregister and free a FPGA region
> + * fpga_region_unregister - unregister a FPGA region
>   * @region: FPGA region
> + *
> + * This function is intended for use in a FPGA region driver's remove function.
>   */
>  void fpga_region_unregister(struct fpga_region *region)
>  {
> @@ -264,9 +316,6 @@ EXPORT_SYMBOL_GPL(fpga_region_unregister);
>
>  static void fpga_region_dev_release(struct device *dev)
>  {
> -       struct fpga_region *region = to_fpga_region(dev);
> -
> -       fpga_region_free(region);
>  }
>
>  /**
> diff --git a/drivers/fpga/of-fpga-region.c b/drivers/fpga/of-fpga-region.c
> index d6a70e4..75f64ab 100644
> --- a/drivers/fpga/of-fpga-region.c
> +++ b/drivers/fpga/of-fpga-region.c
> @@ -410,7 +410,7 @@ static int of_fpga_region_probe(struct platform_device *pdev)
>         if (IS_ERR(mgr))
>                 return -EPROBE_DEFER;
>
> -       region = fpga_region_create(dev, mgr, of_fpga_region_get_bridges);
> +       region = devm_fpga_region_create(dev, mgr, of_fpga_region_get_bridges);
>         if (!region) {
>                 ret = -ENOMEM;
>                 goto eprobe_mgr_put;
> @@ -418,7 +418,7 @@ static int of_fpga_region_probe(struct platform_device *pdev)
>
>         ret = fpga_region_register(region);
>         if (ret)
> -               goto eprobe_free;
> +               goto eprobe_mgr_put;
>
>         of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
>         platform_set_drvdata(pdev, region);
> @@ -427,8 +427,6 @@ static int of_fpga_region_probe(struct platform_device *pdev)
>
>         return 0;
>
> -eprobe_free:
> -       fpga_region_free(region);
>  eprobe_mgr_put:
>         fpga_mgr_put(mgr);
>         return ret;
> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
> index 0521b7f..27cb706 100644
> --- a/include/linux/fpga/fpga-region.h
> +++ b/include/linux/fpga/fpga-region.h
> @@ -44,4 +44,8 @@ void fpga_region_free(struct fpga_region *region);
>  int fpga_region_register(struct fpga_region *region);
>  void fpga_region_unregister(struct fpga_region *region);
>
> +struct fpga_region
> +*devm_fpga_region_create(struct device *dev, struct fpga_manager *mgr,
> +                       int (*get_bridges)(struct fpga_region *));
> +
>  #endif /* _FPGA_REGION_H */
> --
> 2.7.4
>

Thanks,
Moritz