[PATCH 1/2] efi_loader: function to unlink udevice and handle

[Ilias Apalodimas]

Hi Heinrich, 

On Mon, Oct 03, 2022 at 11:44:58AM +0200, Heinrich Schuchardt wrote:
> When deleting a device or a handle we must remove the link between the two
> to avoid dangling references.
> 
> Provide function efi_unlink_dev() for this purpose.
> 
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  include/efi_loader.h        |  1 +
>  lib/efi_loader/efi_helper.c | 19 +++++++++++++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index ad01395b39..5a993b0d2e 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -708,6 +708,7 @@ const char *guid_to_sha_str(const efi_guid_t *guid);
>  int algo_to_len(const char *algo);
>  
>  int efi_link_dev(efi_handle_t handle, struct udevice *dev);
> +int efi_unlink_dev(efi_handle_t handle);
>  
>  /**
>   * efi_size_in_pages() - convert size in bytes to size in pages
> diff --git a/lib/efi_loader/efi_helper.c b/lib/efi_loader/efi_helper.c
> index 8ed564e261..c71e87d118 100644
> --- a/lib/efi_loader/efi_helper.c
> +++ b/lib/efi_loader/efi_helper.c
> @@ -171,3 +171,22 @@ int efi_link_dev(efi_handle_t handle, struct udevice *dev)
>  	handle->dev = dev;
>  	return dev_tag_set_ptr(dev, DM_TAG_EFI, handle);
>  }
> +
> +/**
> + * efi_unlink_dev() - unlink udevice and handle
> + *
> + * @handle:	EFI handle to unlink
> + *
> + * Return:	0 on success, negative on failure
> + */
> +int efi_unlink_dev(efi_handle_t handle)
> +{
> +	int ret;
> +
> +	ret = dev_tag_del(handle->dev, DM_TAG_EFI);
> +	if (ret)
> +		return ret;

Is handle->dev always guaranteed to hold a valid ptr?
Would it make sense to add an if here and use this function everywhere
instead of sprinkling dev_tag_del() around?

> +	handle->dev = NULL;
> +
> +	return 0;
> +}
> -- 
> 2.37.2
> 

Thanks
/Ilias