Re: [PATCH v5] fpga: region: add owner module and take its refcount

[Marco Pagani]

On 2024-04-19 09:32, Xu Yilun wrote:
> On Mon, Apr 15, 2024 at 07:11:03PM +0200, Marco Pagani wrote:
>> On 2024-04-15 14:19, Marco Pagani wrote:
>>>
>>>
>>> On 2024-04-13 04:35, Xu Yilun wrote:
>>>>>  /**
>>>>> - * fpga_region_register_full - create and register an FPGA Region device
>>>>> + * __fpga_region_register_full - create and register an FPGA Region device
>>>>>   * @parent: device parent
>>>>>   * @info: parameters for FPGA Region
>>>>> + * @owner: owner module containing the get_bridges function
>>>>
>>>> This is too specific and easily get unaligned if we add another
>>>> callback. How about "module containing the region ops"?
>>>
>>> I had some concerns about using the name "region ops" in the kernel-doc
>>> comment since it was not supported by a struct definition nor referenced
>>> in the documentation. However, since the name is now referred to in the
>>> ops_owner pointer, making the change makes sense to me.
>>>
>>
>> On second thought, I think it would be better to leave the @owner
>> description to "module containing the get_bridges function" for the
>> moment. Otherwise, it could confuse the user by blurring the connection
>> between the @owner and @get_bridges parameters.
>>
>> * __fpga_region_register - create and register an FPGA Region device
>> * [...]
>> * @get_bridges: optional function to get bridges to a list
>> * @owner: owner module containing get_bridges function
>>
>> We can always modify the @owner description later, together with all the
>> necessary changes to add a new op, like grouping all ops in a structure
>> and changing the registration function signature.
> 
> OK, it's good to me. I'll apply this patch to for-next.
> 
> Acked-by: Xu Yilun <yilun.xu@xxxxxxxxx>

Thanks, I'll quickly send v6 to fix a minor typo in the kernel-doc:

- @owner: owner module containing get_bridges function
+ @owner: module containing the get_bridges function

Marco

>>>>>   *
>>>>>   * Return: struct fpga_region or ERR_PTR()
>>>>>   */
>>>>>  struct fpga_region *
>>>>> -fpga_region_register_full(struct device *parent, const struct fpga_region_info *info)
>>>>> +__fpga_region_register_full(struct device *parent, const struct fpga_region_info *info,
>>>>> +			    struct module *owner)
>>>>>  {
>>>>>  	struct fpga_region *region;
>>>>>  	int id, ret = 0;
>>>>> @@ -213,6 +215,7 @@ fpga_region_register_full(struct device *parent, const struct fpga_region_info *
>>>>>  	region->compat_id = info->compat_id;
>>>>>  	region->priv = info->priv;
>>>>>  	region->get_bridges = info->get_bridges;
>>>>> +	region->ops_owner = owner;
>>>>>  
>>>>>  	mutex_init(&region->mutex);
>>>>>  	INIT_LIST_HEAD(&region->bridge_list);
>>>>> @@ -241,13 +244,14 @@ fpga_region_register_full(struct device *parent, const struct fpga_region_info *
>>>>>  
>>>>>  	return ERR_PTR(ret);
>>>>>  }
>>>>> -EXPORT_SYMBOL_GPL(fpga_region_register_full);
>>>>> +EXPORT_SYMBOL_GPL(__fpga_region_register_full);
>>>>>  
>>>>>  /**
>>>>> - * fpga_region_register - create and register an FPGA Region device
>>>>> + * __fpga_region_register - create and register an FPGA Region device
>>>>>   * @parent: device parent
>>>>>   * @mgr: manager that programs this region
>>>>>   * @get_bridges: optional function to get bridges to a list
>>>>> + * @owner: owner module containing get_bridges function
>>>>
>>>> ditto
>>>>
>>>>>   *
>>>>>   * This simple version of the register function should be sufficient for most users.
>>>>>   * The fpga_region_register_full() function is available for users that need to
>>>>> @@ -256,17 +260,17 @@ EXPORT_SYMBOL_GPL(fpga_region_register_full);
>>>>>   * Return: struct fpga_region or ERR_PTR()
>>>>>   */
>>>>>  struct fpga_region *
>>>>> -fpga_region_register(struct device *parent, struct fpga_manager *mgr,
>>>>> -		     int (*get_bridges)(struct fpga_region *))
>>>>> +__fpga_region_register(struct device *parent, struct fpga_manager *mgr,
>>>>> +		       int (*get_bridges)(struct fpga_region *), struct module *owner)
>>>>>  {
>>>>>  	struct fpga_region_info info = { 0 };
>>>>>  
>>>>>  	info.mgr = mgr;
>>>>>  	info.get_bridges = get_bridges;
>>>>>  
>>>>> -	return fpga_region_register_full(parent, &info);
>>>>> +	return __fpga_region_register_full(parent, &info, owner);
>>>>>  }
>>>>> -EXPORT_SYMBOL_GPL(fpga_region_register);
>>>>> +EXPORT_SYMBOL_GPL(__fpga_region_register);
>>>>>  
>>>>>  /**
>>>>>   * fpga_region_unregister - unregister an FPGA region
>>>>> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
>>>>> index 9d4d32909340..5fbc05fe70a6 100644
>>>>> --- a/include/linux/fpga/fpga-region.h
>>>>> +++ b/include/linux/fpga/fpga-region.h
>>>>> @@ -36,6 +36,7 @@ struct fpga_region_info {
>>>>>   * @mgr: FPGA manager
>>>>>   * @info: FPGA image info
>>>>>   * @compat_id: FPGA region id for compatibility check.
>>>>> + * @ops_owner: module containing the get_bridges function
>>>>
>>>> ditto
>>>>
>>>> Thanks,
>>>> Yilun
>>>>
>>>>>   * @priv: private data
>>>>>   * @get_bridges: optional function to get bridges to a list
>>>>>   */
>>>>> @@ -46,6 +47,7 @@ struct fpga_region {
>>>>>  	struct fpga_manager *mgr;
>>>>>  	struct fpga_image_info *info;
>>>>>  	struct fpga_compat_id *compat_id;
>>>>> +	struct module *ops_owner;
>>>>>  	void *priv;
>>>>>  	int (*get_bridges)(struct fpga_region *region);
>>>>>  };
>>>>
>>
>