Re: [PATCH v2 linux-next] media: i2c: st-mipid02: replace of_node_put() with __free

[Benjamin Mugnier <benjamin.mugnier@foss.st.com>]

Hi,

On 5/14/24 17:20, R Sundar wrote:
> Hi,
> 
> Thanks for the comments.
> 
> On 13/05/24 17:13, Benjamin Mugnier wrote:
>> Hi,
>>
>> I took sometime to reflect on this. Currently I favor drivers
>> consistency.
> 
> 
>> Merging this patch as is would introduce some differences between the
>> vgxy61 and other drivers that follow the 'of_node_put' flow, which I
>> think is not an improvement.
>>
> 
> I checked st-vgxy61.c file, I didn't find of_node_put().

Apologize, I meant st-mipid02.

> Any file apart from this,  you want to see those changes? If yes let me
> know, please.
> Meanwhile I am also looking into it.
> 
> This patch mainly reduce the goto error statements and increases
> readability of the code.
> 
>> Now, this patch is certainly good. Would it be possible to extend it to
>> all other drivers using the 'of_node_put' ?
>>
> yes, people are working on it to replace of_node_put() in many places.
> soon many patches can be expected to come in , for replacing of_node_put
> with auto cleanup module.
> I am also adding these changes to few other files also.

Good, I'd rather see a series with all these files then to ease the
review. But I only maintain the st-mipid02 so other people opinion may
differ.

> 
> Thanks,
> >> That would the consistency issue while improving code quality at the
>> same time.
>>
>> Thank you.
>>  >
>> On 4/29/24 18:37, R Sundar wrote:
>>> Use the new cleanup magic to replace of_node_put() with
>>> __free(device_node) marking to auto release and to simplify the error
>>> paths.
>>>
>>> Suggested-by: Julia Lawall <julia.lawall@inria.fr>
>>> Signed-off-by: R Sundar <prosunofficial@gmail.com>
>>> ---
>>>
>>> Changes since v1 -
>>>
>>> - Added missed out __free() marking in mipid02_parse_tx_ep().
>>> - In mipid02_parse_tx_ep(), In error case, return value is always
>>> -EINVAL.  so
>>> sending the -EINVAL instead of ret variable value.
>>>
>>> Link to v1 -
>>> https://lore.kernel.org/all/20240427095643.11486-1-prosunofficial@gmail.com/#t
>>>
>>>   drivers/media/i2c/st-mipid02.c | 37 +++++++++-------------------------
>>>   1 file changed, 9 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/drivers/media/i2c/st-mipid02.c
>>> b/drivers/media/i2c/st-mipid02.c
>>> index f250640729ca..bd3cf94f8534 100644
>>> --- a/drivers/media/i2c/st-mipid02.c
>>> +++ b/drivers/media/i2c/st-mipid02.c
>>> @@ -715,31 +715,28 @@ static int mipid02_parse_rx_ep(struct
>>> mipid02_dev *bridge)
>>>       struct v4l2_fwnode_endpoint ep = { .bus_type =
>>> V4L2_MBUS_CSI2_DPHY };
>>>       struct i2c_client *client = bridge->i2c_client;
>>>       struct v4l2_async_connection *asd;
>>> -    struct device_node *ep_node;
>>>       int ret;
>>>         /* parse rx (endpoint 0) */
>>> -    ep_node =
>>> of_graph_get_endpoint_by_regs(bridge->i2c_client->dev.of_node,
>>> -                        0, 0);
>>> +    struct device_node *ep_node __free(device_node) =
>>> +       
>>> of_graph_get_endpoint_by_regs(bridge->i2c_client->dev.of_node, 0, 0);
>>>       if (!ep_node) {
>>>           dev_err(&client->dev, "unable to find port0 ep");
>>> -        ret = -EINVAL;
>>> -        goto error;
>>> +        return -EINVAL;
>>>       }
>>>         ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep_node),
>>> &ep);
>>>       if (ret) {
>>>           dev_err(&client->dev, "Could not parse v4l2 endpoint %d\n",
>>>               ret);
>>> -        goto error_of_node_put;
>>> +        return ret;
>>>       }
>>>         /* do some sanity checks */
>>>       if (ep.bus.mipi_csi2.num_data_lanes > 2) {
>>>           dev_err(&client->dev, "max supported data lanes is 2 / got
>>> %d",
>>>               ep.bus.mipi_csi2.num_data_lanes);
>>> -        ret = -EINVAL;
>>> -        goto error_of_node_put;
>>> +        return -EINVAL;
>>>       }
>>>         /* register it for later use */
>>> @@ -750,7 +747,6 @@ static int mipid02_parse_rx_ep(struct mipid02_dev
>>> *bridge)
>>>       asd = v4l2_async_nf_add_fwnode_remote(&bridge->notifier,
>>>                             of_fwnode_handle(ep_node),
>>>                             struct v4l2_async_connection);
>>> -    of_node_put(ep_node);
>>>         if (IS_ERR(asd)) {
>>>           dev_err(&client->dev, "fail to register asd to notifier %ld",
>>> @@ -764,46 +760,31 @@ static int mipid02_parse_rx_ep(struct
>>> mipid02_dev *bridge)
>>>           v4l2_async_nf_cleanup(&bridge->notifier);
>>>         return ret;
>>> -
>>> -error_of_node_put:
>>> -    of_node_put(ep_node);
>>> -error:
>>> -
>>> -    return ret;
>>>   }
>>>     static int mipid02_parse_tx_ep(struct mipid02_dev *bridge)
>>>   {
>>>       struct v4l2_fwnode_endpoint ep = { .bus_type =
>>> V4L2_MBUS_PARALLEL };
>>>       struct i2c_client *client = bridge->i2c_client;
>>> -    struct device_node *ep_node;
>>>       int ret;
>>>         /* parse tx (endpoint 2) */
>>> -    ep_node =
>>> of_graph_get_endpoint_by_regs(bridge->i2c_client->dev.of_node,
>>> -                        2, 0);
>>> +    struct device_node *ep_node __free(device_node) =
>>> +       
>>> of_graph_get_endpoint_by_regs(bridge->i2c_client->dev.of_node, 2, 0);
>>>       if (!ep_node) {
>>>           dev_err(&client->dev, "unable to find port1 ep");
>>> -        ret = -EINVAL;
>>> -        goto error;
>>> +        return -EINVAL;
>>>       }
>>>         ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep_node),
>>> &ep);
>>>       if (ret) {
>>>           dev_err(&client->dev, "Could not parse v4l2 endpoint\n");
>>> -        goto error_of_node_put;
>>> +        return -EINVAL;
>>>       }
>>>   -    of_node_put(ep_node);
>>>       bridge->tx = ep;
>>>         return 0;
>>> -
>>> -error_of_node_put:
>>> -    of_node_put(ep_node);
>>> -error:
>>> -
>>> -    return -EINVAL;
>>>   }
>>>     static int mipid02_probe(struct i2c_client *client)
>>
> 

-- 
Regards,

Benjamin