linux-kernel - Re: [PATCH 15/22] Input: iqs7222 - use cleanup facility for fwnodes

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Message-ID: <1b2254fa-9f1a-4150-b610-abfb55e4d161@gmail.com>
Date: Wed, 4 Sep 2024 20:46:00 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: linux-input@...r.kernel.org,
 Michael Hennerich <michael.hennerich@...log.com>,
 Ville Syrjala <syrjala@....fi>,
 Support Opensource <support.opensource@...semi.com>,
 Eddie James <eajames@...ux.ibm.com>, Andrey Moiseev <o2g.org.ru@...il.com>,
 Hans de Goede <hdegoede@...hat.com>, Jeff LaBundy <jeff@...undy.com>,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 15/22] Input: iqs7222 - use cleanup facility for fwnodes

On 04/09/2024 20:26, Dmitry Torokhov wrote:
> On Wed, Sep 04, 2024 at 12:50:44PM +0200, Javier Carrasco wrote:
>> Hi Dmitry,
>>
>> On 04/09/2024 06:48, Dmitry Torokhov wrote:
>>> Use __free(fwnode_handle) cleanup facility to ensure that references to
>>> acquired fwnodes are dropped at appropriate times automatically.
>>>
>>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
>>> ---
>>>  drivers/input/misc/iqs7222.c | 30 ++++++++++++++----------------
>>>  1 file changed, 14 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
>>> index 9ca5a743f19f..d9b87606ff7a 100644
>>> --- a/drivers/input/misc/iqs7222.c
>>> +++ b/drivers/input/misc/iqs7222.c
>>
>> ...
>>
>>> @@ -2818,9 +2813,9 @@ static int iqs7222_parse_reg_grp(struct iqs7222_private *iqs7222,
>>>  				 int reg_grp_index)
>>>  {
>>>  	struct i2c_client *client = iqs7222->client;
>>> -	struct fwnode_handle *reg_grp_node;
>>>  	int error;
>>>  
>>
>> Nit: reg_grp_node could stay at the top (where it used to be), as you
>> are assigning it to NULL because there are no sensible assignments at
>> this point.
>>
>>> +	struct fwnode_handle *reg_grp_node __free(fwnode_handle) = NULL;
>>>  	if (iqs7222_reg_grp_names[reg_grp]) {
>>>  		char reg_grp_name[16];
> 
> I think this follows Linus' guidance (in spirit) to combine declaration
> and initialization for objects using __cleanup(). If it was Rust I'd
> written it as
> 
> 	let reg_grp_node = if let Some(...) { ... } else { ... };
> 
> so declaration and initialization would be the same, but with C this is
> the closest I could come up with.
> 
> Thanks.
> 

Combining the declaration and initialization was right, no doubt about
that. I was just nitpicking that the variable declaration could have
been done at the top, as it used to be. The same as you did, but not
separating the declaration from the rest as there are no instructions in
between.

My second thought was that you might be attempting to declare the
variable as near as possible to the "some" initialization, so you moved
it a little bit to get it closer :)

Either way, if you did that on purpose, then

Reviewed-by: Javier Carrasco <javier.carrasco.cruz@...il.com>