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

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Message-ID: <ZtimWmQ2B_WlcvTw@google.com>
Date: Wed, 4 Sep 2024 11:26:34 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Javier Carrasco <javier.carrasco.cruz@...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 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.

-- 
Dmitry