linux-kernel - Re: [PATCH net-next] net: dsa: mv88e6xxx: fix unreleased fwnode_handle in setup

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Message-ID: <f148a61d-4ad5-4f62-b1f0-d216e1873067@gmail.com>
Date: Sun, 20 Oct 2024 00:21:07 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: Florian Fainelli <f.fainelli@...il.com>,
 Vladimir Oltean <olteanv@...il.com>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Linus Walleij <linus.walleij@...aro.org>, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: fix unreleased
 fwnode_handle in setup_port()

On 19/10/2024 23:59, Andrew Lunn wrote:
> On Sat, Oct 19, 2024 at 10:16:49PM +0200, Javier Carrasco wrote:
>> 'ports_fwnode' is initialized via device_get_named_child_node(), which
>> requires a call to fwnode_handle_put() when the variable is no longer
>> required to avoid leaking memory.
>>
>> Add the missing fwnode_handle_put() after 'ports_fwnode' has been used
>> and is no longer required.
> 
> As you point out, the handle is obtained with
> device_get_named_child_node(). It seems odd to use a fwnode_ function
> not a device_ function to release the handle. Is there a device_
> function?
> 
> 	Andrew

Hi Andrew,

device_get_named_child_node() receives a pointer to a *device*, and
returns a child node (a pointer to an *fwnode_handle*). That is what has
to be released, and therefore fwnode_handle_put() is the right one.

Note that device_get_named_child_node() documents how to release the
fwnode pointer:

"The caller is responsible for calling fwnode_handle_put() on the
returned fwnode pointer."

Best regards,
Javier Carrasco