linux-kernel - Re: [PATCH 2/2 v3] drivers: use __free attribute instead of of_node

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Message-ID: <alpine.DEB.2.22.394.2405011355430.3278@hadrien>
Date: Wed, 1 May 2024 13:56:00 +0200 (CEST)
From: Julia Lawall <julia.lawall@...ia.fr>
To: Sudeep Holla <sudeep.holla@....com>
cc: Vincenzo Mezzela <vincenzo.mezzela@...il.com>, gregkh@...uxfoundation.org, 
    javier.carrasco.cruz@...il.com, julia.lawall@...ia.fr, 
    linux-kernel@...r.kernel.org, rafael@...nel.org, skhan@...uxfoundation.org
Subject: Re: [PATCH 2/2 v3] drivers: use __free attribute instead of
 of_node_put()



On Wed, 1 May 2024, Sudeep Holla wrote:

> As mentioned in 1/2, please fix the subject to be more precise.
>
> On Wed, May 01, 2024 at 11:43:13AM +0200, Vincenzo Mezzela wrote:
> > Introduce the __free attribute for scope-based resource management.
> > Resources allocated with __free are automatically released at the end of
> > the scope. This enhancement aims to mitigate memory management issues
> > associated with forgetting to release resources by utilizing __free
> > instead of of_node_put().
> >
> > The declaration of the device_node used within the do-while loops is
> > moved directly within the loop so that the resource is automatically
> > freed at the end of each iteration.
> >
> > Suggested-by: Julia Lawall <julia.lawall@...ia.fr>
> > Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@...il.com>
> > ---
> >  drivers/base/arch_topology.c | 51 +++++++++++++++---------------------
> >  1 file changed, 21 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> > index ea8836f0bb4b..eef26e304018 100644
> > --- a/drivers/base/arch_topology.c
> > +++ b/drivers/base/arch_topology.c
> > @@ -8,6 +8,7 @@
> >
> >  #include <linux/acpi.h>
> >  #include <linux/cacheinfo.h>
> > +#include <linux/cleanup.h>
> >  #include <linux/cpu.h>
> >  #include <linux/cpufreq.h>
> >  #include <linux/device.h>
> > @@ -513,10 +514,10 @@ core_initcall(free_raw_capacity);
> >   */
> >  static int __init get_cpu_for_node(struct device_node *node)
> >  {
> > -	struct device_node *cpu_node;
> >  	int cpu;
> >
> > -	cpu_node = of_parse_phandle(node, "cpu", 0);
> > +	struct device_node *cpu_node __free(device_node) =
> > +		of_parse_phandle(node, "cpu", 0);
>
> Prefer a blank line after this, applies to all the place where you are
> introducing this style.

There should also be no blank line before it.

julia