linux-kernel - Re: [PATCH 2/7] thermal: of: Use scoped device node handling to simplify thermal_of_trips

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <c8f2e2b74bc46cf6870909add3f1ccd6@manjaro.org>
Date: Sat, 17 Aug 2024 04:47:25 +0200
From: Dragan Simic <dsimic@...jaro.org>
To: Chen-Yu Tsai <wenst@...omium.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, "Rafael J.
 Wysocki" <rafael@...nel.org>, Daniel Lezcano <daniel.lezcano@...aro.org>,
 Zhang Rui <rui.zhang@...el.com>, Lukasz Luba <lukasz.luba@....com>, Amit
 Kucheria <amitk@...nel.org>, Thara Gopinath <thara.gopinath@...il.com>,
 Thierry Reding <thierry.reding@...il.com>, Jonathan Hunter
 <jonathanh@...dia.com>, Vasily Khoruzhick <anarsoul@...il.com>, Yangtao Li
 <tiny.windzz@...il.com>, Chen-Yu Tsai <wens@...e.org>, Jernej Skrabec
 <jernej.skrabec@...il.com>, Samuel Holland <samuel@...lland.org>,
 linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, linux-tegra@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev
Subject: Re: [PATCH 2/7] thermal: of: Use scoped device node handling to
 simplify thermal_of_trips_init()

On 2024-08-15 09:15, Chen-Yu Tsai wrote:
> On Wed, Aug 14, 2024 at 10:17:48PM +0200, Krzysztof Kozlowski wrote:
>> Obtain the device node reference with scoped/cleanup.h to reduce error
>> handling and make the code a bit simpler.
>> 
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> ---
>>  drivers/thermal/thermal_of.c | 14 ++++----------
>>  1 file changed, 4 insertions(+), 10 deletions(-)
>> 
>> diff --git a/drivers/thermal/thermal_of.c 
>> b/drivers/thermal/thermal_of.c
>> index a2278d4ad886..c8ded4462bb8 100644
>> --- a/drivers/thermal/thermal_of.c
>> +++ b/drivers/thermal/thermal_of.c
>> @@ -117,10 +117,9 @@ static int thermal_of_populate_trip(struct 
>> device_node *np,
>>  static struct thermal_trip *thermal_of_trips_init(struct device_node 
>> *np, int *ntrips)
>>  {
>>  	struct thermal_trip *tt;
>> -	struct device_node *trips;
>>  	int ret, count;
>> 
>> -	trips = of_get_child_by_name(np, "trips");
>> +	struct device_node *trips __free(device_node) = 
>> of_get_child_by_name(np, "trips");
>>  	if (!trips) {
>>  		pr_err("Failed to find 'trips' node\n");
>>  		return ERR_PTR(-EINVAL);
>> @@ -129,15 +128,12 @@ static struct thermal_trip 
>> *thermal_of_trips_init(struct device_node *np, int *n
>>  	count = of_get_child_count(trips);
>>  	if (!count) {
>>  		pr_err("No trip point defined\n");
>> -		ret = -EINVAL;
>> -		goto out_of_node_put;
>> +		return ERR_PTR(-EINVAL);
>>  	}
>> 
>>  	tt = kzalloc(sizeof(*tt) * count, GFP_KERNEL);
>> -	if (!tt) {
>> -		ret = -ENOMEM;
>> -		goto out_of_node_put;
>> -	}
>> +	if (!tt)
>> +		return ERR_PTR(-ENOMEM);
>> 
>>  	*ntrips = count;
> 
> Also drop the "of_node_put(trips);" in the successful path?
> 
> Once fixed,
> 
> Reviewed-by: Chen-Yu Tsai <wenst@...omium.org>
> 
> And I plan to send a patch on top of this making "tt" auto released,
> thereby eliminating the error path.

Ah, with that additional patch in place, I totally agree with
moving "*ntrips = 0" to the top.

>> @@ -155,8 +151,6 @@ static struct thermal_trip 
>> *thermal_of_trips_init(struct device_node *np, int *n
>>  out_kfree:
>>  	kfree(tt);
>>  	*ntrips = 0;
>> -out_of_node_put:
>> -	of_node_put(trips);
>> 
>>  	return ERR_PTR(ret);
>>  }
>> 
>> --
>> 2.43.0
>>