Re: [PATCH] thermal: cpu_cooling: Remove usage of devm functions

From: Viresh Kumar
Date: Wed Aug 19 2015 - 04:24:24 EST


On Wed, Aug 19, 2015 at 11:52 AM, Vaishali Thakkar
<vthakkar1994@xxxxxxxxx> wrote:
> In the function cpufreq_get_requested_power, the memory allocated
> for load_cpu is live within the function only. And after the
> allocation it is immediately freed with devm_kfree. There is no
> need to allocate memory for load_cpu with devm function so replace
> devm_kcalloc with kcalloc and devm_kfree with kfree.
>
> Signed-off-by: Vaishali Thakkar <vthakkar1994@xxxxxxxxx>
> ---
> This patch is having one checkpatch.pl warning which suggests that
> kfree(NULL) is safe. But I think leaving code with if is nice
> because it reflects the fact that kcalloc was under an if. So, I
> have ignored checkpatch. If maintainer wants me to go for changing
> things, I am fine with it too.

I will rather ask you to do this:

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 620dcd405ff6..a04055ea5d94 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -584,8 +584,8 @@ static int cpufreq_get_requested_power(struct
thermal_cooling_device *cdev,
if (trace_thermal_power_cpu_get_power_enabled()) {
u32 ncpus = cpumask_weight(&cpufreq_device->allowed_cpus);

- load_cpu = devm_kcalloc(&cdev->device, ncpus, sizeof(*load_cpu),
- GFP_KERNEL);
+ load_cpu = kcalloc(&cdev->device, ncpus, sizeof(*load_cpu),
+ GFP_KERNEL);
}

for_each_cpu(cpu, &cpufreq_device->allowed_cpus) {
@@ -607,22 +607,20 @@ static int cpufreq_get_requested_power(struct
thermal_cooling_device *cdev,

dynamic_power = get_dynamic_power(cpufreq_device, freq);
ret = get_static_power(cpufreq_device, tz, freq, &static_power);
- if (ret) {
- if (load_cpu)
- devm_kfree(&cdev->device, load_cpu);
- return ret;
- }
+ if (ret)
+ goto free;

- if (load_cpu) {
+ if (load_cpu)
trace_thermal_power_cpu_get_power(
&cpufreq_device->allowed_cpus,
freq, load_cpu, i, dynamic_power, static_power);

- devm_kfree(&cdev->device, load_cpu);
- }
-
*power = static_power + dynamic_power;
- return 0;
+
+free:
+ kfree(&cdev->device, load_cpu);
+
+ return ret;
}
--
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