2024-02-13 22:41:17

by Daniel Lezcano

Subject: [PATCH] powercap: dtpm_cpu: Fix error check against freq_qos_add_request()

The caller of the function freq_qos_add_request() checks again a non
zero value but freq_qos_add_request() can return '1' if the request
already exists. Therefore, the setup function fails while the QoS
request actually did not failed.

Fix that by changing the check against a negative value like all the
other callers of the function.

Fixes: 0e8f68d7f0485 ("Add CPU energy model based support")
Signed-off-by: Daniel Lezcano <[email protected]>
---
drivers/powercap/dtpm_cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
index 9193c3b8edeb..ae7ee611978b 100644
--- a/drivers/powercap/dtpm_cpu.c
+++ b/drivers/powercap/dtpm_cpu.c
@@ -219,7 +219,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
ret = freq_qos_add_request(&policy->constraints,
&dtpm_cpu->qos_req, FREQ_QOS_MAX,
pd->table[pd->nr_perf_states - 1].frequency);
- if (ret)
+ if (ret < 0)
goto out_dtpm_unregister;

cpufreq_cpu_put(policy);
--
2.34.1

2024-02-16 19:07:19

by Rafael J. Wysocki

Subject: Re: [PATCH] powercap: dtpm_cpu: Fix error check against freq_qos_add_request()

On Tue, Feb 13, 2024 at 11:39 PM Daniel Lezcano
<[email protected]> wrote:
>
> The caller of the function freq_qos_add_request() checks again a non
> zero value but freq_qos_add_request() can return '1' if the request
> already exists. Therefore, the setup function fails while the QoS
> request actually did not failed.
>
> Fix that by changing the check against a negative value like all the
> other callers of the function.
>
> Fixes: 0e8f68d7f0485 ("Add CPU energy model based support")
> Signed-off-by: Daniel Lezcano <[email protected]>
> ---
> drivers/powercap/dtpm_cpu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
> index 9193c3b8edeb..ae7ee611978b 100644
> --- a/drivers/powercap/dtpm_cpu.c
> +++ b/drivers/powercap/dtpm_cpu.c
> @@ -219,7 +219,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
> ret = freq_qos_add_request(&policy->constraints,
> &dtpm_cpu->qos_req, FREQ_QOS_MAX,
> pd->table[pd->nr_perf_states - 1].frequency);
> - if (ret)
> + if (ret < 0)
> goto out_dtpm_unregister;
>
> cpufreq_cpu_put(policy);
> --

Applied as 6.9 material, thanks!