在 2025/8/27 17:17, Sudeep Holla 写道:
On Wed, Aug 27, 2025 at 09:30:13AM +0100, Ben Horgan wrote:
Hi Zihuan,
On 8/27/25 03:31, Zihuan Zhang wrote:
Replace the manual cpufreq_cpu_put() with __free(put_cpufreq_policy)
annotation for policy references. This reduces the risk of reference
counting mistakes and aligns the code with the latest kernel style.
No functional change intended.
Signed-off-by: Zihuan Zhang <zhangzihuan@xxxxxxxxxx>
---
arch/arm64/kernel/topology.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 5d07ee85bdae..e3cb6d54f35b 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -307,17 +307,16 @@ int arch_freq_get_on_cpu(int cpu)
*/
if (!housekeeping_cpu(cpu, HK_TYPE_TICK) ||
time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) {
- struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+ struct cpufreq_policy *policy __free(put_cpufreq_policy);
Based on the guidance, in include/linux/cleanup.h, I would expect the
assignment to be done on this line.
"...the recommendation is to always define and assign variables in one
* statement and not group variable definitions at the top of the
* function when __free() is used."
Agreed. I did something similar recently and there was a code path where
variable wasn't initialised and ended up with freeing unassigned pointer.
So it is more than just a recommendation sometimes.
Thanks a lot for your suggestions.
We are also considering introducing a WITH_CPUFREQ_POLICY wrapper to
encapsulate the cpufreq_cpu_get/put usage, so that the release order
won’t be accidentally changed.
Link:
https://lore.kernel.org/all/874d821e-8ea3-40ac-921b-c19bb380a456@xxxxxxxxxx/
Do you have any suggestions or preferences on this direction?
