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PM: QoS: Add check to make sure CPU latency is non-negative 

CPU latency should never be negative, which will be incorrectly high
when converted to unsigned data type.

Commit 8d36694245 ("PM: QoS: Add check to make sure CPU freq is
non-negative") makes sure CPU frequency is non-negative to fix incorrect
behavior in freqency QoS.

Add an analogous check to make sure CPU latency is non-negative so as to
prevent this problem from happening in CPU latency QoS.

Signed-off-by: Clive Lin <clive.lin@mediatek.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Clive Lin 2023-07-31 14:03:54 +08:00 committed by Rafael J. Wysocki
parent 706a741595
commit 5f55836ab4
1 changed files with 7 additions and 2 deletions
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9
kernel/power/qos.c
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@ -220,6 +220,11 @@ static struct pm_qos_constraints cpu_latency_constraints = {
.type = PM_QOS_MIN,
};
static inline bool cpu_latency_qos_value_invalid(s32 value)
{
return value < 0 && value != PM_QOS_DEFAULT_VALUE;
}
/**
* cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit.
*/
@ -263,7 +268,7 @@ static void cpu_latency_qos_apply(struct pm_qos_request *req,
*/
void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value)
{
if (!req)
if (!req || cpu_latency_qos_value_invalid(value))
return;
if (cpu_latency_qos_request_active(req)) {
@ -289,7 +294,7 @@ EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request);
*/
void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value)
{
if (!req)
if (!req || cpu_latency_qos_value_invalid(new_value))
return;
if (!cpu_latency_qos_request_active(req)) {