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Subject[PATCH] PM: QoS: Add check to make sure CPU latency is non-negative
Date
CPU latency should never be negative, which will be incorrectly high
when converted to unsigned data type. Commit 8d36694245f2 ("PM: QoS:
Add check to make sure CPU freq is non-negative") makes sure CPU freq
is non-negative to fix incorrect behavior in freq_qos. Adding a check
to make sure CPU latency is non-negative can prevent this problem
from happening in cpu_latency_qos.

Signed-off-by: Clive Lin <clive.lin@mediatek.com>
---
kernel/power/qos.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 782d3b41c1f3..4244b069442e 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -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)) {
--
2.18.0
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