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

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CPU frequency should never be negative.

If some client driver calls freq_qos_update_request with a
negative value which will be very high in absolute terms,
then frequency QoS sets max CPU freq at fmax as it considers
it's absolute value but it will add plist node with negative
priority.

plist node has priority from INT_MIN (highest) to INT_MAX(lowest).
Once priority is set as negative, another client will not be able
to reduce CPU frequency.

Adding check to make sure CPU freq is non-negative will fix
this problem.

Signed-off-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Shivnandan Kumar 2022-07-15 17:55:39 +05:30 committed by Rafael J. Wysocki
parent e0dccc3b76
commit 8d36694245
1 changed files with 2 additions and 2 deletions
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4
kernel/power/qos.c
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@ -531,7 +531,7 @@ int freq_qos_add_request(struct freq_constraints *qos,
{
int ret;
if (IS_ERR_OR_NULL(qos) || !req)
if (IS_ERR_OR_NULL(qos) || !req || value < 0)
return -EINVAL;
if (WARN(freq_qos_request_active(req),
@ -563,7 +563,7 @@ EXPORT_SYMBOL_GPL(freq_qos_add_request);
*/
int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
{
if (!req)
if (!req || new_value < 0)
return -EINVAL;
if (WARN(!freq_qos_request_active(req),