PM: PM QOS update fix

This update handles a use case where pm_qos update requests need to
silently fail if the update is being sent to a handle that is NULL.

The problem was that the original pm_qos silently fails when a request
update is passed to a parameter that has not been added to the list yet.
This update restores that behavior.

Signed-off-by: markgross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 14 insertions, 12 deletions

diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index a1aea040eb5..f42d3f737a3 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -252,19 +252,21 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
         int pending_update = 0;
         s32 temp;
 
-        spin_lock_irqsave(&pm_qos_lock, flags);
-        if (new_value == PM_QOS_DEFAULT_VALUE)
-                temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
-        else
-                temp = new_value;
-
-        if (temp != pm_qos_req->value) {
-                pending_update = 1;
-                pm_qos_req->value = temp;
+        if (pm_qos_req) { /*guard against callers passing in null */
+                spin_lock_irqsave(&pm_qos_lock, flags);
+                if (new_value == PM_QOS_DEFAULT_VALUE)
+                        temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
+                else
+                        temp = new_value;
+
+                if (temp != pm_qos_req->value) {
+                        pending_update = 1;
+                        pm_qos_req->value = temp;
+                }
+                spin_unlock_irqrestore(&pm_qos_lock, flags);
+                if (pending_update)
+                        update_target(pm_qos_req->pm_qos_class);
         }
-        spin_unlock_irqrestore(&pm_qos_lock, flags);
-        if (pending_update)
-                update_target(pm_qos_req->pm_qos_class);
 }
 EXPORT_SYMBOL_GPL(pm_qos_update_request);