opp: Replace list_kref with a local counter

A kref or refcount isn't the right tool to be used here for counting
number of devices that are sharing the static OPPs created for the OPP
table. For example, we are reinitializing the kref again, after it
reaches a value of 0 and frees the resources, if the static OPPs get
added for the same OPP table structure (as the OPP table structure was
never freed). That is messy and very unclear.

This patch makes parsed_static_opps an unsigned integer and uses it to
count the number of users of the static OPPs. The increment and
decrement to parsed_static_opps is done under opp_table->lock now to
make sure no races are possible if the OPP table is getting added and
removed in parallel (which doesn't happen in practice, but can in
theory).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 01a500e2c40a..d14e27102730 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -127,11 +127,10 @@ enum opp_table_access {
  * @dev_list:	list of devices that share these OPPs
  * @opp_list:	table of opps
  * @kref:	for reference count of the table.
- * @list_kref:	for reference count of the OPP list.
  * @lock:	mutex protecting the opp_list and dev_list.
  * @np:		struct device_node pointer for opp's DT node.
  * @clock_latency_ns_max: Max clock latency in nanoseconds.
- * @parsed_static_opps: True if OPPs are initialized from DT.
+ * @parsed_static_opps: Count of devices for which OPPs are initialized from DT.
  * @shared_opp: OPP is shared between multiple devices.
  * @suspend_opp: Pointer to OPP to be used during device suspend.
  * @genpd_virt_dev_lock: Mutex protecting the genpd virtual device pointers.
@@ -167,7 +166,6 @@ struct opp_table {
 	struct list_head dev_list;
 	struct list_head opp_list;
 	struct kref kref;
-	struct kref list_kref;
 	struct mutex lock;
 
 	struct device_node *np;
@@ -176,7 +174,7 @@ struct opp_table {
 	/* For backward compatibility with v1 bindings */
 	unsigned int voltage_tolerance_v1;
 
-	bool parsed_static_opps;
+	unsigned int parsed_static_opps;
 	enum opp_table_access shared_opp;
 	struct dev_pm_opp *suspend_opp;