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PM / OPP: Add per OPP table mutex 

Add per OPP table lock to protect opp_table->opp_list.

Note that at few places opp_list is used under the rcu_read_lock() and
so a mutex can't be added there for now. This will be fixed by a later
patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2017-01-23 10:11:41 +05:30 committed by Rafael J. Wysocki
parent b6160e2693
commit 37a73ec0c9
2 changed files with 29 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
drivers/base/power/opp/core.c
View File

@ -854,6 +854,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev)
srcu_init_notifier_head(&opp_table->srcu_head);
INIT_LIST_HEAD(&opp_table->opp_list);
mutex_init(&opp_table->lock);
/* Secure the device table modification */
list_add_rcu(&opp_table->node, &opp_tables);
@ -909,6 +910,7 @@ static void _free_opp_table(struct opp_table *opp_table)
/* dev_list must be empty now */
WARN_ON(!list_empty(&opp_table->dev_list));
mutex_destroy(&opp_table->lock);
list_del_rcu(&opp_table->node);
call_srcu(&opp_table->srcu_head.srcu, &opp_table->rcu_head,
_kfree_device_rcu);
@ -969,6 +971,8 @@ static void _kfree_opp_rcu(struct rcu_head *head)
*/
static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp)
{
mutex_lock(&opp_table->lock);
/*
* Notify the changes in the availability of the operable
* frequency/voltage list.
@ -978,6 +982,8 @@ static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp)
list_del_rcu(&opp->node);
call_srcu(&opp_table->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
mutex_unlock(&opp_table->lock);
_remove_opp_table(opp_table);
}
@ -1007,6 +1013,8 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
if (IS_ERR(opp_table))
goto unlock;
mutex_lock(&opp_table->lock);
list_for_each_entry(opp, &opp_table->opp_list, node) {
if (opp->rate == freq) {
found = true;
@ -1014,6 +1022,8 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
}
}
mutex_unlock(&opp_table->lock);
if (!found) {
dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
__func__, freq);
@ -1083,7 +1093,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
struct opp_table *opp_table)
{
struct dev_pm_opp *opp;
struct list_head *head = &opp_table->opp_list;
struct list_head *head;
int ret;
/*
@ -1094,6 +1104,9 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
* loop, don't replace it with head otherwise it will become an infinite
* loop.
*/
mutex_lock(&opp_table->lock);
head = &opp_table->opp_list;
list_for_each_entry_rcu(opp, &opp_table->opp_list, node) {
if (new_opp->rate > opp->rate) {
head = &opp->node;
@ -1110,12 +1123,17 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
new_opp->supplies[0].u_volt, new_opp->available);
/* Should we compare voltages for all regulators here ? */
return opp->available &&
new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;
ret = opp->available &&
new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;
mutex_unlock(&opp_table->lock);
return ret;
}
new_opp->opp_table = opp_table;
list_add_rcu(&new_opp->node, head);
mutex_unlock(&opp_table->lock);
new_opp->opp_table = opp_table;
ret = opp_debug_create_one(new_opp, opp_table);
if (ret)
@ -1779,6 +1797,8 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
goto unlock;
}
mutex_lock(&opp_table->lock);
/* Do we have the frequency? */
list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
if (tmp_opp->rate == freq) {
@ -1786,6 +1806,9 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
break;
}
}
mutex_unlock(&opp_table->lock);
if (IS_ERR(opp)) {
r = PTR_ERR(opp);
goto unlock;

2
drivers/base/power/opp/opp.h
View File

@ -131,6 +131,7 @@ enum opp_table_access {
* @rcu_head: RCU callback head used for deferred freeing
* @dev_list: list of devices that share these OPPs
* @opp_list: table of opps
* @lock: mutex protecting the opp_list.
* @np: struct device_node pointer for opp's DT node.
* @clock_latency_ns_max: Max clock latency in nanoseconds.
* @shared_opp: OPP is shared between multiple devices.
@ -163,6 +164,7 @@ struct opp_table {
struct rcu_head rcu_head;
struct list_head dev_list;
struct list_head opp_list;
struct mutex lock;
struct device_node *np;
unsigned long clock_latency_ns_max;