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 --- drivers/base/power/opp/core.c | 31 +++++++++++++++++++++++++++---- drivers/base/power/opp/opp.h | 2 ++ 2 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index 622dd32f8dda..dcebd5efb6a1 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -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; diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h index 0a5eb4d1e8f7..105243b06373 100644 --- a/drivers/base/power/opp/opp.h +++ b/drivers/base/power/opp/opp.h @@ -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;