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authorViresh Kumar <viresh.kumar@linaro.org>2017-01-23 10:11:48 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-01-30 09:22:22 +0100
commit5b650b388844f26c61c70564865598836d05dcb3 (patch)
tree93ae6faaad201381793f8322b6d9c227e2c489b0
parent8a31d9d94297b1ecae3012069d35d78c959693c2 (diff)
PM / OPP: Take kref from _find_opp_table()
Take reference of the OPP table from within _find_opp_table(). Also update the callers of _find_opp_table() to call dev_pm_opp_put_opp_table() after they have used the OPP table. Note that _find_opp_table() increments the reference under the opp_table_lock. Now that the OPP table wouldn't get freed until the callers of _find_opp_table() call dev_pm_opp_put_opp_table(), there is no need to take the opp_table_lock or rcu_read_lock() around it. Drop them. 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>
-rw-r--r--drivers/base/power/opp/core.c191
-rw-r--r--drivers/base/power/opp/cpu.c26
2 files changed, 95 insertions, 122 deletions
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index a6efa818029a..69452a4bcda7 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -54,6 +54,21 @@ static struct opp_device *_find_opp_dev(const struct device *dev,
return NULL;
}
+struct opp_table *_find_opp_table_unlocked(struct device *dev)
+{
+ struct opp_table *opp_table;
+
+ list_for_each_entry(opp_table, &opp_tables, node) {
+ if (_find_opp_dev(dev, opp_table)) {
+ _get_opp_table_kref(opp_table);
+
+ return opp_table;
+ }
+ }
+
+ return ERR_PTR(-ENODEV);
+}
+
/**
* _find_opp_table() - find opp_table struct using device pointer
* @dev: device pointer used to lookup OPP table
@@ -64,28 +79,22 @@ static struct opp_device *_find_opp_dev(const struct device *dev,
* Return: pointer to 'struct opp_table' if found, otherwise -ENODEV or
* -EINVAL based on type of error.
*
- * Locking: For readers, this function must be called under rcu_read_lock().
- * opp_table is a RCU protected pointer, which means that opp_table is valid
- * as long as we are under RCU lock.
- *
- * For Writers, this function must be called with opp_table_lock held.
+ * The callers must call dev_pm_opp_put_opp_table() after the table is used.
*/
struct opp_table *_find_opp_table(struct device *dev)
{
struct opp_table *opp_table;
- opp_rcu_lockdep_assert();
-
if (IS_ERR_OR_NULL(dev)) {
pr_err("%s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
- list_for_each_entry_rcu(opp_table, &opp_tables, node)
- if (_find_opp_dev(dev, opp_table))
- return opp_table;
+ mutex_lock(&opp_table_lock);
+ opp_table = _find_opp_table_unlocked(dev);
+ mutex_unlock(&opp_table_lock);
- return ERR_PTR(-ENODEV);
+ return opp_table;
}
/**
@@ -175,23 +184,20 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
* @dev: device for which we do this operation
*
* Return: This function returns the max clock latency in nanoseconds.
- *
- * Locking: This function takes rcu_read_lock().
*/
unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
{
struct opp_table *opp_table;
unsigned long clock_latency_ns;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table))
- clock_latency_ns = 0;
- else
- clock_latency_ns = opp_table->clock_latency_ns_max;
+ return 0;
+
+ clock_latency_ns = opp_table->clock_latency_ns_max;
+
+ dev_pm_opp_put_opp_table(opp_table);
- rcu_read_unlock();
return clock_latency_ns;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
@@ -201,15 +207,13 @@ static int _get_regulator_count(struct device *dev)
struct opp_table *opp_table;
int count;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (!IS_ERR(opp_table))
- count = opp_table->regulator_count;
- else
- count = 0;
+ if (IS_ERR(opp_table))
+ return 0;
- rcu_read_unlock();
+ count = opp_table->regulator_count;
+
+ dev_pm_opp_put_opp_table(opp_table);
return count;
}
@@ -248,13 +252,11 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
if (!uV)
goto free_regulators;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- rcu_read_unlock();
+ if (IS_ERR(opp_table))
goto free_uV;
- }
+
+ rcu_read_lock();
memcpy(regulators, opp_table->regulators, count * sizeof(*regulators));
@@ -274,6 +276,7 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
}
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
/*
* The caller needs to ensure that opp_table (and hence the regulator)
@@ -323,17 +326,15 @@ unsigned long dev_pm_opp_get_suspend_opp_freq(struct device *dev)
struct opp_table *opp_table;
unsigned long freq = 0;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table) || !opp_table->suspend_opp ||
- !opp_table->suspend_opp->available)
- goto unlock;
+ if (IS_ERR(opp_table))
+ return 0;
- freq = dev_pm_opp_get_freq(opp_table->suspend_opp);
+ if (opp_table->suspend_opp && opp_table->suspend_opp->available)
+ freq = dev_pm_opp_get_freq(opp_table->suspend_opp);
+
+ dev_pm_opp_put_opp_table(opp_table);
-unlock:
- rcu_read_unlock();
return freq;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_freq);
@@ -353,23 +354,24 @@ int dev_pm_opp_get_opp_count(struct device *dev)
struct dev_pm_opp *temp_opp;
int count = 0;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
count = PTR_ERR(opp_table);
dev_err(dev, "%s: OPP table not found (%d)\n",
__func__, count);
- goto out_unlock;
+ return count;
}
+ rcu_read_lock();
+
list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
if (temp_opp->available)
count++;
}
-out_unlock:
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
+
return count;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
@@ -404,17 +406,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
struct opp_table *opp_table;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
int r = PTR_ERR(opp_table);
dev_err(dev, "%s: OPP table not found (%d)\n", __func__, r);
- rcu_read_unlock();
return ERR_PTR(r);
}
+ rcu_read_lock();
+
list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
if (temp_opp->available == available &&
temp_opp->rate == freq) {
@@ -427,6 +428,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
}
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return opp;
}
@@ -480,17 +482,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
return ERR_PTR(-EINVAL);
}
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- rcu_read_unlock();
+ if (IS_ERR(opp_table))
return ERR_CAST(opp_table);
- }
+
+ rcu_read_lock();
opp = _find_freq_ceil(opp_table, freq);
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return opp;
}
@@ -525,13 +526,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
return ERR_PTR(-EINVAL);
}
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- rcu_read_unlock();
+ if (IS_ERR(opp_table))
return ERR_CAST(opp_table);
- }
+
+ rcu_read_lock();
list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
if (temp_opp->available) {
@@ -547,6 +546,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
if (!IS_ERR(opp))
dev_pm_opp_get(opp);
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
if (!IS_ERR(opp))
*freq = opp->rate;
@@ -564,22 +564,18 @@ static struct clk *_get_opp_clk(struct device *dev)
struct opp_table *opp_table;
struct clk *clk;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
dev_err(dev, "%s: device opp doesn't exist\n", __func__);
- clk = ERR_CAST(opp_table);
- goto unlock;
+ return ERR_CAST(opp_table);
}
clk = opp_table->clk;
if (IS_ERR(clk))
dev_err(dev, "%s: No clock available for the device\n",
__func__);
+ dev_pm_opp_put_opp_table(opp_table);
-unlock:
- rcu_read_unlock();
return clk;
}
@@ -715,15 +711,14 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
return 0;
}
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
dev_err(dev, "%s: device opp doesn't exist\n", __func__);
- rcu_read_unlock();
return PTR_ERR(opp_table);
}
+ rcu_read_lock();
+
old_opp = _find_freq_ceil(opp_table, &old_freq);
if (IS_ERR(old_opp)) {
dev_err(dev, "%s: failed to find current OPP for freq %lu (%ld)\n",
@@ -738,6 +733,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
if (!IS_ERR(old_opp))
dev_pm_opp_put(old_opp);
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return ret;
}
@@ -752,6 +748,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
if (!IS_ERR(old_opp))
dev_pm_opp_put(old_opp);
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return _generic_set_opp_clk_only(dev, clk, old_freq, freq);
}
@@ -780,6 +777,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
if (!IS_ERR(old_opp))
dev_pm_opp_put(old_opp);
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return set_opp(data);
}
@@ -893,11 +891,9 @@ struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
/* Hold our table modification lock here */
mutex_lock(&opp_table_lock);
- opp_table = _find_opp_table(dev);
- if (!IS_ERR(opp_table)) {
- _get_opp_table_kref(opp_table);
+ opp_table = _find_opp_table_unlocked(dev);
+ if (!IS_ERR(opp_table))
goto unlock;
- }
opp_table = _allocate_opp_table(dev);
@@ -1004,12 +1000,9 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
struct opp_table *opp_table;
bool found = false;
- /* Hold our table modification lock here */
- mutex_lock(&opp_table_lock);
-
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table))
- goto unlock;
+ return;
mutex_lock(&opp_table->lock);
@@ -1022,15 +1015,14 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
mutex_unlock(&opp_table->lock);
- if (!found) {
+ if (found) {
+ dev_pm_opp_put(opp);
+ } else {
dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
__func__, freq);
- goto unlock;
}
- dev_pm_opp_put(opp);
-unlock:
- mutex_unlock(&opp_table_lock);
+ dev_pm_opp_put_opp_table(opp_table);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
@@ -1648,14 +1640,12 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
if (!new_opp)
return -ENOMEM;
- mutex_lock(&opp_table_lock);
-
/* Find the opp_table */
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
r = PTR_ERR(opp_table);
dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
- goto unlock;
+ goto free_opp;
}
mutex_lock(&opp_table->lock);
@@ -1668,8 +1658,6 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
}
}
- mutex_unlock(&opp_table->lock);
-
if (IS_ERR(opp)) {
r = PTR_ERR(opp);
goto unlock;
@@ -1685,7 +1673,6 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
new_opp->available = availability_req;
list_replace_rcu(&opp->node, &new_opp->node);
- mutex_unlock(&opp_table_lock);
call_srcu(&opp_table->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
/* Notify the change of the OPP availability */
@@ -1696,10 +1683,14 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
srcu_notifier_call_chain(&opp_table->srcu_head,
OPP_EVENT_DISABLE, new_opp);
+ mutex_unlock(&opp_table->lock);
+ dev_pm_opp_put_opp_table(opp_table);
return 0;
unlock:
- mutex_unlock(&opp_table_lock);
+ mutex_unlock(&opp_table->lock);
+ dev_pm_opp_put_opp_table(opp_table);
+free_opp:
kfree(new_opp);
return r;
}
@@ -1767,18 +1758,16 @@ int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb)
struct opp_table *opp_table;
int ret;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- ret = PTR_ERR(opp_table);
- goto unlock;
- }
+ if (IS_ERR(opp_table))
+ return PTR_ERR(opp_table);
+
+ rcu_read_lock();
ret = srcu_notifier_chain_register(&opp_table->srcu_head, nb);
-unlock:
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return ret;
}
@@ -1797,18 +1786,14 @@ int dev_pm_opp_unregister_notifier(struct device *dev,
struct opp_table *opp_table;
int ret;
- rcu_read_lock();
-
opp_table = _find_opp_table(dev);
- if (IS_ERR(opp_table)) {
- ret = PTR_ERR(opp_table);
- goto unlock;
- }
+ if (IS_ERR(opp_table))
+ return PTR_ERR(opp_table);
ret = srcu_notifier_chain_unregister(&opp_table->srcu_head, nb);
-unlock:
rcu_read_unlock();
+ dev_pm_opp_put_opp_table(opp_table);
return ret;
}
@@ -1839,9 +1824,6 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all)
{
struct opp_table *opp_table;
- /* Hold our table modification lock here */
- mutex_lock(&opp_table_lock);
-
/* Check for existing table for 'dev' */
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
@@ -1852,13 +1834,12 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all)
IS_ERR_OR_NULL(dev) ?
"Invalid device" : dev_name(dev),
error);
- goto unlock;
+ return;
}
_dev_pm_opp_remove_table(opp_table, dev, remove_all);
-unlock:
- mutex_unlock(&opp_table_lock);
+ dev_pm_opp_put_opp_table(opp_table);
}
/**
diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c
index adef788862d5..df29f08eecc4 100644
--- a/drivers/base/power/opp/cpu.c
+++ b/drivers/base/power/opp/cpu.c
@@ -174,13 +174,9 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
struct device *dev;
int cpu, ret = 0;
- mutex_lock(&opp_table_lock);
-
opp_table = _find_opp_table(cpu_dev);
- if (IS_ERR(opp_table)) {
- ret = PTR_ERR(opp_table);
- goto unlock;
- }
+ if (IS_ERR(opp_table))
+ return PTR_ERR(opp_table);
for_each_cpu(cpu, cpumask) {
if (cpu == cpu_dev->id)
@@ -203,8 +199,8 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
/* Mark opp-table as multiple CPUs are sharing it now */
opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
}
-unlock:
- mutex_unlock(&opp_table_lock);
+
+ dev_pm_opp_put_opp_table(opp_table);
return ret;
}
@@ -232,17 +228,13 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
struct opp_table *opp_table;
int ret = 0;
- mutex_lock(&opp_table_lock);
-
opp_table = _find_opp_table(cpu_dev);
- if (IS_ERR(opp_table)) {
- ret = PTR_ERR(opp_table);
- goto unlock;
- }
+ if (IS_ERR(opp_table))
+ return PTR_ERR(opp_table);
if (opp_table->shared_opp == OPP_TABLE_ACCESS_UNKNOWN) {
ret = -EINVAL;
- goto unlock;
+ goto put_opp_table;
}
cpumask_clear(cpumask);
@@ -254,8 +246,8 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
cpumask_set_cpu(cpu_dev->id, cpumask);
}
-unlock:
- mutex_unlock(&opp_table_lock);
+put_opp_table:
+ dev_pm_opp_put_opp_table(opp_table);
return ret;
}