PM / devfreq: Various Fixes to cpufreq based passive governor

With the passive governor, the cpu based scaling can PROBE_DEFER due to the fact that CPU policy are not ready.
The cpufreq passive unregister notifier is called both from the GOV_START errors and for the GOV_STOP and assume the notifier is successfully registred every time. With GOV_START failing it's wrong to loop over each possible CPU since the register path has failed for some CPU policy not ready. Change the logic and unregister the notifer based on the current allocated parent_cpu_data list to correctly handle errors and the governor unregister path.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 39 +++++++++++++-----------------
 1 file changed, 17 insertions(+), 22 deletions(-)

drivers/devfreq/governor_passive.c +0 -0

index 72c67979ebe1..95de336f20d5 100644

drivers/devfreq/governor_passive.c +13 -22

+	list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+		list_del(&parent_cpu_data->node);
+
+		if (parent_cpu_data->opp_table)
+			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+		kfree(parent_cpu_data);
+	}
+}
+
 static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
 						struct opp_table *p_opp_table,
 						struct opp_table *opp_table,

@@ -222,8 +236,7 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 {
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
-	struct devfreq_cpu_data *parent_cpu_data;
-	int cpu, ret = 0;
+	int ret;
 
 	if (p_data->nb.notifier_call) {
 		ret = cpufreq_unregister_notifier(&p_data->nb,

@@ -232,27 +245,9 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 			return ret;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-		if (!policy) {
-			ret = -EINVAL;
-			continue;
-		}
-
-		parent_cpu_data = get_parent_cpu_data(p_data, policy);
-		if (!parent_cpu_data) {
-			cpufreq_cpu_put(policy);
-			continue;
-		}
-
-		list_del(&parent_cpu_data->node);
-		if (parent_cpu_data->opp_table)
-			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
-		kfree(parent_cpu_data);
-		cpufreq_cpu_put(policy);
-	}
+	delete_parent_cpu_data(p_data);
 
-	return ret;
+	return 0;
 }
 
 static int cpufreq_passive_register_notifier(struct devfreq *devfreq)

Quoted 21 lines · Christian 'Ansuel' Marangi

With the passive governor, the cpu based scaling can PROBE_DEFER due to the fact that CPU policy are not ready.
The cpufreq passive unregister notifier is called both from the GOV_START errors and for the GOV_STOP and assume the notifier is successfully registred every time. With GOV_START failing it's wrong to loop over each possible CPU since the register path has failed for some CPU policy not ready. Change the logic and unregister the notifer based on the current allocated parent_cpu_data list to correctly handle errors and the governor unregister path.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 39 +++++++++++++-----------------
 1 file changed, 17 insertions(+), 22 deletions(-)

drivers/devfreq/governor_passive.c +0 -0

index 72c67979ebe1..95de336f20d5 100644

drivers/devfreq/governor_passive.c get_parent_cpu_data(struct devfreq_passive_data *p_data, · line 40

Quoted 7 lines

drivers/devfreq/governor_passive.c +4 -0

@@ -34,6 +34,20 @@ get_parent_cpu_data(struct devfreq_passive_data *p_data,
 	return NULL;
 }
 
+static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
+{
+	struct devfreq_cpu_data *parent_cpu_data, *tmp;
+

Need to add the validation checking of argument as following:

	if (!p_data)
		return;

Quoted 53 lines

drivers/devfreq/governor_passive.c +13 -22

+	list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+		list_del(&parent_cpu_data->node);
+
+		if (parent_cpu_data->opp_table)
+			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+		kfree(parent_cpu_data);
+	}
+}
+
 static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
 						struct opp_table *p_opp_table,
 						struct opp_table *opp_table,

@@ -222,8 +236,7 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 {
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
-	struct devfreq_cpu_data *parent_cpu_data;
-	int cpu, ret = 0;
+	int ret;
 
 	if (p_data->nb.notifier_call) {
 		ret = cpufreq_unregister_notifier(&p_data->nb,

@@ -232,27 +245,9 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 			return ret;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-		if (!policy) {
-			ret = -EINVAL;
-			continue;
-		}
-
-		parent_cpu_data = get_parent_cpu_data(p_data, policy);
-		if (!parent_cpu_data) {
-			cpufreq_cpu_put(policy);
-			continue;
-		}
-
-		list_del(&parent_cpu_data->node);
-		if (parent_cpu_data->opp_table)
-			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
-		kfree(parent_cpu_data);
-		cpufreq_cpu_put(policy);
-	}
+	delete_parent_cpu_data(p_data);
 
-	return ret;
+	return 0;
 }
 
 static int cpufreq_passive_register_notifier(struct devfreq *devfreq)

Signature · 3 lines

Best Regards,
Samsung Electronics
Chanwoo Choi

Quoted 33 lines · Chanwoo Choi

Quoted 22 lines · Christian 'Ansuel' Marangi

With the passive governor, the cpu based scaling can PROBE_DEFER due to the fact that CPU policy are not ready.

The cpufreq passive unregister notifier is called both from the GOV_START errors and for the GOV_STOP and assume the notifier is successfully registred every time. With GOV_START failing it's wrong to loop over each possible CPU since the register path has failed for some CPU policy not ready. Change the logic and unregister the notifer based on the current allocated parent_cpu_data list to correctly handle errors and the governor unregister path.>>>

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 39 +++++++++++++-----------------
 1 file changed, 17 insertions(+), 22 deletions(-)

drivers/devfreq/governor_passive.c +0 -0

index 72c67979ebe1..95de336f20d5 100644

drivers/devfreq/governor_passive.c get_parent_cpu_data(struct devfreq_passive_data *p_data, · line 40

Quoted 7 lines

drivers/devfreq/governor_passive.c +4 -0

@@ -34,6 +34,20 @@ get_parent_cpu_data(struct devfreq_passive_data *p_data,
 	return NULL;
 }
 
+static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
+{
+	struct devfreq_cpu_data *parent_cpu_data, *tmp;
+

Need to add the validation checking of argument as following:

Quoted 3 lines

	if (!p_data)
		return;

Considering this is called only by cpufreq_passive_unregister_notifier and cpufreq_passive_unregister_notifier is called only by devfreq_passive_event_handler where the check is already done, isn't that redundant.
We should never reach delete_parent_cpu_data with no p_data.
(Unless you want to use that function somewhere else)

Quoted 60 lines

Quoted 54 lines

drivers/devfreq/governor_passive.c +13 -22

+	list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+		list_del(&parent_cpu_data->node);
+
+		if (parent_cpu_data->opp_table)
+			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+		kfree(parent_cpu_data);
+	}
+}
+
 static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
 						struct opp_table *p_opp_table,
 						struct opp_table *opp_table,

@@ -222,8 +236,7 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 {
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
-	struct devfreq_cpu_data *parent_cpu_data;
-	int cpu, ret = 0;
+	int ret;
 
 	if (p_data->nb.notifier_call) {
 		ret = cpufreq_unregister_notifier(&p_data->nb,

@@ -232,27 +245,9 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 			return ret;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-		if (!policy) {
-			ret = -EINVAL;
-			continue;
-		}
-
-		parent_cpu_data = get_parent_cpu_data(p_data, policy);
-		if (!parent_cpu_data) {
-			cpufreq_cpu_put(policy);
-			continue;
-		}
-
-		list_del(&parent_cpu_data->node);
-		if (parent_cpu_data->opp_table)
-			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
-		kfree(parent_cpu_data);
-		cpufreq_cpu_put(policy);
-	}
+	delete_parent_cpu_data(p_data);
 
-	return ret;
+	return 0;
 }
 
 static int cpufreq_passive_register_notifier(struct devfreq *devfreq)

Signature · 3 lines

Best Regards,
Samsung Electronics
Chanwoo Choi

When the cpufreq passive register path from the passive governor fails, the cpufreq_passive_unregister is called and a kernel WARNING is always reported.
This is caused by the fact that the devfreq driver already call the governor unregister with the GOV_STOP, for this reason the second cpufreq_passive_unregister always return error and a WARN is printed from the WARN_ON function.
Remove the unregister call from the error handling of the cpufreq register notifier as it's fundamentally wrong and already handled by the devfreq core code.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 1 -
 1 file changed, 1 deletion(-)

drivers/devfreq/governor_passive.c +0 -0

index 95de336f20d5..dcc9dd518197 100644

Quoted 27 lines · Christian 'Ansuel' Marangi

When the cpufreq passive register path from the passive governor fails, the cpufreq_passive_unregister is called and a kernel WARNING is always reported.
This is caused by the fact that the devfreq driver already call the governor unregister with the GOV_STOP, for this reason the second cpufreq_passive_unregister always return error and a WARN is printed from the WARN_ON function.
Remove the unregister call from the error handling of the cpufreq register notifier as it's fundamentally wrong and already handled by the devfreq core code.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 1 -
 1 file changed, 1 deletion(-)

drivers/devfreq/governor_passive.c +0 -1

index 95de336f20d5..dcc9dd518197 100644
@@ -331,7 +331,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
 err_put_policy:
 	cpufreq_cpu_put(policy);
 err:
-	WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
 

drivers/devfreq/governor_passive.c static int cpufreq_passive_register_notifier(struct devfreq *devfreq) · line 336

Quoted 2 lines

drivers/devfreq/governor_passive.c +0 -0

 	return ret;
 }

I think that it is necessary to free the resource when error happen.

Also, after merging the your patch1, I think that cpufreq_passive_unregister_notifier(devfreq) will not return error. Instead, just 0 for success.

Instead, 'err_free_cpu_data' and 'err_put_policy' goto statement are wrong exception handling. If fix the exception handling code in cpufreq_passive_register_notifier as following and with your patch1, I'll handle the resource for free/un-registration when error happen during cpufreq_passive_register_notifier.

drivers/devfreq/governor_passive.c +4 -7

index a35b39ac656c..0246e0731fc0 100644
@@ -289,22 +289,23 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
                parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
                                                GFP_KERNEL);
                if (!parent_cpu_data) {
+                       cpufreq_cpu_put(policy);
                        ret = -ENOMEM;
-                       goto err_put_policy;
+                       goto err;
                }
 
                cpu_dev = get_cpu_device(cpu);
                if (!cpu_dev) {
                        dev_err(dev, "failed to get cpu device\n");
                        ret = -ENODEV;
-                       goto err_free_cpu_data;
+                       goto err;
                }
 
                opp_table = dev_pm_opp_get_opp_table(cpu_dev);
                if (IS_ERR(opp_table)) {
                        dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
                        ret = PTR_ERR(opp_table);
-                       goto err_free_cpu_data;
+                       goto err;
                }
 
                parent_cpu_data->dev = cpu_dev;

@@ -326,10 +327,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
 
        return ret;
 
-err_free_cpu_data:
-       kfree(parent_cpu_data);
-err_put_policy:
-       cpufreq_cpu_put(policy);
 err:
        WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
 

Signature · 4 lines

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi

Quoted 4 lines · Chanwoo Choi

Quoted 3 lines · Christian 'Ansuel' Marangi

When the cpufreq passive register path from the passive governor fails, the cpufreq_passive_unregister is called and a kernel WARNING is always reported.

Quoted 8 lines

Quoted 8 lines

This is caused by the fact that the devfreq driver already call the governor unregister with the GOV_STOP, for this reason the second cpufreq_passive_unregister always return error and a WARN is printed from the WARN_ON function.

Remove the unregister call from the error handling of the cpufreq register notifier as it's fundamentally wrong and already handled by the devfreq core code.

Quoted 17 lines

Quoted 17 lines

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 1 -
 1 file changed, 1 deletion(-)

drivers/devfreq/governor_passive.c +0 -1

index 95de336f20d5..dcc9dd518197 100644
@@ -331,7 +331,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
 err_put_policy:
 	cpufreq_cpu_put(policy);
 err:
-	WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
 

Quoted 4 lines

drivers/devfreq/governor_passive.c static int cpufreq_passive_register_notifier(struct devfreq *devfreq) · line 336

Quoted 2 lines

drivers/devfreq/governor_passive.c +0 -0

 	return ret;
 }

I think that it is necessary to free the resource when error happen.

Thing is that it should not be done in the register. Following the flow of the devfreq core code, if a gov fails to START, the gov STOP is called and we correctly free our resources. In the current implementation we call the free 2 times and the second time will always print error as the notifier is already unregistered.

Quoted 2 lines

Also, after merging the your patch1, I think that cpufreq_passive_unregister_notifier(devfreq) will not return error. Instead, just 0 for success.

With path1 we removed the error with the parent_cpu_data deletion but the unregister error is still there.

Quoted 1 line

Quoted 5 lines

Instead, 'err_free_cpu_data' and 'err_put_policy' goto statement are wrong exception handling. If fix the exception handling code in cpufreq_passive_register_notifier as following and with your patch1, I'll handle the resource for free/un-registration when error happen during cpufreq_passive_register_notifier.

Don't know the main problem here is calling unregister 2 times.

Quoted 6 lines · Ansuel Smith

Quoted 4 lines · Chanwoo Choi

Quoted 3 lines · Christian 'Ansuel' Marangi

When the cpufreq passive register path from the passive governor fails, the cpufreq_passive_unregister is called and a kernel WARNING is always reported.

Quoted 8 lines

Quoted 8 lines

Quoted 8 lines

This is caused by the fact that the devfreq driver already call the governor unregister with the GOV_STOP, for this reason the second cpufreq_passive_unregister always return error and a WARN is printed from the WARN_ON function.

Remove the unregister call from the error handling of the cpufreq register notifier as it's fundamentally wrong and already handled by the devfreq core code.

If possible, could you make the patch description more simply?

Quoted 35 lines

Quoted 17 lines

Quoted 17 lines

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/governor_passive.c | 1 -
 1 file changed, 1 deletion(-)

drivers/devfreq/governor_passive.c +0 -1

index 95de336f20d5..dcc9dd518197 100644
@@ -331,7 +331,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
 err_put_policy:
 	cpufreq_cpu_put(policy);
 err:
-	WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
 

Quoted 4 lines

drivers/devfreq/governor_passive.c static int cpufreq_passive_register_notifier(struct devfreq *devfreq) · line 332

Quoted 2 lines

drivers/devfreq/governor_passive.c +0 -0

 	return ret;
 }

I think that it is necessary to free the resource when error happen.

Thing is that it should not be done in the register. Following the flow of the devfreq core code, if a gov fails to START, the gov STOP is called and we correctly free our resources. In the current implementation we call the free 2 times and the second time will always print error as the notifier is already unregistered.

Quoted 2 lines

Also, after merging the your patch1, I think that cpufreq_passive_unregister_notifier(devfreq) will not return error. Instead, just 0 for success.

With path1 we removed the error with the parent_cpu_data deletion but the unregister error is still there.

Quoted 1 line

Quoted 7 lines

Quoted 5 lines

Instead, 'err_free_cpu_data' and 'err_put_policy' goto statement are wrong exception handling. If fix the exception handling code in cpufreq_passive_register_notifier as following and with your patch1, I'll handle the resource for free/un-registration when error happen during cpufreq_passive_register_notifier.

Don't know the main problem here is calling unregister 2 times.

Ah. I understood. To fix the error path handling with unregister function is called twice, I think that need to to fix it as following:

drivers/devfreq/governor_passive.c +6 -3

index a35b39ac656c..8f38a63beefc 100644
@@ -289,22 +289,25 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
                parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
                                                GFP_KERNEL);
                if (!parent_cpu_data) {
+                       cpufreq_cpu_put(policy);
                        ret = -ENOMEM;
-                       goto err_put_policy;
+                       goto err;
                }
 
                cpu_dev = get_cpu_device(cpu);
                if (!cpu_dev) {
                        dev_err(dev, "failed to get cpu device\n");
+                       cpufreq_cpu_put(policy);
                        ret = -ENODEV;
-                       goto err_free_cpu_data;
+                       goto err;
                }
 
                opp_table = dev_pm_opp_get_opp_table(cpu_dev);
                if (IS_ERR(opp_table)) {
                        dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
+                       cpufreq_cpu_put(policy);
                        ret = PTR_ERR(opp_table);
-                       goto err_free_cpu_data;
+                       goto err;
                }
 
                parent_cpu_data->dev = cpu_dev;

drivers/devfreq/governor_passive.c +0 -4

-err_put_policy:
-       cpufreq_cpu_put(policy);
 err:
-       WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
-
        return ret;
 }
 

Signature · 4 lines

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi

Currently we reference the freq_table to the profile defined one and we make changes on it. Devfreq never supported PROBE_DEFER before the cpu based scaling support to the passive governor and assumed that a devfreq device could only had error and be done with it.
Now that a device can PROBE_DEFER a rework to the freq_table logic is required.

If a device PROBE_DEFER on the GOV_START, the freq_table is already set in the device profile struct and its init is skipped. This is due to the fact that it's common for devs to declare this kind of struct static. This cause the devfreq logic to find a freq table declared (freq_table not NULL) with random data and poiting to the old addrs freed by devm. This problem CAN be solved by devs by clearing the freq_table in their profile struct on driver exit path but it should not be trusted and it looks to use a flawed logic.

A better solution is to move the freq_table and max_state to the devfreq struct and never change the profile struct.
This permit to correctly handle PROBE_DEFER since the devfreq struct is reallocated and contains new values.
Also the profile struct should only be used to init the driver and should not be used by the devfreq to write the freq_table if it's not provided by the driver.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c          | 71 ++++++++++++++----------------
 drivers/devfreq/governor_passive.c | 14 +++---
 include/linux/devfreq.h            |  4 ++
 3 files changed, 45 insertions(+), 44 deletions(-)

drivers/devfreq/devfreq.c +34 -37

index 01474daf4548..2e2b3b414d67 100644
@@ -123,7 +123,7 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 			    unsigned long *min_freq,
 			    unsigned long *max_freq)
 {
-	unsigned long *freq_table = devfreq->profile->freq_table;
+	unsigned long *freq_table = devfreq->freq_table;
 	s32 qos_min_freq, qos_max_freq;
 
 	lockdep_assert_held(&devfreq->lock);

@@ -133,11 +133,11 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 	 * The devfreq drivers can initialize this in either ascending or
 	 * descending order and devfreq core supports both.
 	 */
-	if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
+	if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
 		*min_freq = freq_table[0];
-		*max_freq = freq_table[devfreq->profile->max_state - 1];
+		*max_freq = freq_table[devfreq->max_state - 1];
 	} else {
-		*min_freq = freq_table[devfreq->profile->max_state - 1];
+		*min_freq = freq_table[devfreq->max_state - 1];
 		*max_freq = freq_table[0];
 	}
 

@@ -169,8 +169,8 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev;
 
-	for (lev = 0; lev < devfreq->profile->max_state; lev++)
-		if (freq == devfreq->profile->freq_table[lev])
+	for (lev = 0; lev < devfreq->max_state; lev++)
+		if (freq == devfreq->freq_table[lev])
 			return lev;
 
 	return -EINVAL;

@@ -178,7 +178,6 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 
 static int set_freq_table(struct devfreq *devfreq)
 {
-	struct devfreq_dev_profile *profile = devfreq->profile;
 	struct dev_pm_opp *opp;
 	unsigned long freq;
 	int i, count;

@@ -188,25 +187,22 @@ static int set_freq_table(struct devfreq *devfreq)
 	if (count <= 0)
 		return -EINVAL;
 
-	profile->max_state = count;
-	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					profile->max_state,
-					sizeof(*profile->freq_table),
-					GFP_KERNEL);
-	if (!profile->freq_table) {
-		profile->max_state = 0;
+	devfreq->max_state = count;
+	devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
+					   devfreq->max_state,
+					   sizeof(*devfreq->freq_table),
+					   GFP_KERNEL);
+	if (!devfreq->freq_table)
 		return -ENOMEM;
-	}
 
-	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
+	for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
 		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 		if (IS_ERR(opp)) {
-			devm_kfree(devfreq->dev.parent, profile->freq_table);
-			profile->max_state = 0;
+			devm_kfree(devfreq->dev.parent, devfreq->freq_table);
 			return PTR_ERR(opp);
 		}
 		dev_pm_opp_put(opp);
-		profile->freq_table[i] = freq;
+		devfreq->freq_table[i] = freq;
 	}
 
 	return 0;

@@ -246,7 +242,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	if (lev != prev_lev) {
 		devfreq->stats.trans_table[
-			(prev_lev * devfreq->profile->max_state) + lev]++;
+			(prev_lev * devfreq->max_state) + lev]++;
 		devfreq->stats.total_trans++;
 	}
 

@@ -835,6 +831,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		if (err < 0)
 			goto err_dev;
 		mutex_lock(&devfreq->lock);
+	} else {
+		devfreq->freq_table = devfreq->profile->freq_table;
+		devfreq->max_state = devfreq->profile->max_state;
 	}
 
 	devfreq->scaling_min_freq = find_available_min_freq(devfreq);

@@ -870,8 +869,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 			array3_size(sizeof(unsigned int),
-				    devfreq->profile->max_state,
-				    devfreq->profile->max_state),
+				    devfreq->max_state,
+				    devfreq->max_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.trans_table) {
 		mutex_unlock(&devfreq->lock);

@@ -880,7 +879,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
-			devfreq->profile->max_state,
+			devfreq->max_state,
 			sizeof(*devfreq->stats.time_in_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.time_in_state) {

@@ -1665,9 +1664,9 @@ static ssize_t available_frequencies_show(struct device *d,
 
 	mutex_lock(&df->lock);
 
-	for (i = 0; i < df->profile->max_state; i++)
+	for (i = 0; i < df->max_state; i++)
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				"%lu ", df->profile->freq_table[i]);
+				"%lu ", df->freq_table[i]);
 
 	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */

@@ -1690,7 +1689,7 @@ static ssize_t trans_stat_show(struct device *dev,
 
 	if (!df->profile)
 		return -EINVAL;
-	max_state = df->profile->max_state;
+	max_state = df->max_state;
 
 	if (max_state == 0)
 		return sprintf(buf, "Not Supported.\n");

@@ -1707,19 +1706,17 @@ static ssize_t trans_stat_show(struct device *dev,
 	len += sprintf(buf + len, "           :");
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				df->profile->freq_table[i]);
+				df->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (df->profile->freq_table[i]
-					== df->previous_freq) {
+		if (df->freq_table[i] == df->previous_freq)
 			len += sprintf(buf + len, "*");
-		} else {
+		else
 			len += sprintf(buf + len, " ");
-		}
-		len += sprintf(buf + len, "%10lu:",
-				df->profile->freq_table[i]);
+
+		len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
 				df->stats.trans_table[(i * max_state) + j]);

@@ -1743,7 +1740,7 @@ static ssize_t trans_stat_store(struct device *dev,
 	if (!df->profile)
 		return -EINVAL;
 
-	if (df->profile->max_state == 0)
+	if (df->max_state == 0)
 		return count;
 
 	err = kstrtoint(buf, 10, &value);

@@ -1751,11 +1748,11 @@ static ssize_t trans_stat_store(struct device *dev,
 		return -EINVAL;
 
 	mutex_lock(&df->lock);
-	memset(df->stats.time_in_state, 0, (df->profile->max_state *
+	memset(df->stats.time_in_state, 0, (df->max_state *
 					sizeof(*df->stats.time_in_state)));
 	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
-					df->profile->max_state,
-					df->profile->max_state));
+					df->max_state,
+					df->max_state));
 	df->stats.total_trans = 0;
 	df->stats.last_update = get_jiffies_64();
 	mutex_unlock(&df->lock);

drivers/devfreq/governor_passive.c +7 -7

index dcc9dd518197..1810966fd61d 100644
@@ -145,18 +145,18 @@ static int get_target_freq_with_devfreq(struct devfreq *devfreq,
 		goto out;
 
 	/* Use interpolation if required opps is not available */
-	for (i = 0; i < parent_devfreq->profile->max_state; i++)
-		if (parent_devfreq->profile->freq_table[i] == *freq)
+	for (i = 0; i < parent_devfreq->max_state; i++)
+		if (parent_devfreq->freq_table[i] == *freq)
 			break;
 
-	if (i == parent_devfreq->profile->max_state)
+	if (i == parent_devfreq->max_state)
 		return -EINVAL;
 
-	if (i < devfreq->profile->max_state) {
-		child_freq = devfreq->profile->freq_table[i];
+	if (i < devfreq->max_state) {
+		child_freq = devfreq->freq_table[i];
 	} else {
-		count = devfreq->profile->max_state;
-		child_freq = devfreq->profile->freq_table[count - 1];
+		count = devfreq->max_state;
+		child_freq = devfreq->freq_table[count - 1];
 	}
 
 out:

include/linux/devfreq.h +4 -0

index dc10bee75a72..770a7532655c 100644
@@ -185,6 +185,10 @@ struct devfreq {
 	struct notifier_block nb;
 	struct delayed_work work;
 
+	/* devfreq local freq_table */
+	unsigned long *freq_table;
+	unsigned int max_state;
+
 	unsigned long previous_freq;
 	struct devfreq_dev_status last_status;
 

Hi,

Thanks for the good catch.

I think that this patch fixes issue of commit 0ec09ac2cebe ("PM / devfreq: Set the freq_table of devfreq device").

When some devfreq driver without using passive governor faces on the all errors including PROBE_DEFER after executing devfreq_add_device, this issue will happen.

Also need to check the devfreq device driver using freq_table which was allocated dynamically. In case of devfreq/drivers/exynos-bus.c used the devfreq->profile->freq_table after devfreq_add_device.

Quoted 16 lines · Christian 'Ansuel' Marangi

Currently we reference the freq_table to the profile defined one and we make changes on it. Devfreq never supported PROBE_DEFER before the cpu based scaling support to the passive governor and assumed that a devfreq device could only had error and be done with it.
Now that a device can PROBE_DEFER a rework to the freq_table logic is required.

If a device PROBE_DEFER on the GOV_START, the freq_table is already set in the device profile struct and its init is skipped. This is due to the fact that it's common for devs to declare this kind of struct static. This cause the devfreq logic to find a freq table declared (freq_table not NULL) with random data and poiting to the old addrs freed by devm. This problem CAN be solved by devs by clearing the freq_table in their profile struct on driver exit path but it should not be trusted and it looks to use a flawed logic.

Quoted 8 lines

A better solution is to move the freq_table and max_state to the devfreq struct and never change the profile struct.
This permit to correctly handle PROBE_DEFER since the devfreq struct is reallocated and contains new values.
Also the profile struct should only be used to init the driver and should not be used by the devfreq to write the freq_table if it's not provided by the driver.

If possible, could you explain the patch description more simply? Maybe, just focus on the 'freq_table' issue by device managed functions (devs).

Quoted 245 lines

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c          | 71 ++++++++++++++----------------
 drivers/devfreq/governor_passive.c | 14 +++---
 include/linux/devfreq.h            |  4 ++
 3 files changed, 45 insertions(+), 44 deletions(-)

drivers/devfreq/devfreq.c +34 -37

index 01474daf4548..2e2b3b414d67 100644
@@ -123,7 +123,7 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 			    unsigned long *min_freq,
 			    unsigned long *max_freq)
 {
-	unsigned long *freq_table = devfreq->profile->freq_table;
+	unsigned long *freq_table = devfreq->freq_table;
 	s32 qos_min_freq, qos_max_freq;
 
 	lockdep_assert_held(&devfreq->lock);

@@ -133,11 +133,11 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 	 * The devfreq drivers can initialize this in either ascending or
 	 * descending order and devfreq core supports both.
 	 */
-	if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
+	if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
 		*min_freq = freq_table[0];
-		*max_freq = freq_table[devfreq->profile->max_state - 1];
+		*max_freq = freq_table[devfreq->max_state - 1];
 	} else {
-		*min_freq = freq_table[devfreq->profile->max_state - 1];
+		*min_freq = freq_table[devfreq->max_state - 1];
 		*max_freq = freq_table[0];
 	}
 

@@ -169,8 +169,8 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev;
 
-	for (lev = 0; lev < devfreq->profile->max_state; lev++)
-		if (freq == devfreq->profile->freq_table[lev])
+	for (lev = 0; lev < devfreq->max_state; lev++)
+		if (freq == devfreq->freq_table[lev])
 			return lev;
 
 	return -EINVAL;

@@ -178,7 +178,6 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 
 static int set_freq_table(struct devfreq *devfreq)
 {
-	struct devfreq_dev_profile *profile = devfreq->profile;
 	struct dev_pm_opp *opp;
 	unsigned long freq;
 	int i, count;

@@ -188,25 +187,22 @@ static int set_freq_table(struct devfreq *devfreq)
 	if (count <= 0)
 		return -EINVAL;
 
-	profile->max_state = count;
-	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					profile->max_state,
-					sizeof(*profile->freq_table),
-					GFP_KERNEL);
-	if (!profile->freq_table) {
-		profile->max_state = 0;
+	devfreq->max_state = count;
+	devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
+					   devfreq->max_state,
+					   sizeof(*devfreq->freq_table),
+					   GFP_KERNEL);
+	if (!devfreq->freq_table)
 		return -ENOMEM;
-	}
 
-	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
+	for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
 		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 		if (IS_ERR(opp)) {
-			devm_kfree(devfreq->dev.parent, profile->freq_table);
-			profile->max_state = 0;
+			devm_kfree(devfreq->dev.parent, devfreq->freq_table);
 			return PTR_ERR(opp);
 		}
 		dev_pm_opp_put(opp);
-		profile->freq_table[i] = freq;
+		devfreq->freq_table[i] = freq;
 	}
 
 	return 0;

@@ -246,7 +242,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	if (lev != prev_lev) {
 		devfreq->stats.trans_table[
-			(prev_lev * devfreq->profile->max_state) + lev]++;
+			(prev_lev * devfreq->max_state) + lev]++;
 		devfreq->stats.total_trans++;
 	}
 

@@ -835,6 +831,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		if (err < 0)
 			goto err_dev;
 		mutex_lock(&devfreq->lock);
+	} else {
+		devfreq->freq_table = devfreq->profile->freq_table;
+		devfreq->max_state = devfreq->profile->max_state;
 	}
 
 	devfreq->scaling_min_freq = find_available_min_freq(devfreq);

@@ -870,8 +869,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 			array3_size(sizeof(unsigned int),
-				    devfreq->profile->max_state,
-				    devfreq->profile->max_state),
+				    devfreq->max_state,
+				    devfreq->max_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.trans_table) {
 		mutex_unlock(&devfreq->lock);

@@ -880,7 +879,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
-			devfreq->profile->max_state,
+			devfreq->max_state,
 			sizeof(*devfreq->stats.time_in_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.time_in_state) {

@@ -1665,9 +1664,9 @@ static ssize_t available_frequencies_show(struct device *d,
 
 	mutex_lock(&df->lock);
 
-	for (i = 0; i < df->profile->max_state; i++)
+	for (i = 0; i < df->max_state; i++)
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				"%lu ", df->profile->freq_table[i]);
+				"%lu ", df->freq_table[i]);
 
 	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */

@@ -1690,7 +1689,7 @@ static ssize_t trans_stat_show(struct device *dev,
 
 	if (!df->profile)
 		return -EINVAL;
-	max_state = df->profile->max_state;
+	max_state = df->max_state;
 
 	if (max_state == 0)
 		return sprintf(buf, "Not Supported.\n");

@@ -1707,19 +1706,17 @@ static ssize_t trans_stat_show(struct device *dev,
 	len += sprintf(buf + len, "           :");
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				df->profile->freq_table[i]);
+				df->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (df->profile->freq_table[i]
-					== df->previous_freq) {
+		if (df->freq_table[i] == df->previous_freq)
 			len += sprintf(buf + len, "*");
-		} else {
+		else
 			len += sprintf(buf + len, " ");
-		}
-		len += sprintf(buf + len, "%10lu:",
-				df->profile->freq_table[i]);
+
+		len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
 				df->stats.trans_table[(i * max_state) + j]);

@@ -1743,7 +1740,7 @@ static ssize_t trans_stat_store(struct device *dev,
 	if (!df->profile)
 		return -EINVAL;
 
-	if (df->profile->max_state == 0)
+	if (df->max_state == 0)
 		return count;
 
 	err = kstrtoint(buf, 10, &value);

@@ -1751,11 +1748,11 @@ static ssize_t trans_stat_store(struct device *dev,
 		return -EINVAL;
 
 	mutex_lock(&df->lock);
-	memset(df->stats.time_in_state, 0, (df->profile->max_state *
+	memset(df->stats.time_in_state, 0, (df->max_state *
 					sizeof(*df->stats.time_in_state)));
 	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
-					df->profile->max_state,
-					df->profile->max_state));
+					df->max_state,
+					df->max_state));
 	df->stats.total_trans = 0;
 	df->stats.last_update = get_jiffies_64();
 	mutex_unlock(&df->lock);

drivers/devfreq/governor_passive.c +7 -7

index dcc9dd518197..1810966fd61d 100644
@@ -145,18 +145,18 @@ static int get_target_freq_with_devfreq(struct devfreq *devfreq,
 		goto out;
 
 	/* Use interpolation if required opps is not available */
-	for (i = 0; i < parent_devfreq->profile->max_state; i++)
-		if (parent_devfreq->profile->freq_table[i] == *freq)
+	for (i = 0; i < parent_devfreq->max_state; i++)
+		if (parent_devfreq->freq_table[i] == *freq)
 			break;
 
-	if (i == parent_devfreq->profile->max_state)
+	if (i == parent_devfreq->max_state)
 		return -EINVAL;
 
-	if (i < devfreq->profile->max_state) {
-		child_freq = devfreq->profile->freq_table[i];
+	if (i < devfreq->max_state) {
+		child_freq = devfreq->freq_table[i];
 	} else {
-		count = devfreq->profile->max_state;
-		child_freq = devfreq->profile->freq_table[count - 1];
+		count = devfreq->max_state;
+		child_freq = devfreq->freq_table[count - 1];
 	}
 
 out:

include/linux/devfreq.h +4 -0

index dc10bee75a72..770a7532655c 100644
@@ -185,6 +185,10 @@ struct devfreq {
 	struct notifier_block nb;
 	struct delayed_work work;
 
+	/* devfreq local freq_table */
+	unsigned long *freq_table;
+	unsigned int max_state;
+
 	unsigned long previous_freq;
 	struct devfreq_dev_status last_status;
 

Signature · 3 lines

Best Regards,
Samsung Electronics
Chanwoo Choi

Quoted 8 lines · Chanwoo Choi

Hi,

Thanks for the good catch.

I think that this patch fixes issue of commit 0ec09ac2cebe ("PM / devfreq: Set the freq_table of devfreq device").

Should I add this to the Fixes list?

Quoted 35 lines

When some devfreq driver without using passive governor faces on the all errors including PROBE_DEFER after executing devfreq_add_device, this issue will happen.

Also need to check the devfreq device driver using freq_table which was allocated dynamically. In case of devfreq/drivers/exynos-bus.c used the devfreq->profile->freq_table after devfreq_add_device.

Quoted 24 lines · Christian 'Ansuel' Marangi

Currently we reference the freq_table to the profile defined one and we make changes on it. Devfreq never supported PROBE_DEFER before the cpu based scaling support to the passive governor and assumed that a devfreq device could only had error and be done with it.
Now that a device can PROBE_DEFER a rework to the freq_table logic is required.

If a device PROBE_DEFER on the GOV_START, the freq_table is already set in the device profile struct and its init is skipped. This is due to the fact that it's common for devs to declare this kind of struct static. This cause the devfreq logic to find a freq table declared (freq_table not NULL) with random data and poiting to the old addrs freed by devm. This problem CAN be solved by devs by clearing the freq_table in their profile struct on driver exit path but it should not be trusted and it looks to use a flawed logic.

A better solution is to move the freq_table and max_state to the devfreq struct and never change the profile struct.
This permit to correctly handle PROBE_DEFER since the devfreq struct is reallocated and contains new values.
Also the profile struct should only be used to init the driver and should not be used by the devfreq to write the freq_table if it's not provided by the driver.

Quoted 3 lines

If possible, could you explain the patch description more simply? Maybe, just focus on the 'freq_table' issue by device managed functions (devs).

Sure!

Quoted 239 lines

Quoted 239 lines

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c          | 71 ++++++++++++++----------------
 drivers/devfreq/governor_passive.c | 14 +++---
 include/linux/devfreq.h            |  4 ++
 3 files changed, 45 insertions(+), 44 deletions(-)

drivers/devfreq/devfreq.c +34 -37

index 01474daf4548..2e2b3b414d67 100644
@@ -123,7 +123,7 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 			    unsigned long *min_freq,
 			    unsigned long *max_freq)
 {
-	unsigned long *freq_table = devfreq->profile->freq_table;
+	unsigned long *freq_table = devfreq->freq_table;
 	s32 qos_min_freq, qos_max_freq;
 
 	lockdep_assert_held(&devfreq->lock);

@@ -133,11 +133,11 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
 	 * The devfreq drivers can initialize this in either ascending or
 	 * descending order and devfreq core supports both.
 	 */
-	if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
+	if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
 		*min_freq = freq_table[0];
-		*max_freq = freq_table[devfreq->profile->max_state - 1];
+		*max_freq = freq_table[devfreq->max_state - 1];
 	} else {
-		*min_freq = freq_table[devfreq->profile->max_state - 1];
+		*min_freq = freq_table[devfreq->max_state - 1];
 		*max_freq = freq_table[0];
 	}
 

@@ -169,8 +169,8 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev;
 
-	for (lev = 0; lev < devfreq->profile->max_state; lev++)
-		if (freq == devfreq->profile->freq_table[lev])
+	for (lev = 0; lev < devfreq->max_state; lev++)
+		if (freq == devfreq->freq_table[lev])
 			return lev;
 
 	return -EINVAL;

@@ -178,7 +178,6 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 
 static int set_freq_table(struct devfreq *devfreq)
 {
-	struct devfreq_dev_profile *profile = devfreq->profile;
 	struct dev_pm_opp *opp;
 	unsigned long freq;
 	int i, count;

@@ -188,25 +187,22 @@ static int set_freq_table(struct devfreq *devfreq)
 	if (count <= 0)
 		return -EINVAL;
 
-	profile->max_state = count;
-	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
-					profile->max_state,
-					sizeof(*profile->freq_table),
-					GFP_KERNEL);
-	if (!profile->freq_table) {
-		profile->max_state = 0;
+	devfreq->max_state = count;
+	devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
+					   devfreq->max_state,
+					   sizeof(*devfreq->freq_table),
+					   GFP_KERNEL);
+	if (!devfreq->freq_table)
 		return -ENOMEM;
-	}
 
-	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
+	for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
 		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 		if (IS_ERR(opp)) {
-			devm_kfree(devfreq->dev.parent, profile->freq_table);
-			profile->max_state = 0;
+			devm_kfree(devfreq->dev.parent, devfreq->freq_table);
 			return PTR_ERR(opp);
 		}
 		dev_pm_opp_put(opp);
-		profile->freq_table[i] = freq;
+		devfreq->freq_table[i] = freq;
 	}
 
 	return 0;

@@ -246,7 +242,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	if (lev != prev_lev) {
 		devfreq->stats.trans_table[
-			(prev_lev * devfreq->profile->max_state) + lev]++;
+			(prev_lev * devfreq->max_state) + lev]++;
 		devfreq->stats.total_trans++;
 	}
 

@@ -835,6 +831,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		if (err < 0)
 			goto err_dev;
 		mutex_lock(&devfreq->lock);
+	} else {
+		devfreq->freq_table = devfreq->profile->freq_table;
+		devfreq->max_state = devfreq->profile->max_state;
 	}
 
 	devfreq->scaling_min_freq = find_available_min_freq(devfreq);

@@ -870,8 +869,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 			array3_size(sizeof(unsigned int),
-				    devfreq->profile->max_state,
-				    devfreq->profile->max_state),
+				    devfreq->max_state,
+				    devfreq->max_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.trans_table) {
 		mutex_unlock(&devfreq->lock);

@@ -880,7 +879,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
-			devfreq->profile->max_state,
+			devfreq->max_state,
 			sizeof(*devfreq->stats.time_in_state),
 			GFP_KERNEL);
 	if (!devfreq->stats.time_in_state) {

@@ -1665,9 +1664,9 @@ static ssize_t available_frequencies_show(struct device *d,
 
 	mutex_lock(&df->lock);
 
-	for (i = 0; i < df->profile->max_state; i++)
+	for (i = 0; i < df->max_state; i++)
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				"%lu ", df->profile->freq_table[i]);
+				"%lu ", df->freq_table[i]);
 
 	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */

@@ -1690,7 +1689,7 @@ static ssize_t trans_stat_show(struct device *dev,
 
 	if (!df->profile)
 		return -EINVAL;
-	max_state = df->profile->max_state;
+	max_state = df->max_state;
 
 	if (max_state == 0)
 		return sprintf(buf, "Not Supported.\n");

@@ -1707,19 +1706,17 @@ static ssize_t trans_stat_show(struct device *dev,
 	len += sprintf(buf + len, "           :");
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				df->profile->freq_table[i]);
+				df->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (df->profile->freq_table[i]
-					== df->previous_freq) {
+		if (df->freq_table[i] == df->previous_freq)
 			len += sprintf(buf + len, "*");
-		} else {
+		else
 			len += sprintf(buf + len, " ");
-		}
-		len += sprintf(buf + len, "%10lu:",
-				df->profile->freq_table[i]);
+
+		len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
 				df->stats.trans_table[(i * max_state) + j]);

@@ -1743,7 +1740,7 @@ static ssize_t trans_stat_store(struct device *dev,
 	if (!df->profile)
 		return -EINVAL;
 
-	if (df->profile->max_state == 0)
+	if (df->max_state == 0)
 		return count;
 
 	err = kstrtoint(buf, 10, &value);

@@ -1751,11 +1748,11 @@ static ssize_t trans_stat_store(struct device *dev,
 		return -EINVAL;
 
 	mutex_lock(&df->lock);
-	memset(df->stats.time_in_state, 0, (df->profile->max_state *
+	memset(df->stats.time_in_state, 0, (df->max_state *
 					sizeof(*df->stats.time_in_state)));
 	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
-					df->profile->max_state,
-					df->profile->max_state));
+					df->max_state,
+					df->max_state));
 	df->stats.total_trans = 0;
 	df->stats.last_update = get_jiffies_64();
 	mutex_unlock(&df->lock);

drivers/devfreq/governor_passive.c +7 -7

index dcc9dd518197..1810966fd61d 100644
@@ -145,18 +145,18 @@ static int get_target_freq_with_devfreq(struct devfreq *devfreq,
 		goto out;
 
 	/* Use interpolation if required opps is not available */
-	for (i = 0; i < parent_devfreq->profile->max_state; i++)
-		if (parent_devfreq->profile->freq_table[i] == *freq)
+	for (i = 0; i < parent_devfreq->max_state; i++)
+		if (parent_devfreq->freq_table[i] == *freq)
 			break;
 
-	if (i == parent_devfreq->profile->max_state)
+	if (i == parent_devfreq->max_state)
 		return -EINVAL;
 
-	if (i < devfreq->profile->max_state) {
-		child_freq = devfreq->profile->freq_table[i];
+	if (i < devfreq->max_state) {
+		child_freq = devfreq->freq_table[i];
 	} else {
-		count = devfreq->profile->max_state;
-		child_freq = devfreq->profile->freq_table[count - 1];
+		count = devfreq->max_state;
+		child_freq = devfreq->freq_table[count - 1];
 	}
 
 out:

include/linux/devfreq.h +0 -0

index dc10bee75a72..770a7532655c 100644
@@ -185,6 +185,10 @@ struct devfreq {
 	struct notifier_block nb;
 	struct delayed_work work;
 

Quoted 1 line

include/linux/devfreq.h struct devfreq { · line 188

Quoted 1 line

include/linux/devfreq.h +1 -0

+	/* devfreq local freq_table */

Quoted 2 lines

include/linux/devfreq.h struct devfreq { · line 190

Quoted 2 lines

include/linux/devfreq.h +2 -0

+	unsigned long *freq_table;
+	unsigned int max_state;

Quoted 10 lines

Quoted 4 lines

include/linux/devfreq.h +1 -0

+
 	unsigned long previous_freq;
 	struct devfreq_dev_status last_status;
 

Signature · 3 lines

Best Regards,
Samsung Electronics
Chanwoo Choi

Don't print warning when a governor PROBE_DEFER as it's not a real GOV_START fail.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/devfreq/devfreq.c +0 -0

index 2e2b3b414d67..6a39638ed064 100644
@@ -931,8 +931,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,

Quoted 15 lines · Christian 'Ansuel' Marangi

Don't print warning when a governor PROBE_DEFER as it's not a real GOV_START fail.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/devfreq/devfreq.c +0 -0

index 2e2b3b414d67..6a39638ed064 100644
@@ -931,8 +931,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,

drivers/devfreq/devfreq.c struct devfreq *devfreq_add_device(struct device *dev, · line 939

Quoted 10 lines

drivers/devfreq/devfreq.c +3 -2

 						NULL);
 	if (err) {
-		dev_err(dev, "%s: Unable to start governor for the device\n",
-			__func__);
+		dev_err_probe(dev, err,
+			      "%s: Unable to start governor for the device\n",
+			      __func__);
 		goto err_init;
 	}
 	create_sysfs_files(devfreq, devfreq->governor);

In order to keep the left-align with above error log when try_then_request_governor() is failed,
I recommend to use the tab without space indentation as following:

If you have no objection, I'll merge this change.

drivers/devfreq/devfreq.c +3 -2

index 01474daf4548..80a1235ef8fb 100644
@@ -932,8 +932,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
        err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
                                                NULL);
        if (err) {
-               dev_err(dev, "%s: Unable to start governor for the device\n",
-                       __func__);
+               dev_err_probe(dev, err,
+                       "%s: Unable to start governor for the device\n",
+                        __func__);
                goto err_init;
        }
        create_sysfs_files(devfreq, devfreq->governor);

Signature · 4 lines

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi

Quoted 32 lines · Chanwoo Choi

Quoted 15 lines · Christian 'Ansuel' Marangi

Don't print warning when a governor PROBE_DEFER as it's not a real GOV_START fail.

Fixes a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")

Signed-off-by Christian 'Ansuel' Marangi <[email protected]>

---
 drivers/devfreq/devfreq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/devfreq/devfreq.c +0 -0

index 2e2b3b414d67..6a39638ed064 100644
@@ -931,8 +931,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,

drivers/devfreq/devfreq.c struct devfreq *devfreq_add_device(struct device *dev, · line 939

Quoted 10 lines

drivers/devfreq/devfreq.c +3 -2

 						NULL);
 	if (err) {
-		dev_err(dev, "%s: Unable to start governor for the device\n",
-			__func__);
+		dev_err_probe(dev, err,
+			      "%s: Unable to start governor for the device\n",
+			      __func__);
 		goto err_init;
 	}
 	create_sysfs_files(devfreq, devfreq->governor);

In order to keep the left-align with above error log when try_then_request_governor() is failed,
I recommend to use the tab without space indentation as following:

Quoted 2 lines

If you have no objection, I'll merge this change.

Sure, good for me. Anyway I wonder if we can relax the hard limit for 80 for error print since we now can use 100, but your choice.

Quoted 26 lines

drivers/devfreq/devfreq.c +3 -2

index 01474daf4548..80a1235ef8fb 100644
@@ -932,8 +932,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
        err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
                                                NULL);
        if (err) {
-               dev_err(dev, "%s: Unable to start governor for the device\n",
-                       __func__);
+               dev_err_probe(dev, err,
+                       "%s: Unable to start governor for the device\n",
+                        __func__);
                goto err_init;
        }
        create_sysfs_files(devfreq, devfreq->governor);

Signature · 4 lines

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi