CPUFreq: Cleanups/fixes for v3.13

---
 drivers/cpufreq/cpufreq.c | 38 +++++++++++---------------------------
 1 file changed, 11 insertions(+), 27 deletions(-)

drivers/cpufreq/cpufreq.c +11 ~~-27~~

index 04548f7..eb993d9 100644
@@ -67,13 +67,11 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
 
 #define lock_policy_rwsem(mode, cpu)					\
-static int lock_policy_rwsem_##mode(int cpu)				\
+static void lock_policy_rwsem_##mode(int cpu)				\
 {									\
 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
 	BUG_ON(!policy);						\
 	down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-									\
-	return 0;							\
 }
 
 lock_policy_rwsem(read, cpu);

@@ -653,13 +651,12 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 {
 	struct cpufreq_policy *policy = to_policy(kobj);
 	struct freq_attr *fattr = to_attr(attr);
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
 
 	if (!down_read_trylock(&cpufreq_rwsem))
-		goto exit;
+		return -EINVAL;
 
-	if (lock_policy_rwsem_read(policy->cpu) < 0)
-		goto up_read;
+	lock_policy_rwsem_read(policy->cpu);
 
 	if (fattr->show)
 		ret = fattr->show(policy, buf);

@@ -667,10 +664,8 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 		ret = -EIO;
 
 	unlock_policy_rwsem_read(policy->cpu);
-
-up_read:
 	up_read(&cpufreq_rwsem);
-exit:
+
 	return ret;
 }

@@ -689,8 +684,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 	if (!down_read_trylock(&cpufreq_rwsem))
 		goto unlock;
 
-	if (lock_policy_rwsem_write(policy->cpu) < 0)
-		goto up_read;
+	lock_policy_rwsem_write(policy->cpu);
 
 	if (fattr->store)
 		ret = fattr->store(policy, buf, count);

@@ -699,7 +693,6 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 
 	unlock_policy_rwsem_write(policy->cpu);
 
-up_read:
 	up_read(&cpufreq_rwsem);
 unlock:
 	put_online_cpus();

@@ -1147,7 +1140,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	if (ret) {
 		pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
-		WARN_ON(lock_policy_rwsem_write(old_cpu));
+		lock_policy_rwsem_write(old_cpu);
 		cpumask_set_cpu(old_cpu, policy->cpus);
 		unlock_policy_rwsem_write(old_cpu);

@@ -1243,7 +1236,7 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		return -EINVAL;
 	}
 
-	WARN_ON(lock_policy_rwsem_write(cpu));
+	lock_policy_rwsem_write(cpu);
 	cpus = cpumask_weight(policy->cpus);
 
 	if (cpus > 1)

@@ -1466,14 +1459,11 @@ unsigned int cpufreq_get(unsigned int cpu)
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return 0;
 
-	if (unlikely(lock_policy_rwsem_read(cpu)))
-		goto out_policy;
+	lock_policy_rwsem_read(cpu);
 
 	ret_freq = __cpufreq_get(cpu);
 
 	unlock_policy_rwsem_read(cpu);
-
-out_policy:
 	up_read(&cpufreq_rwsem);
 
 	return ret_freq;

@@ -1697,14 +1687,12 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int ret = -EINVAL;
 
-	if (unlikely(lock_policy_rwsem_write(policy->cpu)))
-		goto fail;
+	lock_policy_rwsem_write(policy->cpu);
 
 	ret = __cpufreq_driver_target(policy, target_freq, relation);
 
 	unlock_policy_rwsem_write(policy->cpu);
 
-fail:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cpufreq_driver_target);

@@ -1995,10 +1983,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		goto no_policy;
 	}
 
-	if (unlikely(lock_policy_rwsem_write(cpu))) {
-		ret = -EINVAL;
-		goto fail;
-	}
+	lock_policy_rwsem_write(cpu);
 
 	pr_debug("updating policy for CPU %u\n", cpu);
 	memcpy(&new_policy, policy, sizeof(*policy));

@@ -2027,7 +2012,6 @@ int cpufreq_update_policy(unsigned int cpu)
 
 	unlock_policy_rwsem_write(cpu);
 
-fail:
 	cpufreq_cpu_put(policy);
 no_policy:
 	return ret;

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 1/11

2013-10-03 07:09 UTC #2 lore raw

Re: [PATCH RESEND 01/11] cpufreq: make return type of lock_policy_rwsem_{read|write}() as void

Quoted 7 lines · Viresh Kumar

lock_policy_rwsem_{read|write}() currently has return type of int but it always return zero and hence its return type must be void instead. This patch makes its return type void and fixes all users of it as well.
Reported-by Jon Medhurst<[email protected]>
Signed-off-by Viresh Kumar <[email protected]>
---

Regards,
Srivatsa S. Bhat

Quoted 140 lines

 drivers/cpufreq/cpufreq.c | 38 +++++++++++---------------------------
 1 file changed, 11 insertions(+), 27 deletions(-)

drivers/cpufreq/cpufreq.c +11 ~~-27~~

index 04548f7..eb993d9 100644
@@ -67,13 +67,11 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
 
 #define lock_policy_rwsem(mode, cpu)					\
-static int lock_policy_rwsem_##mode(int cpu)				\
+static void lock_policy_rwsem_##mode(int cpu)				\
 {									\
 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
 	BUG_ON(!policy);						\
 	down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-									\
-	return 0;							\
 }
 
 lock_policy_rwsem(read, cpu);

@@ -653,13 +651,12 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 {
 	struct cpufreq_policy *policy = to_policy(kobj);
 	struct freq_attr *fattr = to_attr(attr);
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
 
 	if (!down_read_trylock(&cpufreq_rwsem))
-		goto exit;
+		return -EINVAL;
 
-	if (lock_policy_rwsem_read(policy->cpu) < 0)
-		goto up_read;
+	lock_policy_rwsem_read(policy->cpu);
 
 	if (fattr->show)
 		ret = fattr->show(policy, buf);

@@ -667,10 +664,8 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 		ret = -EIO;
 
 	unlock_policy_rwsem_read(policy->cpu);
-
-up_read:
 	up_read(&cpufreq_rwsem);
-exit:
+
 	return ret;
 }

@@ -689,8 +684,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 	if (!down_read_trylock(&cpufreq_rwsem))
 		goto unlock;
 
-	if (lock_policy_rwsem_write(policy->cpu) < 0)
-		goto up_read;
+	lock_policy_rwsem_write(policy->cpu);
 
 	if (fattr->store)
 		ret = fattr->store(policy, buf, count);

@@ -699,7 +693,6 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 
 	unlock_policy_rwsem_write(policy->cpu);
 
-up_read:
 	up_read(&cpufreq_rwsem);
 unlock:
 	put_online_cpus();

@@ -1147,7 +1140,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	if (ret) {
 		pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
-		WARN_ON(lock_policy_rwsem_write(old_cpu));
+		lock_policy_rwsem_write(old_cpu);
 		cpumask_set_cpu(old_cpu, policy->cpus);
 		unlock_policy_rwsem_write(old_cpu);

@@ -1243,7 +1236,7 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		return -EINVAL;
 	}
 
-	WARN_ON(lock_policy_rwsem_write(cpu));
+	lock_policy_rwsem_write(cpu);
 	cpus = cpumask_weight(policy->cpus);
 
 	if (cpus > 1)

@@ -1466,14 +1459,11 @@ unsigned int cpufreq_get(unsigned int cpu)
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return 0;
 
-	if (unlikely(lock_policy_rwsem_read(cpu)))
-		goto out_policy;
+	lock_policy_rwsem_read(cpu);
 
 	ret_freq = __cpufreq_get(cpu);
 
 	unlock_policy_rwsem_read(cpu);
-
-out_policy:
 	up_read(&cpufreq_rwsem);
 
 	return ret_freq;

@@ -1697,14 +1687,12 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int ret = -EINVAL;
 
-	if (unlikely(lock_policy_rwsem_write(policy->cpu)))
-		goto fail;
+	lock_policy_rwsem_write(policy->cpu);
 
 	ret = __cpufreq_driver_target(policy, target_freq, relation);
 
 	unlock_policy_rwsem_write(policy->cpu);
 
-fail:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cpufreq_driver_target);

@@ -1995,10 +1983,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		goto no_policy;
 	}
 
-	if (unlikely(lock_policy_rwsem_write(cpu))) {
-		ret = -EINVAL;
-		goto fail;
-	}
+	lock_policy_rwsem_write(cpu);
 
 	pr_debug("updating policy for CPU %u\n", cpu);
 	memcpy(&new_policy, policy, sizeof(*policy));

@@ -2027,7 +2012,6 @@ int cpufreq_update_policy(unsigned int cpu)
 
 	unlock_policy_rwsem_write(cpu);
 
-fail:
 	cpufreq_cpu_put(policy);
 no_policy:
 	return ret;

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #3 lore raw

PATCH RESEND 2/11 cpufreq: create per policy rwsem instead of per cpu cpu_policy_rwsem

We have per-cpu cpu_policy_rwsem for cpufreq core, but we never use all of them. We always use rwsem of policy->cpu and so we can actually make this rwsem per policy instead.

This patch does this change. With this change other tricky situations are also avoided now, like which lock to take while we are changing policy->cpu, etc.

---
 drivers/cpufreq/cpufreq.c | 110 +++++++++++++---------------------------------
 include/linux/cpufreq.h   |  14 ++++++
 2 files changed, 45 insertions(+), 79 deletions(-)

drivers/cpufreq/cpufreq.c +31 ~~-79~~

index eb993d9..ae866b1 100644
@@ -48,47 +48,6 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 #endif
 
 /*
- * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
- * all cpufreq/hotplug/workqueue/etc related lock issues.
- *
- * The rules for this semaphore:
- * - Any routine that wants to read from the policy structure will
- *   do a down_read on this semaphore.
- * - Any routine that will write to the policy structure and/or may take away
- *   the policy altogether (eg. CPU hotplug), will hold this lock in write
- *   mode before doing so.
- *
- * Additional rules:
- * - Governor routines that can be called in cpufreq hotplug path should not
- *   take this sem as top level hotplug notifier handler takes this.
- * - Lock should not be held across
- *     __cpufreq_governor(data, CPUFREQ_GOV_STOP);
- */
-static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
-
-#define lock_policy_rwsem(mode, cpu)					\
-static void lock_policy_rwsem_##mode(int cpu)				\
-{									\
-	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
-	BUG_ON(!policy);						\
-	down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-}
-
-lock_policy_rwsem(read, cpu);
-lock_policy_rwsem(write, cpu);
-
-#define unlock_policy_rwsem(mode, cpu)					\
-static void unlock_policy_rwsem_##mode(int cpu)				\
-{									\
-	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
-	BUG_ON(!policy);						\
-	up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-}
-
-unlock_policy_rwsem(read, cpu);
-unlock_policy_rwsem(write, cpu);
-
-/*
  * rwsem to guarantee that cpufreq driver module doesn't unload during critical
  * sections
  */

@@ -656,14 +615,14 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return -EINVAL;
 
-	lock_policy_rwsem_read(policy->cpu);
+	down_read(&policy->rwsem);
 
 	if (fattr->show)
 		ret = fattr->show(policy, buf);
 	else
 		ret = -EIO;
 
-	unlock_policy_rwsem_read(policy->cpu);
+	up_read(&policy->rwsem);
 	up_read(&cpufreq_rwsem);
 
 	return ret;

@@ -684,14 +643,14 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 	if (!down_read_trylock(&cpufreq_rwsem))
 		goto unlock;
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	if (fattr->store)
 		ret = fattr->store(policy, buf, count);
 	else
 		ret = -EIO;
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	up_read(&cpufreq_rwsem);
 unlock:

@@ -868,7 +827,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
 		}
 	}
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	write_lock_irqsave(&cpufreq_driver_lock, flags);

@@ -876,7 +835,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
 	per_cpu(cpufreq_cpu_data, cpu) = policy;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	if (has_target) {
 		if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||

@@ -923,6 +882,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(void)
 		goto err_free_cpumask;
 
 	INIT_LIST_HEAD(&policy->policy_list);
+	init_rwsem(&policy->rwsem);
+
 	return policy;
 
 err_free_cpumask:

@@ -945,19 +906,12 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
 	if (cpu == policy->cpu)
 		return;
 
-	/*
-	 * Take direct locks as lock_policy_rwsem_write wouldn't work here.
-	 * Also lock for last cpu is enough here as contention will happen only
-	 * after policy->cpu is changed and after it is changed, other threads
-	 * will try to acquire lock for new cpu. And policy is already updated
-	 * by then.
-	 */
-	down_write(&per_cpu(cpu_policy_rwsem, policy->cpu));
+	down_write(&policy->rwsem);
 
 	policy->last_cpu = policy->cpu;
 	policy->cpu = cpu;
 
-	up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu));
+	up_write(&policy->rwsem);
 
 #ifdef CONFIG_CPU_FREQ_TABLE
 	cpufreq_frequency_table_update_policy_cpu(policy);

@@ -1140,9 +1094,9 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	if (ret) {
 		pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
-		lock_policy_rwsem_write(old_cpu);
+		down_write(&policy->rwsem);
 		cpumask_set_cpu(old_cpu, policy->cpus);
-		unlock_policy_rwsem_write(old_cpu);
+		up_write(&policy->rwsem);
 
 		ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
 					"cpufreq");

@@ -1193,9 +1147,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 			policy->governor->name, CPUFREQ_NAME_LEN);
 #endif
 
-	lock_policy_rwsem_read(cpu);
+	down_read(&policy->rwsem);
 	cpus = cpumask_weight(policy->cpus);
-	unlock_policy_rwsem_read(cpu);
+	up_read(&policy->rwsem);
 
 	if (cpu != policy->cpu) {
 		if (!frozen)

@@ -1236,12 +1190,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		return -EINVAL;
 	}
 
-	lock_policy_rwsem_write(cpu);
+	down_write(&policy->rwsem);
 	cpus = cpumask_weight(policy->cpus);
 
 	if (cpus > 1)
 		cpumask_clear_cpu(cpu, policy->cpus);
-	unlock_policy_rwsem_write(cpu);
+	up_write(&policy->rwsem);
 
 	/* If cpu is last user of policy, free policy */
 	if (cpus == 1) {

@@ -1256,10 +1210,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		}
 
 		if (!frozen) {
-			lock_policy_rwsem_read(cpu);
+			down_read(&policy->rwsem);
 			kobj = &policy->kobj;
 			cmp = &policy->kobj_unregister;
-			unlock_policy_rwsem_read(cpu);
+			up_read(&policy->rwsem);
 			kobject_put(kobj);
 
 			/*

@@ -1451,19 +1405,22 @@ static unsigned int __cpufreq_get(unsigned int cpu)
  */
 unsigned int cpufreq_get(unsigned int cpu)
 {
+	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
 	unsigned int ret_freq = 0;
 
 	if (cpufreq_disabled() || !cpufreq_driver)
 		return -ENOENT;
 
+	BUG_ON(!policy);
+
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return 0;
 
-	lock_policy_rwsem_read(cpu);
+	down_read(&policy->rwsem);
 
 	ret_freq = __cpufreq_get(cpu);
 
-	unlock_policy_rwsem_read(cpu);
+	up_read(&policy->rwsem);
 	up_read(&cpufreq_rwsem);
 
 	return ret_freq;

@@ -1687,11 +1644,11 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int ret = -EINVAL;
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	ret = __cpufreq_driver_target(policy, target_freq, relation);
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	return ret;
 }

@@ -1922,10 +1879,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy,
 			/* end old governor */
 			if (policy->governor) {
 				__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
-				unlock_policy_rwsem_write(new_policy->cpu);
+				up_write(&new_policy->rwsem);
 				__cpufreq_governor(policy,
 						CPUFREQ_GOV_POLICY_EXIT);
-				lock_policy_rwsem_write(new_policy->cpu);
+				down_write(&new_policy->rwsem);
 			}
 
 			/* start new governor */

@@ -1934,10 +1891,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy,
 				if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
 					failed = 0;
 				} else {
-					unlock_policy_rwsem_write(new_policy->cpu);
+					up_write(&new_policy->rwsem);
 					__cpufreq_governor(policy,
 							CPUFREQ_GOV_POLICY_EXIT);
-					lock_policy_rwsem_write(new_policy->cpu);
+					down_write(&new_policy->rwsem);
 				}
 			}

@@ -1983,7 +1940,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		goto no_policy;
 	}
 
-	lock_policy_rwsem_write(cpu);
+	down_write(&policy->rwsem);
 
 	pr_debug("updating policy for CPU %u\n", cpu);
 	memcpy(&new_policy, policy, sizeof(*policy));

@@ -2010,7 +1967,7 @@ int cpufreq_update_policy(unsigned int cpu)
 
 	ret = __cpufreq_set_policy(policy, &new_policy);
 
-	unlock_policy_rwsem_write(cpu);
+	up_write(&policy->rwsem);
 
 	cpufreq_cpu_put(policy);
 no_policy:

@@ -2167,14 +2124,9 @@ EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
 
 static int __init cpufreq_core_init(void)
 {
-	int cpu;
-
 	if (cpufreq_disabled())
 		return -ENODEV;
 
-	for_each_possible_cpu(cpu)
-		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
-
 	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);

include/linux/cpufreq.h +14 -0

index 6b199ed..a72bac2 100644
@@ -85,6 +85,20 @@ struct cpufreq_policy {
 	struct list_head        policy_list;
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
+
+	/*
+	 * The rules for this semaphore:
+	 * - Any routine that wants to read from the policy structure will
+	 *   do a down_read on this semaphore.
+	 * - Any routine that will write to the policy structure and/or may take away
+	 *   the policy altogether (eg. CPU hotplug), will hold this lock in write
+	 *   mode before doing so.
+	 *
+	 * Additional rules:
+	 * - Lock should not be held across
+	 *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+	 */
+	struct rw_semaphore	rwsem;
 };
 
 /* Only for ACPI */

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 2/11

2013-10-03 07:23 UTC #4 lore raw

Re: [PATCH RESEND 02/11] cpufreq: create per policy rwsem instead of per cpu cpu_policy_rwsem

Quoted 10 lines · Viresh Kumar

We have per-cpu cpu_policy_rwsem for cpufreq core, but we never use all of them. We always use rwsem of policy->cpu and so we can actually make this rwsem per policy instead.
This patch does this change. With this change other tricky situations are also avoided now, like which lock to take while we are changing policy->cpu, etc.
Suggested-by Srivatsa S. Bhat <[email protected]>
Signed-off-by Viresh Kumar <[email protected]>
---

This is a very nice improvement!

Regards,
Srivatsa S. Bhat

Quoted 315 lines

 drivers/cpufreq/cpufreq.c | 110 +++++++++++++---------------------------------
 include/linux/cpufreq.h   |  14 ++++++
 2 files changed, 45 insertions(+), 79 deletions(-)

drivers/cpufreq/cpufreq.c +31 ~~-79~~

index eb993d9..ae866b1 100644
@@ -48,47 +48,6 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 #endif
 
 /*
- * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
- * all cpufreq/hotplug/workqueue/etc related lock issues.
- *
- * The rules for this semaphore:
- * - Any routine that wants to read from the policy structure will
- *   do a down_read on this semaphore.
- * - Any routine that will write to the policy structure and/or may take away
- *   the policy altogether (eg. CPU hotplug), will hold this lock in write
- *   mode before doing so.
- *
- * Additional rules:
- * - Governor routines that can be called in cpufreq hotplug path should not
- *   take this sem as top level hotplug notifier handler takes this.
- * - Lock should not be held across
- *     __cpufreq_governor(data, CPUFREQ_GOV_STOP);
- */
-static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
-
-#define lock_policy_rwsem(mode, cpu)					\
-static void lock_policy_rwsem_##mode(int cpu)				\
-{									\
-	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
-	BUG_ON(!policy);						\
-	down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-}
-
-lock_policy_rwsem(read, cpu);
-lock_policy_rwsem(write, cpu);
-
-#define unlock_policy_rwsem(mode, cpu)					\
-static void unlock_policy_rwsem_##mode(int cpu)				\
-{									\
-	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);	\
-	BUG_ON(!policy);						\
-	up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu));		\
-}
-
-unlock_policy_rwsem(read, cpu);
-unlock_policy_rwsem(write, cpu);
-
-/*
  * rwsem to guarantee that cpufreq driver module doesn't unload during critical
  * sections
  */

@@ -656,14 +615,14 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return -EINVAL;
 
-	lock_policy_rwsem_read(policy->cpu);
+	down_read(&policy->rwsem);
 
 	if (fattr->show)
 		ret = fattr->show(policy, buf);
 	else
 		ret = -EIO;
 
-	unlock_policy_rwsem_read(policy->cpu);
+	up_read(&policy->rwsem);
 	up_read(&cpufreq_rwsem);
 
 	return ret;

@@ -684,14 +643,14 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
 	if (!down_read_trylock(&cpufreq_rwsem))
 		goto unlock;
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	if (fattr->store)
 		ret = fattr->store(policy, buf, count);
 	else
 		ret = -EIO;
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	up_read(&cpufreq_rwsem);
 unlock:

@@ -868,7 +827,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
 		}
 	}
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	write_lock_irqsave(&cpufreq_driver_lock, flags);

@@ -876,7 +835,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
 	per_cpu(cpufreq_cpu_data, cpu) = policy;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	if (has_target) {
 		if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||

@@ -923,6 +882,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(void)
 		goto err_free_cpumask;
 
 	INIT_LIST_HEAD(&policy->policy_list);
+	init_rwsem(&policy->rwsem);
+
 	return policy;
 
 err_free_cpumask:

@@ -945,19 +906,12 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
 	if (cpu == policy->cpu)
 		return;
 
-	/*
-	 * Take direct locks as lock_policy_rwsem_write wouldn't work here.
-	 * Also lock for last cpu is enough here as contention will happen only
-	 * after policy->cpu is changed and after it is changed, other threads
-	 * will try to acquire lock for new cpu. And policy is already updated
-	 * by then.
-	 */
-	down_write(&per_cpu(cpu_policy_rwsem, policy->cpu));
+	down_write(&policy->rwsem);
 
 	policy->last_cpu = policy->cpu;
 	policy->cpu = cpu;
 
-	up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu));
+	up_write(&policy->rwsem);
 
 #ifdef CONFIG_CPU_FREQ_TABLE
 	cpufreq_frequency_table_update_policy_cpu(policy);

@@ -1140,9 +1094,9 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	if (ret) {
 		pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
-		lock_policy_rwsem_write(old_cpu);
+		down_write(&policy->rwsem);
 		cpumask_set_cpu(old_cpu, policy->cpus);
-		unlock_policy_rwsem_write(old_cpu);
+		up_write(&policy->rwsem);
 
 		ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
 					"cpufreq");

@@ -1193,9 +1147,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 			policy->governor->name, CPUFREQ_NAME_LEN);
 #endif
 
-	lock_policy_rwsem_read(cpu);
+	down_read(&policy->rwsem);
 	cpus = cpumask_weight(policy->cpus);
-	unlock_policy_rwsem_read(cpu);
+	up_read(&policy->rwsem);
 
 	if (cpu != policy->cpu) {
 		if (!frozen)

@@ -1236,12 +1190,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		return -EINVAL;
 	}
 
-	lock_policy_rwsem_write(cpu);
+	down_write(&policy->rwsem);
 	cpus = cpumask_weight(policy->cpus);
 
 	if (cpus > 1)
 		cpumask_clear_cpu(cpu, policy->cpus);
-	unlock_policy_rwsem_write(cpu);
+	up_write(&policy->rwsem);
 
 	/* If cpu is last user of policy, free policy */
 	if (cpus == 1) {

@@ -1256,10 +1210,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		}
 
 		if (!frozen) {
-			lock_policy_rwsem_read(cpu);
+			down_read(&policy->rwsem);
 			kobj = &policy->kobj;
 			cmp = &policy->kobj_unregister;
-			unlock_policy_rwsem_read(cpu);
+			up_read(&policy->rwsem);
 			kobject_put(kobj);
 
 			/*

@@ -1451,19 +1405,22 @@ static unsigned int __cpufreq_get(unsigned int cpu)
  */
 unsigned int cpufreq_get(unsigned int cpu)
 {
+	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
 	unsigned int ret_freq = 0;
 
 	if (cpufreq_disabled() || !cpufreq_driver)
 		return -ENOENT;
 
+	BUG_ON(!policy);
+
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return 0;
 
-	lock_policy_rwsem_read(cpu);
+	down_read(&policy->rwsem);
 
 	ret_freq = __cpufreq_get(cpu);
 
-	unlock_policy_rwsem_read(cpu);
+	up_read(&policy->rwsem);
 	up_read(&cpufreq_rwsem);
 
 	return ret_freq;

@@ -1687,11 +1644,11 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int ret = -EINVAL;
 
-	lock_policy_rwsem_write(policy->cpu);
+	down_write(&policy->rwsem);
 
 	ret = __cpufreq_driver_target(policy, target_freq, relation);
 
-	unlock_policy_rwsem_write(policy->cpu);
+	up_write(&policy->rwsem);
 
 	return ret;
 }

@@ -1922,10 +1879,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy,
 			/* end old governor */
 			if (policy->governor) {
 				__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
-				unlock_policy_rwsem_write(new_policy->cpu);
+				up_write(&new_policy->rwsem);
 				__cpufreq_governor(policy,
 						CPUFREQ_GOV_POLICY_EXIT);
-				lock_policy_rwsem_write(new_policy->cpu);
+				down_write(&new_policy->rwsem);
 			}
 
 			/* start new governor */

@@ -1934,10 +1891,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy,
 				if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
 					failed = 0;
 				} else {
-					unlock_policy_rwsem_write(new_policy->cpu);
+					up_write(&new_policy->rwsem);
 					__cpufreq_governor(policy,
 							CPUFREQ_GOV_POLICY_EXIT);
-					lock_policy_rwsem_write(new_policy->cpu);
+					down_write(&new_policy->rwsem);
 				}
 			}

@@ -1983,7 +1940,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		goto no_policy;
 	}
 
-	lock_policy_rwsem_write(cpu);
+	down_write(&policy->rwsem);
 
 	pr_debug("updating policy for CPU %u\n", cpu);
 	memcpy(&new_policy, policy, sizeof(*policy));

@@ -2010,7 +1967,7 @@ int cpufreq_update_policy(unsigned int cpu)
 
 	ret = __cpufreq_set_policy(policy, &new_policy);
 
-	unlock_policy_rwsem_write(cpu);
+	up_write(&policy->rwsem);
 
 	cpufreq_cpu_put(policy);
 no_policy:

@@ -2167,14 +2124,9 @@ EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
 
 static int __init cpufreq_core_init(void)
 {
-	int cpu;
-
 	if (cpufreq_disabled())
 		return -ENODEV;
 
-	for_each_possible_cpu(cpu)
-		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
-
 	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);

include/linux/cpufreq.h +14 -0

index 6b199ed..a72bac2 100644
@@ -85,6 +85,20 @@ struct cpufreq_policy {
 	struct list_head        policy_list;
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
+
+	/*
+	 * The rules for this semaphore:
+	 * - Any routine that wants to read from the policy structure will
+	 *   do a down_read on this semaphore.
+	 * - Any routine that will write to the policy structure and/or may take away
+	 *   the policy altogether (eg. CPU hotplug), will hold this lock in write
+	 *   mode before doing so.
+	 *
+	 * Additional rules:
+	 * - Lock should not be held across
+	 *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+	 */
+	struct rw_semaphore	rwsem;
 };
 
 /* Only for ACPI */

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #5 lore raw

PATCH RESEND 3/11 cpufreq: remove invalid comment from __cpufreq_remove_dev()

Some section of kerneldoc comment for __cpufreq_remove_dev() is invalid now. Remove it.

---
 drivers/cpufreq/cpufreq.c | 2 --
 1 file changed, 2 deletions(-)

drivers/cpufreq/cpufreq.c +0 -2

index ae866b1..d80cbe6 100644
@@ -1260,8 +1260,6 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
  * __cpufreq_remove_dev - remove a CPU device
  *
  * Removes the cpufreq interface for a CPU device.
- * Caller should already have policy_rwsem in write mode for this CPU.
- * This routine frees the rwsem before returning.
  */
 static inline int __cpufreq_remove_dev(struct device *dev,
 				       struct subsys_interface *sif,

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 3/11

2013-10-03 07:25 UTC #6 lore raw

Re: [PATCH RESEND 03/11] cpufreq: remove invalid comment from __cpufreq_remove_dev()

Quoted 5 lines · Viresh Kumar

Some section of kerneldoc comment for __cpufreq_remove_dev() is invalid now. Remove it.
Suggested-by Srivatsa S. Bhat <[email protected]>
Signed-off-by Viresh Kumar <[email protected]>

Regards,
Srivatsa S. Bhat

Quoted 18 lines

---
 drivers/cpufreq/cpufreq.c | 2 --
 1 file changed, 2 deletions(-)

drivers/cpufreq/cpufreq.c +0 -2

index ae866b1..d80cbe6 100644
@@ -1260,8 +1260,6 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
  * __cpufreq_remove_dev - remove a CPU device
  *
  * Removes the cpufreq interface for a CPU device.
- * Caller should already have policy_rwsem in write mode for this CPU.
- * This routine frees the rwsem before returning.
  */
 static inline int __cpufreq_remove_dev(struct device *dev,
 				       struct subsys_interface *sif,

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #7 lore raw

PATCH RESEND 4/11 cpufreq: Remove extra blank line

We don't need a blank line just at start of a block, lets remove it.

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

drivers/cpufreq/cpufreq.c +0 -1

index d80cbe6..d149caa 100644
@@ -1155,7 +1155,6 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 		if (!frozen)
 			sysfs_remove_link(&dev->kobj, "cpufreq");
 	} else if (cpus > 1) {
-
 		new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
 		if (new_cpu >= 0) {
 			update_policy_cpu(policy, new_cpu);

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 4/11

2013-10-03 07:26 UTC #8 lore raw

Re: [PATCH RESEND 04/11] cpufreq: Remove extra blank line

Quoted 3 lines · Viresh Kumar

We don't need a blank line just at start of a block, lets remove it.
Signed-off-by Viresh Kumar <[email protected]>

Regards,
Srivatsa S. Bhat

Quoted 17 lines

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

drivers/cpufreq/cpufreq.c +0 -1

index d80cbe6..d149caa 100644
@@ -1155,7 +1155,6 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 		if (!frozen)
 			sysfs_remove_link(&dev->kobj, "cpufreq");
 	} else if (cpus > 1) {
-
 		new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
 		if (new_cpu >= 0) {
 			update_policy_cpu(policy, new_cpu);

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #9 lore raw

PATCH RESEND 5/11 cpufreq: don't break string in print statements

As a rule its better not to break string (quoted inside "") in a print statement even if it crosses 80 column boundary as that may introduce unwanted bugs and so this patch rewrites one of the print statements..

---
 drivers/cpufreq/cpufreq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/cpufreq/cpufreq.c +2 -2

index d149caa..065b4dd 100644
@@ -1160,8 +1160,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 			update_policy_cpu(policy, new_cpu);
 
 			if (!frozen) {
-				pr_debug("%s: policy Kobject moved to cpu: %d "
-					 "from: %d\n",__func__, new_cpu, cpu);
+				pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
+						__func__, new_cpu, cpu);
 			}
 		}
 	}

Signature · 1 line

1.7.12.rc2.18.g61b472e

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #10 lore raw

PATCH RESEND 6/11 cpufreq: remove __cpufreq_remove_dev()

Nobody except cpufreq_remove_dev() is calling __cpufreq_remove_dev() and so we don't need separate routines here. Lets merge code from __cpufreq_remove_dev() to cpufreq_remove_dev() and get rid of __cpufreq_remove_dev().

---
 drivers/cpufreq/cpufreq.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

drivers/cpufreq/cpufreq.c +8 ~~-18~~

index 065b4dd..1394dac 100644
@@ -1256,34 +1256,24 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 }
 
 /**
- * __cpufreq_remove_dev - remove a CPU device
+ * cpufreq_remove_dev - remove a CPU device
  *
  * Removes the cpufreq interface for a CPU device.
  */
-static inline int __cpufreq_remove_dev(struct device *dev,
-				       struct subsys_interface *sif,
-				       bool frozen)
-{
-	int ret;
-
-	ret = __cpufreq_remove_dev_prepare(dev, sif, frozen);
-
-	if (!ret)
-		ret = __cpufreq_remove_dev_finish(dev, sif, frozen);
-
-	return ret;
-}
-
 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
-	int retval;
+	int ret;
 
 	if (cpu_is_offline(cpu))
 		return 0;
 
-	retval = __cpufreq_remove_dev(dev, sif, false);
-	return retval;
+	ret = __cpufreq_remove_dev_prepare(dev, sif, false);
+
+	if (!ret)
+		ret = __cpufreq_remove_dev_finish(dev, sif, false);
+
+	return ret;
 }
 
 static void handle_update(struct work_struct *work)

Signature · 1 line

1.7.12.rc2.18.g61b472e

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #11 lore raw

PATCH RESEND 7/11 cpufreq: Optimize cpufreq_frequency_table_verify()

cpufreq_frequency_table_verify() is a bit rewritten here to make it more logical and optimal.
- merge multiple lines for variable declarations together.
- quit early if any frequency between min/max is found.
- don't call cpufreq_verify_within_limits() in case any valid freq is found as it is of no use.
- count renamed as found and made a boolean.

---
 drivers/cpufreq/freq_table.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

drivers/cpufreq/freq_table.c +13 ~~-12~~

index 11f6fa9..10f3cfb 100644
@@ -54,9 +54,8 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 				   struct cpufreq_frequency_table *table)
 {
-	unsigned int next_larger = ~0;
-	unsigned int i;
-	unsigned int count = 0;
+	unsigned int next_larger = ~0, freq, i = 0;
+	bool found = false;
 
 	pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
 					policy->min, policy->max, policy->cpu);

@@ -64,21 +63,23 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 				     policy->cpuinfo.max_freq);
 
-	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
-		unsigned int freq = table[i].frequency;
+	for (; freq = table[i].frequency, freq != CPUFREQ_TABLE_END; i++) {
 		if (freq == CPUFREQ_ENTRY_INVALID)
 			continue;
-		if ((freq >= policy->min) && (freq <= policy->max))
-			count++;
-		else if ((next_larger > freq) && (freq > policy->max))
+		if ((freq >= policy->min) && (freq <= policy->max)) {
+			found = true;
+			break;
+		}
+
+		if ((next_larger > freq) && (freq > policy->max))
 			next_larger = freq;
 	}
 
-	if (!count)
+	if (!found) {
 		policy->max = next_larger;
-
-	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
-				     policy->cpuinfo.max_freq);
+		cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+				policy->cpuinfo.max_freq);
+	}
 
 	pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
 				policy->min, policy->max, policy->cpu);

Signature · 1 line

1.7.12.rc2.18.g61b472e

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #12 lore raw

PATCH RESEND 8/11 cpufreq: rename __cpufreq_set_policy() as cpufreq_set_policy()

Earlier there used to be two functions named __cpufreq_set_policy() and cpufreq_set_policy(), but now we only have a single routine lets name it cpufreq_set_policy() instead of __cpufreq_set_policy().

This also removes some invalid comments or fixes some incorrect comments.

---
 drivers/cpufreq/cpufreq.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

drivers/cpufreq/cpufreq.c +9 ~~-13~~

index 1394dac..267ae99 100644
@@ -371,7 +371,7 @@ show_one(scaling_min_freq, min);
 show_one(scaling_max_freq, max);
 show_one(scaling_cur_freq, cur);
 
-static int __cpufreq_set_policy(struct cpufreq_policy *policy,
+static int cpufreq_set_policy(struct cpufreq_policy *policy,
 				struct cpufreq_policy *new_policy);
 
 /**

@@ -392,7 +392,7 @@ static ssize_t store_##file_name					\
 	if (ret != 1)							\
 		return -EINVAL;						\
 									\
-	ret = __cpufreq_set_policy(policy, &new_policy);		\
+	ret = cpufreq_set_policy(policy, &new_policy);		\
 	policy->user_policy.object = policy->object;			\
 									\
 	return ret ? ret : count;					\

@@ -450,11 +450,7 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 						&new_policy.governor))
 		return -EINVAL;
 
-	/*
-	 * Do not use cpufreq_set_policy here or the user_policy.max
-	 * will be wrongly overridden
-	 */
-	ret = __cpufreq_set_policy(policy, &new_policy);
+	ret = cpufreq_set_policy(policy, &new_policy);
 
 	policy->user_policy.policy = policy->policy;
 	policy->user_policy.governor = policy->governor;

@@ -796,11 +792,11 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy)
 	int ret = 0;
 
 	memcpy(&new_policy, policy, sizeof(*policy));
-	/* assure that the starting sequence is run in __cpufreq_set_policy */
+	/* assure that the starting sequence is run in cpufreq_set_policy */
 	policy->governor = NULL;
 
 	/* set default policy */
-	ret = __cpufreq_set_policy(policy, &new_policy);
+	ret = cpufreq_set_policy(policy, &new_policy);
 	policy->user_policy.policy = policy->policy;
 	policy->user_policy.governor = policy->governor;

@@ -1803,10 +1799,10 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
 EXPORT_SYMBOL(cpufreq_get_policy);
 
 /*
- * data   : current policy.
- * policy : policy to be set.
+ * policy : current policy.
+ * new_policy: policy to be set.
  */
-static int __cpufreq_set_policy(struct cpufreq_policy *policy,
+static int cpufreq_set_policy(struct cpufreq_policy *policy,
 				struct cpufreq_policy *new_policy)
 {
 	int ret = 0, failed = 1;

@@ -1952,7 +1948,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		}
 	}
 
-	ret = __cpufreq_set_policy(policy, &new_policy);
+	ret = cpufreq_set_policy(policy, &new_policy);
 
 	up_write(&policy->rwsem);

Signature · 1 line

1.7.12.rc2.18.g61b472e

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #13 lore raw

PATCH RESEND 9/11 cpufreq: rewrite cpufreq_driver->flags using shift operator

Currently cpufreq_driver's flags are defined directly using 0x1, 0x2, 0x4, 0x8, etc.. As the list grows it doesn't stays much readable..

Lets use bitwise shift operator << to generate these numbers for respective positions.

---
 include/linux/cpufreq.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

include/linux/cpufreq.h +8 -7

index a72bac2..9321059 100644
@@ -225,13 +225,14 @@ struct cpufreq_driver {
 };
 
 /* flags */
-#define CPUFREQ_STICKY		0x01	/* the driver isn't removed even if
-					 * all ->init() calls failed */
-#define CPUFREQ_CONST_LOOPS	0x02	/* loops_per_jiffy or other kernel
-					 * "constants" aren't affected by
-					 * frequency transitions */
-#define CPUFREQ_PM_NO_WARN	0x04	/* don't warn on suspend/resume speed
-					 * mismatches */
+#define CPUFREQ_STICKY		(1 << 0)	/* driver isn't removed even if
+						   all ->init() calls failed */
+#define CPUFREQ_CONST_LOOPS	(1 << 1)	/* loops_per_jiffy or other
+						   kernel "constants" aren't
+						   affected by frequency
+						   transitions */
+#define CPUFREQ_PM_NO_WARN	(1 << 2)	/* don't warn on suspend/resume
+						   speed mismatches */
 
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 9/11

2013-10-03 07:32 UTC #14 lore raw

Re: [PATCH RESEND 09/11] cpufreq: rewrite cpufreq_driver->flags using shift operator

Quoted 8 lines · Viresh Kumar

Currently cpufreq_driver's flags are defined directly using 0x1, 0x2, 0x4, 0x8, etc.. As the list grows it doesn't stays much readable..
Lets use bitwise shift operator << to generate these numbers for respective positions.
Signed-off-by Viresh Kumar <[email protected]>
---

Regards,
Srivatsa S. Bhat

Quoted 30 lines

 include/linux/cpufreq.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

include/linux/cpufreq.h +8 -7

index a72bac2..9321059 100644
@@ -225,13 +225,14 @@ struct cpufreq_driver {
 };
 
 /* flags */
-#define CPUFREQ_STICKY		0x01	/* the driver isn't removed even if
-					 * all ->init() calls failed */
-#define CPUFREQ_CONST_LOOPS	0x02	/* loops_per_jiffy or other kernel
-					 * "constants" aren't affected by
-					 * frequency transitions */
-#define CPUFREQ_PM_NO_WARN	0x04	/* don't warn on suspend/resume speed
-					 * mismatches */
+#define CPUFREQ_STICKY		(1 << 0)	/* driver isn't removed even if
+						   all ->init() calls failed */
+#define CPUFREQ_CONST_LOOPS	(1 << 1)	/* loops_per_jiffy or other
+						   kernel "constants" aren't
+						   affected by frequency
+						   transitions */
+#define CPUFREQ_PM_NO_WARN	(1 << 2)	/* don't warn on suspend/resume
+						   speed mismatches */
 
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #15 lore raw

PATCH RESEND 10/11 cpufreq: use cpufreq_driver->flags to mark CPUFREQ_HAVE_GOVERNOR_PER_POLICY

Lets use cpufreq_driver->flags to mark CPUFREQ_HAVE_GOVERNOR_PER_POLICY instead of a separate field within cpufreq_driver. This will save some bytes for us.

---
 drivers/cpufreq/arm_big_little.c   |  4 ++--
 drivers/cpufreq/cpufreq.c          |  2 +-
 drivers/cpufreq/cpufreq_governor.h |  5 ++++-
 include/linux/cpufreq.h            | 15 ++++++++-------
 4 files changed, 15 insertions(+), 11 deletions(-)

drivers/cpufreq/arm_big_little.c +2 -2

index 9acfb82..2c7c134 100644
@@ -213,13 +213,13 @@ static struct freq_attr *bL_cpufreq_attr[] = {
 
 static struct cpufreq_driver bL_cpufreq_driver = {
 	.name			= "arm-big-little",
-	.flags			= CPUFREQ_STICKY,
+	.flags			= CPUFREQ_STICKY |
+					CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 	.verify			= bL_cpufreq_verify_policy,
 	.target			= bL_cpufreq_set_target,
 	.get			= bL_cpufreq_get,
 	.init			= bL_cpufreq_init,
 	.exit			= bL_cpufreq_exit,
-	.have_governor_per_policy = true,
 	.attr			= bL_cpufreq_attr,
 };

drivers/cpufreq/cpufreq.c +1 -1

index 267ae99..23e0a40 100644
@@ -92,7 +92,7 @@ static DEFINE_MUTEX(cpufreq_governor_mutex);
 
 bool have_governor_per_policy(void)
 {
-	return cpufreq_driver->have_governor_per_policy;
+	return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
 }
 EXPORT_SYMBOL_GPL(have_governor_per_policy);

drivers/cpufreq/cpufreq_governor.h +4 -1

index 88cd39f..b5f2b86 100644
@@ -191,7 +191,10 @@ struct common_dbs_data {
 	struct attribute_group *attr_group_gov_sys; /* one governor - system */
 	struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 
-	/* Common data for platforms that don't set have_governor_per_policy */
+	/*
+	 * Common data for platforms that don't set
+	 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
+	 */
 	struct dbs_data *gdbs_data;
 
 	struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);

include/linux/cpufreq.h +8 -7

index 9321059..6c9c365 100644
@@ -194,13 +194,6 @@ __ATTR(_name, 0644, show_##_name, store_##_name)
 struct cpufreq_driver {
 	char			name[CPUFREQ_NAME_LEN];
 	u8			flags;
-	/*
-	 * This should be set by platforms having multiple clock-domains, i.e.
-	 * supporting multiple policies. With this sysfs directories of governor
-	 * would be created in cpu/cpu<num>/cpufreq/ directory and so they can
-	 * use the same governor with different tunables for different clusters.
-	 */
-	bool			have_governor_per_policy;
 
 	/* needed by all drivers */
 	int	(*init)		(struct cpufreq_policy *policy);

@@ -234,6 +227,14 @@ struct cpufreq_driver {
 #define CPUFREQ_PM_NO_WARN	(1 << 2)	/* don't warn on suspend/resume
 						   speed mismatches */
 
+/*
+ * This should be set by platforms having multiple clock-domains, i.e.
+ * supporting multiple policies. With this sysfs directories of governor would
+ * be created in cpu/cpu<num>/cpufreq/ directory and so they can use the same
+ * governor with different tunables for different clusters.
+ */
+#define CPUFREQ_HAVE_GOVERNOR_PER_POLICY (1 << 3)
+
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);

Signature · 1 line

1.7.12.rc2.18.g61b472e

Srivatsa S. Bhat

Reviewed-by on v1 10/11

2013-10-03 07:39 UTC #16 lore raw

Re: [PATCH RESEND 10/11] cpufreq: use cpufreq_driver->flags to mark CPUFREQ_HAVE_GOVERNOR_PER_POLICY

Quoted 5 lines · Viresh Kumar

Lets use cpufreq_driver->flags to mark CPUFREQ_HAVE_GOVERNOR_PER_POLICY instead of a separate field within cpufreq_driver. This will save some bytes for us.
Signed-off-by Viresh Kumar <[email protected]>
---

Regards,
Srivatsa S. Bhat

Quoted 88 lines

 drivers/cpufreq/arm_big_little.c   |  4 ++--
 drivers/cpufreq/cpufreq.c          |  2 +-
 drivers/cpufreq/cpufreq_governor.h |  5 ++++-
 include/linux/cpufreq.h            | 15 ++++++++-------
 4 files changed, 15 insertions(+), 11 deletions(-)

drivers/cpufreq/arm_big_little.c +2 -2

index 9acfb82..2c7c134 100644
@@ -213,13 +213,13 @@ static struct freq_attr *bL_cpufreq_attr[] = {
 
 static struct cpufreq_driver bL_cpufreq_driver = {
 	.name			= "arm-big-little",
-	.flags			= CPUFREQ_STICKY,
+	.flags			= CPUFREQ_STICKY |
+					CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 	.verify			= bL_cpufreq_verify_policy,
 	.target			= bL_cpufreq_set_target,
 	.get			= bL_cpufreq_get,
 	.init			= bL_cpufreq_init,
 	.exit			= bL_cpufreq_exit,
-	.have_governor_per_policy = true,
 	.attr			= bL_cpufreq_attr,
 };

drivers/cpufreq/cpufreq.c +1 -1

index 267ae99..23e0a40 100644
@@ -92,7 +92,7 @@ static DEFINE_MUTEX(cpufreq_governor_mutex);
 
 bool have_governor_per_policy(void)
 {
-	return cpufreq_driver->have_governor_per_policy;
+	return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
 }
 EXPORT_SYMBOL_GPL(have_governor_per_policy);

drivers/cpufreq/cpufreq_governor.h +4 -1

index 88cd39f..b5f2b86 100644
@@ -191,7 +191,10 @@ struct common_dbs_data {
 	struct attribute_group *attr_group_gov_sys; /* one governor - system */
 	struct attribute_group *attr_group_gov_pol; /* one governor - policy */
 
-	/* Common data for platforms that don't set have_governor_per_policy */
+	/*
+	 * Common data for platforms that don't set
+	 * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
+	 */
 	struct dbs_data *gdbs_data;
 
 	struct cpu_dbs_common_info *(*get_cpu_cdbs)(int cpu);

include/linux/cpufreq.h +8 -7

index 9321059..6c9c365 100644
@@ -194,13 +194,6 @@ __ATTR(_name, 0644, show_##_name, store_##_name)
 struct cpufreq_driver {
 	char			name[CPUFREQ_NAME_LEN];
 	u8			flags;
-	/*
-	 * This should be set by platforms having multiple clock-domains, i.e.
-	 * supporting multiple policies. With this sysfs directories of governor
-	 * would be created in cpu/cpu<num>/cpufreq/ directory and so they can
-	 * use the same governor with different tunables for different clusters.
-	 */
-	bool			have_governor_per_policy;
 
 	/* needed by all drivers */
 	int	(*init)		(struct cpufreq_policy *policy);

@@ -234,6 +227,14 @@ struct cpufreq_driver {
 #define CPUFREQ_PM_NO_WARN	(1 << 2)	/* don't warn on suspend/resume
 						   speed mismatches */
 
+/*
+ * This should be set by platforms having multiple clock-domains, i.e.
+ * supporting multiple policies. With this sysfs directories of governor would
+ * be created in cpu/cpu<num>/cpufreq/ directory and so they can use the same
+ * governor with different tunables for different clusters.
+ */
+#define CPUFREQ_HAVE_GOVERNOR_PER_POLICY (1 << 3)
+
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);

Viresh Kumar

author maintainer

2013-10-02 08:43 UTC #17 lore raw

PATCH RESEND 11/11 cpufreq: add new routine cpufreq_verify_within_cpu_limits()

Most of the users of cpufreq_verify_within_limits() calls it for limiting with min/max from policy->cpuinfo. We can make that code simple by introducing another routine which will do this for them automatically.

This patch adds another routine cpufreq_verify_within_cpu_limits() and updates others to use it.