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Date: Mon, 27 Jul 2015 16:09:44 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM list <linux-pm@...r.kernel.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Russell King - ARM Linux <linux@....linux.org.uk>
Subject: [PATCH 7/7] cpufreq: Separate CPU device removal from CPU online
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
To separate the CPU online interface from the CPU device removal
one, split cpufreq_online() out of cpufreq_add_dev() and make
cpufreq_cpu_callback() call the former, while the latter will only
be used as the CPU device removal subsystem interface callback.
While at it, notice that the return value of sif->add_dev() is
ignored in bus_probe_device(), so (the new) cpufreq_add_dev()
doesn't need to bother with returning anything different from 0
and cpufreq_online() may be a void function.
Moreover, since the return value of cpufreq_add_policy_cpu() is
going to be ignored now too, make a void function of it as well.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Suggested-by: Russell King <linux@....linux.org.uk>
---
drivers/cpufreq/cpufreq.c | 125 ++++++++++++++++++++++------------------------
1 file changed, 61 insertions(+), 64 deletions(-)
Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -1056,19 +1056,17 @@ static int cpufreq_init_policy(struct cp
return cpufreq_set_policy(policy, &new_policy);
}
-static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
+static void cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
{
- int ret = 0;
-
/* Has this CPU been taken care of already? */
if (cpumask_test_cpu(cpu, policy->cpus))
- return 0;
+ return;
if (has_target()) {
- ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
if (ret) {
pr_err("%s: Failed to stop governor\n", __func__);
- return ret;
+ return;
}
}
@@ -1077,17 +1075,13 @@ static int cpufreq_add_policy_cpu(struct
up_write(&policy->rwsem);
if (has_target()) {
- ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
if (!ret)
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
- if (ret) {
+ if (ret)
pr_err("%s: Failed to start governor\n", __func__);
- return ret;
- }
}
-
- return 0;
}
static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
@@ -1191,44 +1185,24 @@ static void cpufreq_policy_free(struct c
kfree(policy);
}
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
- */
-static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+static void cpufreq_online(unsigned int cpu)
{
- unsigned int j, cpu = dev->id;
- int ret = -ENOMEM;
struct cpufreq_policy *policy;
- unsigned long flags;
bool recover_policy;
+ unsigned long flags;
+ unsigned int j;
+ int ret;
- pr_debug("adding CPU %u\n", cpu);
-
- if (cpu_is_offline(cpu)) {
- /*
- * Only possible if we are here from the subsys_interface add
- * callback. A hotplug notifier will follow and we will handle
- * it as CPU online then. For now, just create the sysfs link,
- * unless there is no policy or the link is already present.
- */
- policy = per_cpu(cpufreq_cpu_data, cpu);
- return policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
- ? add_cpu_dev_symlink(policy, cpu) : 0;
- }
+ pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
/* Check if this CPU already has a policy to manage it */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy) {
WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
- if (!policy_is_inactive(policy))
- return cpufreq_add_policy_cpu(policy, cpu);
-
+ if (!policy_is_inactive(policy)) {
+ cpufreq_add_policy_cpu(policy, cpu);
+ return;
+ }
/* This is the only online CPU for the policy. Start over. */
recover_policy = true;
down_write(&policy->rwsem);
@@ -1239,7 +1213,7 @@ static int cpufreq_add_dev(struct device
recover_policy = false;
policy = cpufreq_policy_alloc(cpu);
if (!policy)
- return -ENOMEM;
+ return;
}
cpumask_copy(policy->cpus, cpumask_of(cpu));
@@ -1362,7 +1336,7 @@ static int cpufreq_add_dev(struct device
pr_debug("initialization complete\n");
- return 0;
+ return;
out_remove_policy_notify:
/* cpufreq_policy_free() will notify based on this */
@@ -1374,7 +1348,34 @@ out_exit_policy:
cpufreq_driver->exit(policy);
out_free_policy:
cpufreq_policy_free(policy, recover_policy);
- return ret;
+}
+
+/**
+ * cpufreq_add_dev - the cpufreq interface for a CPU device.
+ * @dev: CPU device.
+ * @sif: Subsystem interface structure pointer (not used)
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+ unsigned cpu = dev->id;
+
+ dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
+
+ if (cpu_online(cpu)) {
+ cpufreq_online(cpu);
+ } else {
+ /*
+ * A hotplug notifier will follow and we will handle it as CPU
+ * online then. For now, just create the sysfs link, unless
+ * there is no policy or the link is already present.
+ */
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
+
+ if (policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus))
+ WARN_ON(add_cpu_dev_symlink(policy, cpu));
+ }
+
+ return 0;
}
static void cpufreq_offline_prepare(unsigned int cpu)
@@ -2340,27 +2341,23 @@ static int cpufreq_cpu_callback(struct n
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
- struct device *dev;
- dev = get_cpu_device(cpu);
- if (dev) {
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_ONLINE:
- cpufreq_add_dev(dev, NULL);
- break;
-
- case CPU_DOWN_PREPARE:
- cpufreq_offline_prepare(cpu);
- break;
-
- case CPU_POST_DEAD:
- cpufreq_offline_finish(cpu);
- break;
-
- case CPU_DOWN_FAILED:
- cpufreq_add_dev(dev, NULL);
- break;
- }
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ cpufreq_online(cpu);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ cpufreq_offline_prepare(cpu);
+ break;
+
+ case CPU_POST_DEAD:
+ cpufreq_offline_finish(cpu);
+ break;
+
+ case CPU_DOWN_FAILED:
+ cpufreq_online(cpu);
+ break;
}
return NOTIFY_OK;
}
--
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