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Date: Thu, 23 Jul 2015 02:04:06 +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 2/2] 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_dev_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.
Suggested-by: Russell King <linux@....linux.org.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
drivers/cpufreq/cpufreq.c | 109 +++++++++++++++++++++++-----------------------
1 file changed, 56 insertions(+), 53 deletions(-)
Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -1177,45 +1177,14 @@ 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 int cpufreq_dev_online(struct device *dev, bool recover_policy)
{
unsigned int j, cpu = dev->id;
int ret = -ENOMEM;
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
unsigned long flags;
- bool recover_policy = !sif;
- pr_debug("adding CPU %u\n", cpu);
-
- /* sysfs links are only created on subsys callback */
- if (sif && policy) {
- pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
- ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
- if (ret) {
- dev_dbg(dev, "%s: Failed to create link (%d)\n",
- __func__, ret);
- return ret;
- }
-
- /* Track CPUs for which sysfs links are created */
- cpumask_set_cpu(cpu, policy->linked_cpus);
- }
-
- /*
- * A hotplug notifier will follow and we will take care of rest
- * of the initialization then.
- */
- if (cpu_is_offline(cpu))
- return 0;
+ pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
if (!down_read_trylock(&cpufreq_rwsem))
return 0;
@@ -1376,6 +1345,36 @@ out_release_rwsem:
return ret;
}
+/**
+ * cpufreq_add_dev - add a cpufreq interface to a CPU device.
+ * @dev: CPU device to add the interface to.
+ * @sif: Subsystem interface pointer.
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+ unsigned int cpu = dev->id;
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
+
+ pr_debug("%s: adding CPU %u\n", __func__, cpu);
+
+ if (policy && policy->kobj_cpu != cpu) {
+ int ret;
+
+ pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
+ ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
+ if (ret) {
+ dev_dbg(dev, "%s: Failed to create link (%d)\n",
+ __func__, ret);
+ return ret;
+ }
+
+ /* Track CPUs for which sysfs links are created */
+ cpumask_set_cpu(cpu, policy->linked_cpus);
+ }
+
+ return cpu_online(cpu) ? cpufreq_dev_online(dev, false) : 0;
+}
+
static void cpufreq_offline_prepare(unsigned int cpu)
{
struct cpufreq_policy *policy;
@@ -2344,31 +2343,35 @@ unlock:
}
EXPORT_SYMBOL(cpufreq_update_policy);
+static void cpufreq_cpu_online(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+
+ if (dev)
+ cpufreq_dev_online(dev, true);
+}
+
static int cpufreq_cpu_callback(struct notifier_block *nfb,
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_cpu_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_cpu_online(cpu);
+ break;
}
return NOTIFY_OK;
}
--
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