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path: root/drivers/cpufreq/cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c27
1 files changed, 11 insertions, 16 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 6c6121b85a5..23a63207d74 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -38,7 +38,6 @@ static struct cpufreq_driver *cpufreq_driver;
static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
static DEFINE_SPINLOCK(cpufreq_driver_lock);
-
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
static void handle_update(void *data);
@@ -593,12 +592,11 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
goto module_out;
}
- policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
+ policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
if (!policy) {
ret = -ENOMEM;
goto nomem_out;
}
- memset(policy, 0, sizeof(struct cpufreq_policy));
policy->cpu = cpu;
policy->cpus = cpumask_of_cpu(cpu);
@@ -1116,24 +1114,21 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
int retval = -EINVAL;
/*
- * Converted the lock_cpu_hotplug to preempt_disable()
- * and preempt_enable(). This is a bit kludgy and relies on how cpu
- * hotplug works. All we need is a guarantee that cpu hotplug won't make
- * progress on any cpu. Once we do preempt_disable(), this would ensure
- * that hotplug threads don't get onto this cpu, thereby delaying
- * the cpu remove process.
- *
- * We removed the lock_cpu_hotplug since we need to call this function
- * via cpu hotplug callbacks, which result in locking the cpu hotplug
- * thread itself. Agree this is not very clean, cpufreq community
- * could improve this if required. - Ashok Raj <ashok.raj@intel.com>
+ * If we are already in context of hotplug thread, we dont need to
+ * acquire the hotplug lock. Otherwise acquire cpucontrol to prevent
+ * hotplug from removing this cpu that we are working on.
*/
- preempt_disable();
+ if (!current_in_cpu_hotplug())
+ lock_cpu_hotplug();
+
dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
target_freq, relation);
if (cpu_online(policy->cpu) && cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);
- preempt_enable();
+
+ if (!current_in_cpu_hotplug())
+ unlock_cpu_hotplug();
+
return retval;
}
EXPORT_SYMBOL_GPL(__cpufreq_driver_target);