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authorPrarit Bhargava <prarit@redhat.com>2009-11-12 09:18:46 -0500
committerDave Jones <davej@redhat.com>2009-11-17 23:15:04 -0500
commit90e41bac100e34f955f48e7686c2fc685ac9aa30 (patch)
tree50ae248a292e85d3e784d12e2e6a37823048d98b
parent54c9a35d9faef06e00e2a941eb8fe674f1886901 (diff)
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[CPUFREQ] Fix stale cpufreq_cpu_governor pointer
Dave, Attached is an update of my patch against the cpufreq fixes branch. Before applying the patch I compiled and booted the tree to see if the panic was still there -- to my surprise it was not. This is because of the conversion of cpufreq_cpu_governor to a char[]. While the panic is kaput, the problem of stale data continues and my patch is still valid. It is possible to end up with the wrong governor after hotplug events because CPUFREQ_DEFAULT_GOVERNOR is statically linked to a default, while the cpu siblings may have had a different governor assigned by a user. ie) the patch is still needed in order to keep the governors assigned properly when hotplugging devices Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Dave Jones <davej@redhat.com>
-rw-r--r--drivers/cpufreq/cpufreq.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index dab1410d1c0..ff57c40e9b8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -951,10 +951,13 @@ err_out_kobj_put:
static int cpufreq_add_dev(struct sys_device *sys_dev)
{
unsigned int cpu = sys_dev->id;
- int ret = 0;
+ int ret = 0, found = 0;
struct cpufreq_policy *policy;
unsigned long flags;
unsigned int j;
+#ifdef CONFIG_HOTPLUG_CPU
+ int sibling;
+#endif
if (cpu_is_offline(cpu))
return 0;
@@ -1001,7 +1004,19 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
INIT_WORK(&policy->update, handle_update);
/* Set governor before ->init, so that driver could check it */
- policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+#ifdef CONFIG_HOTPLUG_CPU
+ for_each_online_cpu(sibling) {
+ struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
+ if (cp && cp->governor &&
+ (cpumask_test_cpu(cpu, cp->related_cpus))) {
+ policy->governor = cp->governor;
+ found = 1;
+ break;
+ }
+ }
+#endif
+ if (!found)
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
/* call driver. From then on the cpufreq must be able
* to accept all calls to ->verify and ->setpolicy for this CPU
*/
@@ -1610,9 +1625,22 @@ EXPORT_SYMBOL_GPL(cpufreq_register_governor);
void cpufreq_unregister_governor(struct cpufreq_governor *governor)
{
+#ifdef CONFIG_HOTPLUG_CPU
+ int cpu;
+#endif
+
if (!governor)
return;
+#ifdef CONFIG_HOTPLUG_CPU
+ for_each_present_cpu(cpu) {
+ if (cpu_online(cpu))
+ continue;
+ if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
+ strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
+ }
+#endif
+
mutex_lock(&cpufreq_governor_mutex);
list_del(&governor->governor_list);
mutex_unlock(&cpufreq_governor_mutex);