After fixing the CPU hotplug callback registration code, the callbacks
invoked for each online CPU, during the initialization phase in
thermal_throttle_init_device(), can no longer race with the actual CPU
hotplug notifier callbacks (in thermal_throttle_cpu_callback). Hence the
therm_cpu_lock is unnecessary now. Remove it.
Cc: Tony Luck <tony.l...@intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: linux-e...@vger.kernel.org
Suggested-by: Oleg Nesterov <o...@redhat.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
---
arch/x86/kernel/cpu/mcheck/therm_throt.c | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c
b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index e05dfa3..d921b7e 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -271,9 +271,6 @@ static void thermal_throttle_remove_dev(struct device *dev)
sysfs_remove_group(&dev->kobj, &thermal_attr_group);
}
-/* Mutex protecting device creation against CPU hotplug: */
-static DEFINE_MUTEX(therm_cpu_lock);
-
/* Get notified when a cpu comes on/off. Be hotplug friendly. */
static int
thermal_throttle_cpu_callback(struct notifier_block *nfb,
@@ -289,18 +286,14 @@ thermal_throttle_cpu_callback(struct notifier_block *nfb,
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
- mutex_lock(&therm_cpu_lock);
err = thermal_throttle_add_dev(dev, cpu);
- mutex_unlock(&therm_cpu_lock);
WARN_ON(err);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- mutex_lock(&therm_cpu_lock);
thermal_throttle_remove_dev(dev);
- mutex_unlock(&therm_cpu_lock);
break;
}
return notifier_from_errno(err);
@@ -321,17 +314,11 @@ static __init int thermal_throttle_init_device(void)
cpu_notifier_register_begin();
-#ifdef CONFIG_HOTPLUG_CPU
- mutex_lock(&therm_cpu_lock);
-#endif
/* connect live CPUs to sysfs */
for_each_online_cpu(cpu) {
err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
WARN_ON(err);
}
-#ifdef CONFIG_HOTPLUG_CPU
- mutex_unlock(&therm_cpu_lock);
-#endif
__register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
cpu_notifier_register_done();
--
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