[PATCH v2 43/52] thermal, x86-pkg-temp: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(_cpu_notifier);
cpu_notifier_register_done();
Fix the thermal x86-pkg-temp code by using this latter form of callback
registration.
Cc: Zhang Rui
Cc: Eduardo Valentin
Cc: Ingo Molnar
Cc: linux...@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat
---
drivers/thermal/x86_pkg_temp_thermal.c | 14 +++---
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/thermal/x86_pkg_temp_thermal.c
b/drivers/thermal/x86_pkg_temp_thermal.c
index 972e1c7..7592048 100644
--- a/drivers/thermal/x86_pkg_temp_thermal.c
+++ b/drivers/thermal/x86_pkg_temp_thermal.c
@@ -589,12 +589,12 @@ static int __init pkg_temp_thermal_init(void)
platform_thermal_package_rate_control =
pkg_temp_thermal_platform_thermal_rate_control;
- get_online_cpus();
+ cpu_notifier_register_begin();
for_each_online_cpu(i)
if (get_core_online(i))
goto err_ret;
- register_hotcpu_notifier(_temp_thermal_notifier);
- put_online_cpus();
+ __register_hotcpu_notifier(_temp_thermal_notifier);
+ cpu_notifier_register_done();
pkg_temp_debugfs_init(); /* Don't care if fails */
@@ -603,7 +603,7 @@ static int __init pkg_temp_thermal_init(void)
err_ret:
for_each_online_cpu(i)
put_core_offline(i);
- put_online_cpus();
+ cpu_notifier_register_done();
kfree(pkg_work_scheduled);
platform_thermal_package_notify = NULL;
platform_thermal_package_rate_control = NULL;
@@ -616,8 +616,8 @@ static void __exit pkg_temp_thermal_exit(void)
struct phy_dev_entry *phdev, *n;
int i;
- get_online_cpus();
- unregister_hotcpu_notifier(_temp_thermal_notifier);
+ cpu_notifier_register_begin();
+ __unregister_hotcpu_notifier(_temp_thermal_notifier);
mutex_lock(_dev_list_mutex);
list_for_each_entry_safe(phdev, n, _dev_list, list) {
/* Retore old MSR value for package thermal interrupt */
@@ -635,7 +635,7 @@ static void __exit pkg_temp_thermal_exit(void)
for_each_online_cpu(i)
cancel_delayed_work_sync(
_cpu(pkg_temp_thermal_threshold_work, i));
- put_online_cpus();
+ cpu_notifier_register_done();
kfree(pkg_work_scheduled);
--
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[PATCH v2 43/52] thermal, x86-pkg-temp: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the thermal x86-pkg-temp code by using this latter form of callback
registration.
Cc: Zhang Rui rui.zh...@intel.com
Cc: Eduardo Valentin eduardo.valen...@ti.com
Cc: Ingo Molnar mi...@kernel.org
Cc: linux...@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat srivatsa.b...@linux.vnet.ibm.com
---
drivers/thermal/x86_pkg_temp_thermal.c | 14 +++---
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/thermal/x86_pkg_temp_thermal.c
b/drivers/thermal/x86_pkg_temp_thermal.c
index 972e1c7..7592048 100644
--- a/drivers/thermal/x86_pkg_temp_thermal.c
+++ b/drivers/thermal/x86_pkg_temp_thermal.c
@@ -589,12 +589,12 @@ static int __init pkg_temp_thermal_init(void)
platform_thermal_package_rate_control =
pkg_temp_thermal_platform_thermal_rate_control;
- get_online_cpus();
+ cpu_notifier_register_begin();
for_each_online_cpu(i)
if (get_core_online(i))
goto err_ret;
- register_hotcpu_notifier(pkg_temp_thermal_notifier);
- put_online_cpus();
+ __register_hotcpu_notifier(pkg_temp_thermal_notifier);
+ cpu_notifier_register_done();
pkg_temp_debugfs_init(); /* Don't care if fails */
@@ -603,7 +603,7 @@ static int __init pkg_temp_thermal_init(void)
err_ret:
for_each_online_cpu(i)
put_core_offline(i);
- put_online_cpus();
+ cpu_notifier_register_done();
kfree(pkg_work_scheduled);
platform_thermal_package_notify = NULL;
platform_thermal_package_rate_control = NULL;
@@ -616,8 +616,8 @@ static void __exit pkg_temp_thermal_exit(void)
struct phy_dev_entry *phdev, *n;
int i;
- get_online_cpus();
- unregister_hotcpu_notifier(pkg_temp_thermal_notifier);
+ cpu_notifier_register_begin();
+ __unregister_hotcpu_notifier(pkg_temp_thermal_notifier);
mutex_lock(phy_dev_list_mutex);
list_for_each_entry_safe(phdev, n, phy_dev_list, list) {
/* Retore old MSR value for package thermal interrupt */
@@ -635,7 +635,7 @@ static void __exit pkg_temp_thermal_exit(void)
for_each_online_cpu(i)
cancel_delayed_work_sync(
per_cpu(pkg_temp_thermal_threshold_work, i));
- put_online_cpus();
+ cpu_notifier_register_done();
kfree(pkg_work_scheduled);
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
