[PATCH 28/36] cpu topology: consider sysfs_create_group return value

From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>

Take return value of sysfs_create_group() into account. That function got
called in case of CPU_ONLINE notification. Since callbacks are not allowed
to fail on CPU_ONLINE notification do the sysfs group creation on
CPU_UP_PREPARE notification.

Also remember if creation succeeded in a bitmask. So it's possible to know
whether it's legal to call sysfs_remove_group or not.

In addition some other minor stuff:

- since CPU_UP_PREPARE might fail add CPU_UP_CANCELED handling as well.
- use hotcpu_notifier instead of register_hotcpu_notifier.
- #ifdef code that isn't needed in the !CONFIG_HOTPLUG_CPU case.

Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Acked-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/base/topology.c | 55 +++++++++++++++++++++++++++-------------------
1 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 28dccb7..3d12b85 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -94,54 +94,63 @@ static struct attribute_group topology_a
.name = "topology"
};

+static cpumask_t topology_dev_map = CPU_MASK_NONE;
+
/* Add/Remove cpu_topology interface for CPU device */
-static int __cpuinit topology_add_dev(struct sys_device * sys_dev)
+static int __cpuinit topology_add_dev(unsigned int cpu)
{
- return sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
+ int rc;
+ struct sys_device *sys_dev = get_cpu_sysdev(cpu);
+
+ rc = sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
+ if (!rc)
+ cpu_set(cpu, topology_dev_map);
+ return rc;
}

-static int __cpuinit topology_remove_dev(struct sys_device * sys_dev)
+#ifdef CONFIG_HOTPLUG_CPU
+static void __cpuinit topology_remove_dev(unsigned int cpu)
{
+ struct sys_device *sys_dev = get_cpu_sysdev(cpu);
+
+ if (!cpu_isset(cpu, topology_dev_map))
+ return;
+ cpu_clear(cpu, topology_dev_map);
sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
- return 0;
}

static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+ unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
- struct sys_device *sys_dev;
+ int rc = 0;

- sys_dev = get_cpu_sysdev(cpu);
switch (action) {
- case CPU_ONLINE:
- topology_add_dev(sys_dev);
+ case CPU_UP_PREPARE:
+ rc = topology_add_dev(cpu);
break;
+ case CPU_UP_CANCELED:
case CPU_DEAD:
- topology_remove_dev(sys_dev);
+ topology_remove_dev(cpu);
break;
}
- return NOTIFY_OK;
+ return rc ? NOTIFY_BAD : NOTIFY_OK;
}
-
-static struct notifier_block __cpuinitdata topology_cpu_notifier =
-{
- .notifier_call = topology_cpu_callback,
-};
+#endif

static int __cpuinit topology_sysfs_init(void)
{
- int i;
+ int cpu;
+ int rc;

- for_each_online_cpu(i) {
- topology_cpu_callback(&topology_cpu_notifier, CPU_ONLINE,
- (void *)(long)i);
+ for_each_online_cpu(cpu) {
+ rc = topology_add_dev(cpu);
+ if (rc)
+ return rc;
}
-
- register_hotcpu_notifier(&topology_cpu_notifier);
+ hotcpu_notifier(topology_cpu_callback, 0);

return 0;
}

device_initcall(topology_sysfs_init);
-
--
1.4.4.1

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