cpu topology: consider sysfs_create_group return value

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@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 32 insertions, 23 deletions

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 28dccb730af9..3d12b85b0962 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -94,54 +94,63 @@ static struct attribute_group topology_attr_group = {
         .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);
-