drivers base/topology: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs. No functional change

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161103145021.28528-14-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index df3c97cb4c9982eaf391390bda0cbe0b0db570e5..d6ec1c546f5b485fae183d51df23189481b568ec 100644 (file)
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -118,51 +118,19 @@ static int topology_add_dev(unsigned int cpu)
        return sysfs_create_group(&dev->kobj, &topology_attr_group);
 }
 
-static void topology_remove_dev(unsigned int cpu)
+static int topology_remove_dev(unsigned int cpu)
 {
        struct device *dev = get_cpu_device(cpu);
 
        sysfs_remove_group(&dev->kobj, &topology_attr_group);
-}
-
-static int topology_cpu_callback(struct notifier_block *nfb,
-                                unsigned long action, void *hcpu)
-{
-       unsigned int cpu = (unsigned long)hcpu;
-       int rc = 0;
-
-       switch (action) {
-       case CPU_UP_PREPARE:
-       case CPU_UP_PREPARE_FROZEN:
-               rc = topology_add_dev(cpu);
-               break;
-       case CPU_UP_CANCELED:
-       case CPU_UP_CANCELED_FROZEN:
-       case CPU_DEAD:
-       case CPU_DEAD_FROZEN:
-               topology_remove_dev(cpu);
-               break;
-       }
-       return notifier_from_errno(rc);
+       return 0;
 }
 
 static int topology_sysfs_init(void)
 {
-       int cpu;
-       int rc = 0;
-
-       cpu_notifier_register_begin();
-
-       for_each_online_cpu(cpu) {
-               rc = topology_add_dev(cpu);
-               if (rc)
-                       goto out;
-       }
-       __hotcpu_notifier(topology_cpu_callback, 0);
-
-out:
-       cpu_notifier_register_done();
-       return rc;
+       return cpuhp_setup_state(CPUHP_TOPOLOGY_PREPARE,
+                                "base/topology:prepare", topology_add_dev,
+                                topology_remove_dev);
 }
 
 device_initcall(topology_sysfs_init);

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 86b940f19df866316646b62a5359a493bd0c3967..3410d83cc2e2ddf0cb4cc0e1d3ce06d84ecf9e63 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -57,6 +57,7 @@ enum cpuhp_state {
        CPUHP_SH_SH3X_PREPARE,
        CPUHP_BLK_MQ_PREPARE,
        CPUHP_NET_FLOW_PREPARE,
+       CPUHP_TOPOLOGY_PREPARE,
        CPUHP_TIMERS_DEAD,
        CPUHP_NOTF_ERR_INJ_PREPARE,
        CPUHP_MIPS_SOC_PREPARE,