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-rw-r--r--kernel/cpu.c40
1 files changed, 22 insertions, 18 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 0690ac27a253..63e8de13c948 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -20,6 +20,20 @@
20/* Serializes the updates to cpu_online_mask, cpu_present_mask */ 20/* Serializes the updates to cpu_online_mask, cpu_present_mask */
21static DEFINE_MUTEX(cpu_add_remove_lock); 21static DEFINE_MUTEX(cpu_add_remove_lock);
22 22
23/*
24 * The following two API's must be used when attempting
25 * to serialize the updates to cpu_online_mask, cpu_present_mask.
26 */
27void cpu_maps_update_begin(void)
28{
29 mutex_lock(&cpu_add_remove_lock);
30}
31
32void cpu_maps_update_done(void)
33{
34 mutex_unlock(&cpu_add_remove_lock);
35}
36
23static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain); 37static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
24 38
25/* If set, cpu_up and cpu_down will return -EBUSY and do nothing. 39/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
@@ -27,6 +41,8 @@ static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
27 */ 41 */
28static int cpu_hotplug_disabled; 42static int cpu_hotplug_disabled;
29 43
44#ifdef CONFIG_HOTPLUG_CPU
45
30static struct { 46static struct {
31 struct task_struct *active_writer; 47 struct task_struct *active_writer;
32 struct mutex lock; /* Synchronizes accesses to refcount, */ 48 struct mutex lock; /* Synchronizes accesses to refcount, */
@@ -41,8 +57,6 @@ static struct {
41 .refcount = 0, 57 .refcount = 0,
42}; 58};
43 59
44#ifdef CONFIG_HOTPLUG_CPU
45
46void get_online_cpus(void) 60void get_online_cpus(void)
47{ 61{
48 might_sleep(); 62 might_sleep();
@@ -67,22 +81,6 @@ void put_online_cpus(void)
67} 81}
68EXPORT_SYMBOL_GPL(put_online_cpus); 82EXPORT_SYMBOL_GPL(put_online_cpus);
69 83
70#endif /* CONFIG_HOTPLUG_CPU */
71
72/*
73 * The following two API's must be used when attempting
74 * to serialize the updates to cpu_online_mask, cpu_present_mask.
75 */
76void cpu_maps_update_begin(void)
77{
78 mutex_lock(&cpu_add_remove_lock);
79}
80
81void cpu_maps_update_done(void)
82{
83 mutex_unlock(&cpu_add_remove_lock);
84}
85
86/* 84/*
87 * This ensures that the hotplug operation can begin only when the 85 * This ensures that the hotplug operation can begin only when the
88 * refcount goes to zero. 86 * refcount goes to zero.
@@ -124,6 +122,12 @@ static void cpu_hotplug_done(void)
124 cpu_hotplug.active_writer = NULL; 122 cpu_hotplug.active_writer = NULL;
125 mutex_unlock(&cpu_hotplug.lock); 123 mutex_unlock(&cpu_hotplug.lock);
126} 124}
125
126#else /* #if CONFIG_HOTPLUG_CPU */
127static void cpu_hotplug_begin(void) {}
128static void cpu_hotplug_done(void) {}
129#endif /* #esle #if CONFIG_HOTPLUG_CPU */
130
127/* Need to know about CPUs going up/down? */ 131/* Need to know about CPUs going up/down? */
128int __ref register_cpu_notifier(struct notifier_block *nb) 132int __ref register_cpu_notifier(struct notifier_block *nb)
129{ 133{