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authorLai Jiangshan <laijs@cn.fujitsu.com>2010-05-26 14:43:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 09:12:48 -0700
commit79a6cdeb7eb54e3d2d4bb9fc5f0231b057882a87 (patch)
tree2a80342946cf206002ce5dcf32f097320f64fdd1 /kernel/cpu.c
parentc9d221f86e43d9fb16260fe18a8cd6767f36c8a5 (diff)
downloadlinux-2.6.34-ux500-79a6cdeb7eb54e3d2d4bb9fc5f0231b057882a87.tar.gz
cpuhotplug: do not need cpu_hotplug_begin() when CONFIG_HOTPLUG_CPU=n
Since when CONFIG_HOTPLUG_CPU=n, get_online_cpus() do nothing, so we don't need cpu_hotplug_begin() either. This patch moves cpu_hotplug_begin()/cpu_hotplug_done() into the code block of CONFIG_HOTPLUG_CPU=y. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c40
1 files changed, 22 insertions, 18 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 0690ac27a25..63e8de13c94 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -20,6 +20,20 @@
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
static DEFINE_MUTEX(cpu_add_remove_lock);
+/*
+ * The following two API's must be used when attempting
+ * to serialize the updates to cpu_online_mask, cpu_present_mask.
+ */
+void cpu_maps_update_begin(void)
+{
+ mutex_lock(&cpu_add_remove_lock);
+}
+
+void cpu_maps_update_done(void)
+{
+ mutex_unlock(&cpu_add_remove_lock);
+}
+
static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
@@ -27,6 +41,8 @@ static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
*/
static int cpu_hotplug_disabled;
+#ifdef CONFIG_HOTPLUG_CPU
+
static struct {
struct task_struct *active_writer;
struct mutex lock; /* Synchronizes accesses to refcount, */
@@ -41,8 +57,6 @@ static struct {
.refcount = 0,
};
-#ifdef CONFIG_HOTPLUG_CPU
-
void get_online_cpus(void)
{
might_sleep();
@@ -67,22 +81,6 @@ void put_online_cpus(void)
}
EXPORT_SYMBOL_GPL(put_online_cpus);
-#endif /* CONFIG_HOTPLUG_CPU */
-
-/*
- * The following two API's must be used when attempting
- * to serialize the updates to cpu_online_mask, cpu_present_mask.
- */
-void cpu_maps_update_begin(void)
-{
- mutex_lock(&cpu_add_remove_lock);
-}
-
-void cpu_maps_update_done(void)
-{
- mutex_unlock(&cpu_add_remove_lock);
-}
-
/*
* This ensures that the hotplug operation can begin only when the
* refcount goes to zero.
@@ -124,6 +122,12 @@ static void cpu_hotplug_done(void)
cpu_hotplug.active_writer = NULL;
mutex_unlock(&cpu_hotplug.lock);
}
+
+#else /* #if CONFIG_HOTPLUG_CPU */
+static void cpu_hotplug_begin(void) {}
+static void cpu_hotplug_done(void) {}
+#endif /* #esle #if CONFIG_HOTPLUG_CPU */
+
/* Need to know about CPUs going up/down? */
int __ref register_cpu_notifier(struct notifier_block *nb)
{