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Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 81e2a38..356450f 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -79,6 +79,8 @@ static struct {
/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
+#define cpuhp_lock_acquire_tryread() \
+ lock_map_acquire_tryread(&cpu_hotplug.dep_map)
#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
@@ -91,10 +93,22 @@ void get_online_cpus(void)
mutex_lock(&cpu_hotplug.lock);
cpu_hotplug.refcount++;
mutex_unlock(&cpu_hotplug.lock);
-
}
EXPORT_SYMBOL_GPL(get_online_cpus);
+bool try_get_online_cpus(void)
+{
+ if (cpu_hotplug.active_writer == current)
+ return true;
+ if (!mutex_trylock(&cpu_hotplug.lock))
+ return false;
+ cpuhp_lock_acquire_tryread();
+ cpu_hotplug.refcount++;
+ mutex_unlock(&cpu_hotplug.lock);
+ return true;
+}
+EXPORT_SYMBOL_GPL(try_get_online_cpus);
+
void put_online_cpus(void)
{
if (cpu_hotplug.active_writer == current)
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