switch the protection of percpu_counter list to spinlock
... making percpu_counter_destroy() non-blocking
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index f8a3f1a..ba6085d 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -12,7 +12,7 @@
#ifdef CONFIG_HOTPLUG_CPU
static LIST_HEAD(percpu_counters);
-static DEFINE_MUTEX(percpu_counters_lock);
+static DEFINE_SPINLOCK(percpu_counters_lock);
#endif
#ifdef CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER
@@ -123,9 +123,9 @@
#ifdef CONFIG_HOTPLUG_CPU
INIT_LIST_HEAD(&fbc->list);
- mutex_lock(&percpu_counters_lock);
+ spin_lock(&percpu_counters_lock);
list_add(&fbc->list, &percpu_counters);
- mutex_unlock(&percpu_counters_lock);
+ spin_unlock(&percpu_counters_lock);
#endif
return 0;
}
@@ -139,9 +139,9 @@
debug_percpu_counter_deactivate(fbc);
#ifdef CONFIG_HOTPLUG_CPU
- mutex_lock(&percpu_counters_lock);
+ spin_lock(&percpu_counters_lock);
list_del(&fbc->list);
- mutex_unlock(&percpu_counters_lock);
+ spin_unlock(&percpu_counters_lock);
#endif
free_percpu(fbc->counters);
fbc->counters = NULL;
@@ -170,7 +170,7 @@
return NOTIFY_OK;
cpu = (unsigned long)hcpu;
- mutex_lock(&percpu_counters_lock);
+ spin_lock(&percpu_counters_lock);
list_for_each_entry(fbc, &percpu_counters, list) {
s32 *pcount;
unsigned long flags;
@@ -181,7 +181,7 @@
*pcount = 0;
raw_spin_unlock_irqrestore(&fbc->lock, flags);
}
- mutex_unlock(&percpu_counters_lock);
+ spin_unlock(&percpu_counters_lock);
#endif
return NOTIFY_OK;
}