From: Ingo Molnar <mingo@elte.hu>

Teach special (recursive) locking code to the lock validator.  Has no effect
on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 kernel/irq/handle.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff -puN kernel/irq/handle.c~lock-validator-special-locking-genirq kernel/irq/handle.c
--- a/kernel/irq/handle.c~lock-validator-special-locking-genirq
+++ a/kernel/irq/handle.c
@@ -15,6 +15,7 @@
 #include <linux/random.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
+#include <linux/kallsyms.h>
 
 #include "internals.h"
 
@@ -242,3 +243,15 @@ out:
 	return 1;
 }
 
+/*
+ * lockdep: we want to handle all irq_desc locks as a single lock-type:
+ */
+static struct lockdep_type_key irq_desc_lock_type;
+
+void early_init_irq_lock_type(void)
+{
+	int i;
+
+	for (i = 0; i < NR_IRQS; i++)
+		spin_lock_init_key(&irq_desc[i].lock, &irq_desc_lock_type);
+}
_