[PATCH] lockdep: annotate genirq

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>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 80ec7a4dbc98..316e0fb8d7b1 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -270,6 +270,12 @@ static inline int lockdep_internal(void)
 struct lock_class_key { };
 #endif /* !LOCKDEP */
 
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
+extern void early_init_irq_lock_class(void);
+#else
+# define early_init_irq_lock_class()            do { } while (0)
+#endif
+
 #ifdef CONFIG_TRACE_IRQFLAGS
 extern void early_boot_irqs_off(void);
 extern void early_boot_irqs_on(void);
diff --git a/init/main.c b/init/main.c
index fc473d4b56fd..628b8e9e841a 100644
--- a/init/main.c
+++ b/init/main.c
@@ -466,6 +466,7 @@ asmlinkage void __init start_kernel(void)
 
         local_irq_disable();
         early_boot_irqs_off();
+        early_init_irq_lock_class();
 
 /*
  * Interrupts are still disabled. Do necessary setups, then
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index aeb6e391276c..a7b497ee919e 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -249,3 +249,19 @@ out:
         return 1;
 }
 
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+/*
+ * lockdep: we want to handle all irq_desc locks as a single lock-class:
+ */
+static struct lock_class_key irq_desc_lock_class;
+
+void early_init_irq_lock_class(void)
+{
+        int i;
+
+        for (i = 0; i < NR_IRQS; i++)
+                lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
+}
+
+#endif