Re: [PATCH 00/07] dyn_array/nr_irqs/sparse_irq support v10 - fix

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Fri, 2008-08-15 at 11:35 +0200, Ingo Molnar wrote:

> looks wrong - it should be unconditional (i've done that via the patch 
> below). I dont remember why we made early_init_irq_lock_class() 
> dependent on CONFIG_TRACE_IRQFLAGS before. Peter, do you have any 
> memories?

Nope, git suggests I poke you about it.. :-)

commit 243c7621aac4ed1aa79524c9a1cecf7c05a28124
Author: Ingo Molnar <mingo@elte.hu>
Date:   Mon Jul 3 00:25:06 2006 -0700

    [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>

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 80ec7a4..316e0fb 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 fc473d4..628b8e9 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 aeb6e39..a7b497e 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