[PATCH] msi: simplify msi sanity checks by adding with generic irq code

Currently msi.c is doing sanity checks that make certain before an irq is
destroyed it has no more users.

By adding irq_has_action I can perform the test is a generic way, instead of
relying on a msi specific data structure.

By performing the core check in dynamic_irq_cleanup I ensure every user of
dynamic irqs has a test present and we don't free resources that are in use.

In msi.c this allows me to kill the attrib.state member of msi_desc and all of
the assciated code to maintain it.

To keep from freeing data structures when irq cleanup code is called to soon
changing dyanamic_irq_cleanup is insufficient because there are msi specific
data structures that are also not safe to free.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 69855b2..6f46360 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -372,6 +372,13 @@ set_irq_chained_handler(unsigned int irq,
 extern int create_irq(void);
 extern void destroy_irq(unsigned int irq);
 
+/* Test to see if a driver has successfully requested an irq */
+static inline int irq_has_action(unsigned int irq)
+{
+	struct irq_desc *desc = irq_desc + irq;
+	return desc->action != NULL;
+}
+
 /* Dynamic irq helper functions */
 extern void dynamic_irq_init(unsigned int irq);
 extern void dynamic_irq_cleanup(unsigned int irq);