[RESEND PATCH] genirq: warn about IRQF_SHARED|IRQF_DISABLED at the right place

From: Uwe Kleine-KÃnig
Date: Tue Jan 12 2010 - 10:42:20 EST

For shared irqs IRQF_DISABLED is only guaranteed for the first handler.
So only warn starting at the second registration.

The warning is moved to __setup_irq having the additional benefit of
catching actions registered using setup_irq not only register_irq.

This doesn't fix the cases where setup order is wrong but it should
report the broken cases more reliably.

Signed-off-by: Uwe Kleine-KÃnig <u.kleine-koenig@xxxxxxxxxxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Nicolas Pitre <nico@xxxxxxxxxxx>
Cc: Eric Miao <eric.y.miao@xxxxxxxxx>
Cc: John Stultz <johnstul@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Remy Bohmer <linux@xxxxxxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: Andrea Gallo <andrea.gallo@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jamie Lokier <jamie@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx

until Thomas or Peter get round to dump IRQF_DISABLED completely this
patch removes some false positive warnings and adds a valid warning in
some situations that weren't catched before.

Best regards

kernel/irq/manage.c | 23 ++++++++++-------------
1 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index bde4c66..d8f7415 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -702,6 +702,16 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
goto mismatch;

+ /*
+ * handle_IRQ_event() only honors IRQF_DISABLED for the _first_
+ * irqaction. As the first handler might reenable irqs all bets
+ * are off for the later handlers even if the first one has
+ */
+ if (new->flags & IRQF_DISABLED)
+ pr_warning("IRQ %d/%s: IRQF_DISABLED is not guaranteed "
+ "on shared IRQs\n", irq, new->name);
/* add new interrupt at end of irq queue */
do {
old_ptr = &old->next;
@@ -1008,19 +1018,6 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
struct irq_desc *desc;
int retval;

- /*
- * handle_IRQ_event() always ignores IRQF_DISABLED except for
- * the _first_ irqaction (sigh). That can cause oopsing, but
- * the behavior is classified as "will not fix" so we need to
- * start nudging drivers away from using that idiom.
- */
- if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
- pr_warning(
- "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
- irq, devname);
- }
* Lockdep wants atomic interrupt handlers:

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/