genirq: Restrict effective affinity to interrupts actually using it

Just because CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK is selected
doesn't mean that all the interrupts are using the effective
affinity mask. For a number of them, this mask is likely to
be empty.

In order to deal with this, let's restrict the use of the
effective affinity mask to these interrupts that have a non empty
effective affinity.

Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Jason Cooper <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: Kevin Cernekee <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Gregory Clement <[email protected]>
Cc: Matt Redfearn <[email protected]>
Cc: Sebastian Hesselbarth <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index d2d543794093..dcfac6c8ba18 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -781,7 +781,10 @@ static inline struct cpumask *irq_data_get_affinity_mask(struct irq_data *d)
 static inline
 struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
 {
-	return d->common->effective_affinity;
+	if (!cpumask_empty(d->common->effective_affinity))
+		return d->common->effective_affinity;
+
+	return d->common->affinity;
 }
 static inline void irq_data_update_effective_affinity(struct irq_data *d,
 						      const struct cpumask *m)