IRQ affinity masks are not allocated in uniprocessor configurations.
This requires special case non-SMP code in drivers for irqchips which
have per-CPU enable or mask registers.
Since IRQ affinity is always the same in a uniprocessor configuration,
we can provide a correct affinity mask without allocating one per IRQ.
By returning a real cpumask from irq_data_get_affinity_mask even when
SMP is disabled, irqchip drivers which iterate over that mask will
automatically do the right thing.
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
Changes in v3:
- Use cpumask_of(0) instead of cpu_possible_mask
include/linux/irq.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 02073f7a156e..996e22744edd 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -151,7 +151,9 @@ struct irq_common_data {
#endif
void *handler_data;
struct msi_desc *msi_desc;
+#ifdef CONFIG_SMP
cpumask_var_t affinity;
+#endif
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
cpumask_var_t effective_affinity;
#endif
@@ -882,13 +884,19 @@ static inline int irq_data_get_node(struct irq_data *d)
static inline
const struct cpumask *irq_data_get_affinity_mask(struct irq_data *d)
{
+#ifdef CONFIG_SMP
return d->common->affinity;
+#else
+ return cpumask_of(0);
+#endif
}
static inline void irq_data_update_affinity(struct irq_data *d,
const struct cpumask *m)
{
+#ifdef CONFIG_SMP
cpumask_copy(d->common->affinity, m);
+#endif
}
static inline const struct cpumask *irq_get_affinity_mask(int irq)
--
2.35.1
