genirq: Add and use an irq_data_update_affinity helper

Some architectures and irqchip drivers modify the cpumask returned by
irq_data_get_affinity_mask, usually by copying in to it. This is
problematic for uniprocessor configurations, where the affinity mask
should be constant, as it is known at compile time.

Add and use a setter for the affinity mask, following the pattern of
irq_data_update_effective_affinity. This allows the getter function to
return a const cpumask pointer.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Xen bits
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220701200056.46555-7-samuel@sholland.org

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
index f6d2946edbd2..15f2effd6baf 100644
--- a/arch/alpha/kernel/irq.c
+++ b/arch/alpha/kernel/irq.c
@@ -60,7 +60,7 @@ int irq_select_affinity(unsigned int irq)
 		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
 	last_cpu = cpu;
 
-	cpumask_copy(irq_data_get_affinity_mask(data), cpumask_of(cpu));
+	irq_data_update_affinity(data, cpumask_of(cpu));
 	chip->irq_set_affinity(data, cpumask_of(cpu), false);
 	return 0;
 }