sparc/irq: Remove on-stack cpumask var

In general it's preferable to avoid placing cpumasks on the stack, as
for large values of NR_CPUS these can consume significant amounts of
stack space and make stack overflows more likely.

- Both 2 arguments of cpumask_equal() is constant and free of change, no
  need to allocate extra cpumask variables.

- Merge cpumask_and(), cpumask_first() and cpumask_empty() into
  cpumask_first_and().

Reviewed-by: Sam Ravnborg <[email protected]>
Signed-off-by: Dawei Li <[email protected]>
Reviewed-by: Andreas Larsson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Andreas Larsson <[email protected]>

Author: Dawei Li

arch/sparc/kernel/irq_64.c

@@ -349,17 +349,13 @@ static unsigned int sun4u_compute_tid(unsigned long imap, unsigned long cpuid)
 #ifdef CONFIG_SMP
 static int irq_choose_cpu(unsigned int irq, const struct cpumask *affinity)
 {
-	cpumask_t mask;
 	int cpuid;
 
-	cpumask_copy(&mask, affinity);
-	if (cpumask_equal(&mask, cpu_online_mask)) {
+	if (cpumask_equal(affinity, cpu_online_mask)) {
 		cpuid = map_to_cpu(irq);
 	} else {
-		cpumask_t tmp;
-
-		cpumask_and(&tmp, cpu_online_mask, &mask);
-		cpuid = cpumask_empty(&tmp) ? map_to_cpu(irq) : cpumask_first(&tmp);
+		cpuid = cpumask_first_and(affinity, cpu_online_mask);
+		cpuid = cpuid < nr_cpu_ids ? cpuid : map_to_cpu(irq);
 	}
 
 	return cpuid;