ia64: Validate online cpus in irq_set_affinity() callbacks

The [user space] interface does not filter out offline cpus. It merily
guarantees that the mask contains at least one online cpu.

So the selector in the irq chip implementation needs to make sure to
pick only an online cpu because otherwise:

Offline Core 1
Set affinity to 0xe (is valid due to online mask 0xd)
cpumask_first will pick core 1, which is offline

Signed-off-by: Thomas Gleixner <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Fenghua Yu <[e-mail]>
Cc: ia64 <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Thomas Gleixner <[e-mail]>

arch/ia64/kernel/msi_ia64.c

···
 {
 	struct msi_msg msg;
 	u32 addr, data;
-	int cpu = first_cpu(*cpu_mask);
+	int cpu = cpumask_first_and(cpu_mask, cpu_online_mask);
 	unsigned int irq = idata->irq;
-
-	if (!cpu_online(cpu))
-		return -1;
 
 	if (irq_prepare_move(irq, cpu))
 		return -1;
···
 	unsigned int irq = data->irq;
 	struct irq_cfg *cfg = irq_cfg + irq;
 	struct msi_msg msg;
-	int cpu = cpumask_first(mask);
-
-	if (!cpu_online(cpu))
-		return -1;
+	int cpu = cpumask_first_and(mask, cpu_online_mask);
 
 	if (irq_prepare_move(irq, cpu))
 		return -1;

arch/ia64/sn/kernel/irq.c

···
 	nasid_t nasid;
 	int slice;
 
-	nasid = cpuid_to_nasid(cpumask_first(mask));
-	slice = cpuid_to_slice(cpumask_first(mask));
+	nasid = cpuid_to_nasid(cpumask_first_and(mask, cpu_online_mask));
+	slice = cpuid_to_slice(cpumask_first_and(mask, cpu_online_mask));
 
 	list_for_each_entry_safe(sn_irq_info, sn_irq_info_safe,
 				 sn_irq_lh[irq], list)

arch/ia64/sn/kernel/msi_sn.c

···
 	struct sn_pcibus_provider *provider;
 	unsigned int cpu, irq = data->irq;
 
-	cpu = cpumask_first(cpu_mask);
+	cpu = cpumask_first_and(cpu_mask, cpu_online_mask);
 	sn_irq_info = sn_msi_info[irq].sn_irq_info;
 	if (sn_irq_info == NULL || sn_irq_info->irq_int_bit >= 0)
 		return -1;