x86, irq: Simplify arch_early_irq_init()

Simplify function arch_early_irq_init() and kill static array irq_cfgx[].
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1402302011-23642-21-git-send-email-jiang.liu@linux.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apic/io_apic.c

@@ -183,6 +183,7 @@ early_param("noapic", parse_noapic);
 
 static int io_apic_setup_irq_pin(unsigned int irq, int node,
 				 struct io_apic_irq_attr *attr);
+static struct irq_cfg *alloc_irq_and_cfg_at(unsigned int at, int node);
 
 /* Will be called in mpparse/acpi/sfi codes for saving IRQ info */
 void mp_save_irq(struct mpc_intsrc *m)
@@ -214,14 +215,10 @@ static struct irq_pin_list *alloc_irq_pin_list(int node)
 	return kzalloc_node(sizeof(struct irq_pin_list), GFP_KERNEL, node);
 }
 
-
-/* irq_cfg is indexed by the sum of all RTEs in all I/O APICs. */
-static struct irq_cfg irq_cfgx[NR_IRQS_LEGACY];
-
 int __init arch_early_irq_init(void)
 {
 	struct irq_cfg *cfg;
-	int count, node, i;
+	int i, node = cpu_to_node(0);
 
 	if (!nr_legacy_irqs())
 		io_apic_irqs = ~0UL;
@@ -234,22 +231,14 @@ int __init arch_early_irq_init(void)
 			pr_err("IOAPIC %d: suspend/resume impossible!\n", i);
 	}
 
-	cfg = irq_cfgx;
-	count = ARRAY_SIZE(irq_cfgx);
-	node = cpu_to_node(0);
-
-	for (i = 0; i < count; i++) {
-		irq_set_chip_data(i, &cfg[i]);
-		zalloc_cpumask_var_node(&cfg[i].domain, GFP_KERNEL, node);
-		zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_KERNEL, node);
-		/*
-		 * For legacy IRQ's, start with assigning irq0 to irq15 to
-		 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
-		 */
-		if (i < nr_legacy_irqs()) {
-			cfg[i].vector = IRQ0_VECTOR + i;
-			cpumask_setall(cfg[i].domain);
-		}
+	/*
+	 * For legacy IRQ's, start with assigning irq0 to irq15 to
+	 * IRQ0_VECTOR to IRQ15_VECTOR for all cpu's.
+	 */
+	for (i = 0; i < nr_legacy_irqs(); i++) {
+		cfg = alloc_irq_and_cfg_at(i, node);
+		cfg->vector = IRQ0_VECTOR + i;
+		cpumask_setall(cfg->domain);
 	}
 
 	return 0;
@@ -3377,7 +3366,7 @@ int __init arch_probe_nr_irqs(void)
 	if (nr < nr_irqs)
 		nr_irqs = nr;
 
-	return nr_legacy_irqs();
+	return 0;
 }
 
 int io_apic_set_pci_routing(struct device *dev, int irq,