x86, irq: Introduce helpers to access struct irq_cfg

Change irq_cfg() from static to extern, also introduce helper function
irqd_cfg(). Later we can rewrite these two helpers when enabling
hierarchy irqdomain.
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.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>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Grant Likely <grant.likely@linaro.org>
Link: http://lkml.kernel.org/r/1414397531-28254-9-git-send-email-jiang.liu@linux.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/hw_irq.h

@@ -132,6 +132,8 @@ struct irq_cfg {
 	};
 };
 
+extern struct irq_cfg *irq_cfg(unsigned int irq);
+extern struct irq_cfg *irqd_cfg(struct irq_data *irq_data);
 extern void setup_vector_irq(int cpu);
 extern int assign_irq_vector(int, struct irq_cfg *, const struct cpumask *);
 #ifdef CONFIG_SMP

arch/x86/kernel/apic/io_apic.c

@@ -281,11 +281,16 @@ int __init arch_early_irq_init(void)
 	return 0;
 }
 
-static inline struct irq_cfg *irq_cfg(unsigned int irq)
+struct irq_cfg *irq_cfg(unsigned int irq)
 {
 	return irq_get_chip_data(irq);
 }
 
+struct irq_cfg *irqd_cfg(struct irq_data *irq_data)
+{
+	return irq_data->chip_data;
+}
+
 static struct irq_cfg *alloc_irq_cfg(unsigned int irq, int node)
 {
 	struct irq_cfg *cfg;