genirq: Introduce struct irq_common_data to host shared irq data

With the introduction of hierarchy irqdomain, struct irq_data becomes
per-chip instead of per-irq and there may be multiple irq_datas
associated with the same irq. Some per-irq data stored in struct
irq_data now may get duplicated into multiple irq_datas, and causes
inconsistent view.

So introduce struct irq_common_data to host per-irq common data and to
achieve consistent view among irq_chips.

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: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1433145945-789-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index a113a8d..c52d148 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -17,7 +17,7 @@
 
 /**
  * struct irq_desc - interrupt descriptor
- * @irq_data:		per irq and chip data passed down to chip functions
+ * @irq_common_data:	per irq and chip data passed down to chip functions
  * @kstat_irqs:		irq stats per cpu
  * @handle_irq:		highlevel irq-events handler
  * @preflow_handler:	handler called before the flow handler (currently used by sparc)
@@ -47,6 +47,7 @@
  * @name:		flow handler name for /proc/interrupts output
  */
 struct irq_desc {
+	struct irq_common_data	irq_common_data;
 	struct irq_data		irq_data;
 	unsigned int __percpu	*kstat_irqs;
 	irq_flow_handler_t	handle_irq;