[PATCH v6 1/6] genirq: define an empty function set_handle_irq() if !GENERIC_IRQ_MULTI_HANDLER

[Zhen Lei <thunder.leizhen@huawei.com>]

To avoid compilation error if an irqchip driver references the function
set_handle_irq() but may not select GENERIC_IRQ_MULTI_HANDLER on some
systems.

For example, the Synopsys DesignWare APB interrupt controller
(dw_apb_ictl) is used as the secondary interrupt controller on arc, csky,
arm64, and most arm32 SoCs, and it's also used as the primary interrupt
controller on Hisilicon SD5203 (an arm32 SoC). The latter need to use
set_handle_irq() to register the top-level IRQ handler, but this multi
irq handler registration mechanism is not implemented on arc system.

The input parameter "handle_irq" maybe defined as static and only
set_handle_irq() references it. This will trigger "defined but not used"
warning. So add "(void)handle_irq" to suppress it.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 include/linux/irq.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 1b7f4dfee35b397..b167baef88c0b43 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -1252,6 +1252,12 @@ void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
  * top-level IRQ handler.
  */
 extern void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
+#else
+#define set_handle_irq(handle_irq)		\
+	do {					\
+		(void)handle_irq;		\
+		WARN_ON(1);			\
+	} while (0)
 #endif
 
 #endif /* _LINUX_IRQ_H */
-- 
1.8.3