genirq: Move irq_has_action() into core code

This function uses irq_to_desc() and is going to be used by modules to
replace the open coded irq_to_desc() (ab)usage. The final goal is to remove
the export of irq_to_desc() so driver cannot fiddle with it anymore.

Move it into the core code and fixup the usage sites to include the proper
header.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201210194042.548936472@linutronix.de

arch/alpha/kernel/sys_jensen.c

@@ -7,7 +7,7 @@
  *
  * Code supporting the Jensen.
  */
-
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/mm.h>

arch/x86/kernel/topology.c

@@ -25,6 +25,7 @@
  *
  * Send feedback to <colpatch@us.ibm.com>
  */
+#include <linux/interrupt.h>
 #include <linux/nodemask.h>
 #include <linux/export.h>
 #include <linux/mmzone.h>

include/linux/interrupt.h

@@ -232,6 +232,7 @@ extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
 # define local_irq_enable_in_hardirq()	local_irq_enable()
 #endif
 
+bool irq_has_action(unsigned int irq);
 extern void disable_irq_nosync(unsigned int irq);
 extern bool disable_hardirq(unsigned int irq);
 extern void disable_irq(unsigned int irq);

include/linux/irqdesc.h

@@ -179,12 +179,7 @@ int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq,
 /* Test to see if a driver has successfully requested an irq */
 static inline int irq_desc_has_action(struct irq_desc *desc)
 {
-	return desc->action != NULL;
-}
-
-static inline int irq_has_action(unsigned int irq)
-{
-	return irq_desc_has_action(irq_to_desc(irq));
+	return desc && desc->action != NULL;
 }
 
 /**

kernel/irq/manage.c

@@ -2822,3 +2822,20 @@ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
 	return err;
 }
 EXPORT_SYMBOL_GPL(irq_set_irqchip_state);
+
+/**
+ * irq_has_action - Check whether an interrupt is requested
+ * @irq:	The linux irq number
+ *
+ * Returns: A snapshot of the current state
+ */
+bool irq_has_action(unsigned int irq)
+{
+	bool res;
+
+	rcu_read_lock();
+	res = irq_desc_has_action(irq_to_desc(irq));
+	rcu_read_unlock();
+	return res;
+}
+EXPORT_SYMBOL_GPL(irq_has_action);