genirq/chip: Rework irq_set_handler() variants

Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.590753128@linutronix.de

Author: KAGA-KOKO

kernel/irq/chip.c

@@ -941,35 +941,23 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
 	}
 }
 
-void
-__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
-		  const char *name)
+void __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
+		       const char *name)
 {
-	unsigned long flags;
-	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
-
-	if (!desc)
-		return;
-
-	__irq_do_set_handler(desc, handle, is_chained, name);
-	irq_put_desc_busunlock(desc, flags);
+	scoped_irqdesc_get_and_lock(irq, 0)
+		__irq_do_set_handler(scoped_irqdesc, handle, is_chained, name);
 }
 EXPORT_SYMBOL_GPL(__irq_set_handler);
 
-void
-irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
-				 void *data)
+void irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+				      void *data)
 {
-	unsigned long flags;
-	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+	scoped_irqdesc_get_and_buslock(irq, 0) {
+		struct irq_desc *desc = scoped_irqdesc;
 
-	if (!desc)
-		return;
-
-	desc->irq_common_data.handler_data = data;
-	__irq_do_set_handler(desc, handle, 1, NULL);
-
-	irq_put_desc_busunlock(desc, flags);
+		desc->irq_common_data.handler_data = data;
+		__irq_do_set_handler(desc, handle, 1, NULL);
+	}
 }
 EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);