1. 根目录:
2. include
3. linux
4. irqhandler.h

#ifndef _LINUX_IRQHANDLER_H
#define _LINUX_IRQHANDLER_H

/*
 * Interrupt flow handler typedefs are defined here to avoid circular
 * include dependencies.
 */

struct irq_desc;
struct irq_data;
typedef	void (*irq_flow_handler_t)(struct irq_desc *desc);
typedef	void (*irq_preflow_handler_t)(struct irq_data *data);

#endif