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

#ifndef _LINUX_BH_H
#define _LINUX_BH_H

#include <linux/preempt.h>
#include <linux/preempt_mask.h>

#ifdef CONFIG_TRACE_IRQFLAGS
extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
#else
static __always_inline void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
	preempt_count_add(cnt);
	barrier();
}
#endif

static inline void local_bh_disable(void)
{
	__local_bh_disable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
}

extern void _local_bh_enable(void);
extern void __local_bh_enable_ip(unsigned long ip, unsigned int cnt);

static inline void local_bh_enable_ip(unsigned long ip)
{
	__local_bh_enable_ip(ip, SOFTIRQ_DISABLE_OFFSET);
}

static inline void local_bh_enable(void)
{
	__local_bh_enable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
}

#endif /* _LINUX_BH_H */