aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/smp_lock.h
blob: 2ea1dd1ba21cedc1cdf7f9f0c74d939641d0e5b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
#ifndef __LINUX_SMPLOCK_H
#define __LINUX_SMPLOCK_H

#ifdef CONFIG_LOCK_KERNEL
#include <linux/sched.h>

#define kernel_locked()		(current->lock_depth >= 0)

extern int __lockfunc __reacquire_kernel_lock(void);
extern void __lockfunc __release_kernel_lock(void);

/*
 * Release/re-acquire global kernel lock for the scheduler
 */
#define release_kernel_lock(tsk) do { 		\
	if (unlikely((tsk)->lock_depth >= 0))	\
		__release_kernel_lock();	\
} while (0)

static inline int reacquire_kernel_lock(struct task_struct *task)
{
	if (unlikely(task->lock_depth >= 0))
		return __reacquire_kernel_lock();
	return 0;
}

extern void __lockfunc
_lock_kernel(const char *func, const char *file, int line)
__acquires(kernel_lock);

extern void __lockfunc
_unlock_kernel(const char *func, const char *file, int line)
__releases(kernel_lock);

#define lock_kernel() do {					\
	_lock_kernel(__func__, __FILE__, __LINE__);		\
} while (0)

#define unlock_kernel()	do {					\
	_unlock_kernel(__func__, __FILE__, __LINE__);		\
} while (0)

/*
 * Various legacy drivers don't really need the BKL in a specific
 * function, but they *do* need to know that the BKL became available.
 * This function just avoids wrapping a bunch of lock/unlock pairs
 * around code which doesn't really need it.
 */
static inline void cycle_kernel_lock(void)
{
	lock_kernel();
	unlock_kernel();
}

#else

#define lock_kernel()
#define unlock_kernel()
#define release_kernel_lock(task)		do { } while(0)
#define cycle_kernel_lock()			do { } while(0)
#define reacquire_kernel_lock(task)		0
#define kernel_locked()				1

#endif /* CONFIG_LOCK_KERNEL */
#endif /* __LINUX_SMPLOCK_H */