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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef __LINUX_SMPLOCK_H
2#define __LINUX_SMPLOCK_H
3
Al Virof0373602005-11-13 16:06:57 -08004#ifdef CONFIG_LOCK_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07005#include <linux/sched.h>
6#include <linux/spinlock.h>
7
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#define kernel_locked() (current->lock_depth >= 0)
9
10extern int __lockfunc __reacquire_kernel_lock(void);
11extern void __lockfunc __release_kernel_lock(void);
12
13/*
14 * Release/re-acquire global kernel lock for the scheduler
15 */
16#define release_kernel_lock(tsk) do { \
17 if (unlikely((tsk)->lock_depth >= 0)) \
18 __release_kernel_lock(); \
19} while (0)
20
21/*
22 * Non-SMP kernels will never block on the kernel lock,
23 * so we are better off returning a constant zero from
24 * reacquire_kernel_lock() so that the compiler can see
25 * it at compile-time.
26 */
27#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_BKL)
28# define return_value_on_smp return
29#else
30# define return_value_on_smp
31#endif
32
33static inline int reacquire_kernel_lock(struct task_struct *task)
34{
35 if (unlikely(task->lock_depth >= 0))
36 return_value_on_smp __reacquire_kernel_lock();
37 return 0;
38}
39
40extern void __lockfunc lock_kernel(void) __acquires(kernel_lock);
41extern void __lockfunc unlock_kernel(void) __releases(kernel_lock);
42
43#else
44
45#define lock_kernel() do { } while(0)
46#define unlock_kernel() do { } while(0)
47#define release_kernel_lock(task) do { } while(0)
48#define reacquire_kernel_lock(task) 0
49#define kernel_locked() 1
50
51#endif /* CONFIG_LOCK_KERNEL */
52#endif /* __LINUX_SMPLOCK_H */