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1da177e4 LT |
1 | #ifndef __LINUX_SMPLOCK_H |
2 | #define __LINUX_SMPLOCK_H | |
3 | ||
4 | #include <linux/config.h> | |
5 | #include <linux/sched.h> | |
6 | #include <linux/spinlock.h> | |
7 | ||
8 | #ifdef CONFIG_LOCK_KERNEL | |
9 | ||
10 | #define kernel_locked() (current->lock_depth >= 0) | |
11 | ||
12 | extern int __lockfunc __reacquire_kernel_lock(void); | |
13 | extern void __lockfunc __release_kernel_lock(void); | |
14 | ||
15 | /* | |
16 | * Release/re-acquire global kernel lock for the scheduler | |
17 | */ | |
18 | #define release_kernel_lock(tsk) do { \ | |
19 | if (unlikely((tsk)->lock_depth >= 0)) \ | |
20 | __release_kernel_lock(); \ | |
21 | } while (0) | |
22 | ||
23 | /* | |
24 | * Non-SMP kernels will never block on the kernel lock, | |
25 | * so we are better off returning a constant zero from | |
26 | * reacquire_kernel_lock() so that the compiler can see | |
27 | * it at compile-time. | |
28 | */ | |
29 | #if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_BKL) | |
30 | # define return_value_on_smp return | |
31 | #else | |
32 | # define return_value_on_smp | |
33 | #endif | |
34 | ||
35 | static inline int reacquire_kernel_lock(struct task_struct *task) | |
36 | { | |
37 | if (unlikely(task->lock_depth >= 0)) | |
38 | return_value_on_smp __reacquire_kernel_lock(); | |
39 | return 0; | |
40 | } | |
41 | ||
42 | extern void __lockfunc lock_kernel(void) __acquires(kernel_lock); | |
43 | extern void __lockfunc unlock_kernel(void) __releases(kernel_lock); | |
44 | ||
45 | #else | |
46 | ||
47 | #define lock_kernel() do { } while(0) | |
48 | #define unlock_kernel() do { } while(0) | |
49 | #define release_kernel_lock(task) do { } while(0) | |
50 | #define reacquire_kernel_lock(task) 0 | |
51 | #define kernel_locked() 1 | |
52 | ||
53 | #endif /* CONFIG_LOCK_KERNEL */ | |
54 | #endif /* __LINUX_SMPLOCK_H */ |