projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | #ifndef __LINUX_SMPLOCK_H |
| 2 | #define __LINUX_SMPLOCK_H | |
| 3 | ||
| f037360f | 4 | #ifdef CONFIG_LOCK_KERNEL |
| 1da177e4 LT |
5 | #include <linux/sched.h> |
| 6 | #include <linux/spinlock.h> | |
| 7 | ||
| 1da177e4 LT |
8 | #define kernel_locked() (current->lock_depth >= 0) |
| 9 | ||
| 10 | extern int __lockfunc __reacquire_kernel_lock(void); | |
| 11 | extern 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 | ||
| 33 | static 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 | ||
| 40 | extern void __lockfunc lock_kernel(void) __acquires(kernel_lock); | |
| 41 | extern 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 */ |