Merge branch 'docs-next' of git://git.lwn.net/linux-2.6
[linux-2.6/next.git] / include / linux / smp_lock.h
blob813be59bf3458785c00b3042645adb8a68a6b558
1 #ifndef __LINUX_SMPLOCK_H
2 #define __LINUX_SMPLOCK_H
4 #ifdef CONFIG_LOCK_KERNEL
5 #include <linux/sched.h>
7 #define kernel_locked() (current->lock_depth >= 0)
9 extern int __lockfunc __reacquire_kernel_lock(void);
10 extern void __lockfunc __release_kernel_lock(void);
13 * Release/re-acquire global kernel lock for the scheduler
15 #define release_kernel_lock(tsk) do { \
16 if (unlikely((tsk)->lock_depth >= 0)) \
17 __release_kernel_lock(); \
18 } while (0)
20 static inline int reacquire_kernel_lock(struct task_struct *task)
22 if (unlikely(task->lock_depth >= 0))
23 return __reacquire_kernel_lock();
24 return 0;
27 extern void __lockfunc lock_kernel(void) __acquires(kernel_lock);
28 extern void __lockfunc unlock_kernel(void) __releases(kernel_lock);
31 * Various legacy drivers don't really need the BKL in a specific
32 * function, but they *do* need to know that the BKL became available.
33 * This function just avoids wrapping a bunch of lock/unlock pairs
34 * around code which doesn't really need it.
36 static inline void cycle_kernel_lock(void)
38 lock_kernel();
39 unlock_kernel();
42 #else
44 #define lock_kernel() do { } while(0)
45 #define unlock_kernel() do { } while(0)
46 #define release_kernel_lock(task) do { } while(0)
47 #define cycle_kernel_lock() do { } while(0)
48 #define reacquire_kernel_lock(task) 0
49 #define kernel_locked() 1
51 #endif /* CONFIG_LOCK_KERNEL */
52 #endif /* __LINUX_SMPLOCK_H */