1#ifndef __LINUX_SMPLOCK_H 2#define __LINUX_SMPLOCK_H 3 4#ifdef CONFIG_LOCK_KERNEL 5#include <linux/sched.h> 6#include <linux/spinlock.h> 7 8#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 */ 53