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#ifndef __LINUX_SMPLOCK_H
#define __LINUX_SMPLOCK_H
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
extern spinlock_t kernel_flag;
#define kernel_locked() (current->lock_depth >= 0)
#define get_kernel_lock() spin_lock(&kernel_flag)
#define put_kernel_lock() spin_unlock(&kernel_flag)
/*
* Release global kernel lock.
*/
static inline void release_kernel_lock(struct task_struct *task)
{
if (unlikely(task->lock_depth >= 0))
put_kernel_lock();
}
/*
* Re-acquire the kernel lock
*/
static inline void reacquire_kernel_lock(struct task_struct *task)
{
if (unlikely(task->lock_depth >= 0))
get_kernel_lock();
}
/*
* Getting the big kernel lock.
*
* This cannot happen asynchronously,
* so we only need to worry about other
* CPU's.
*/
static inline void lock_kernel(void)
{
int depth = current->lock_depth+1;
if (likely(!depth))
get_kernel_lock();
current->lock_depth = depth;
}
static inline void unlock_kernel(void)
{
if (unlikely(current->lock_depth < 0))
BUG();
if (likely(--current->lock_depth < 0))
put_kernel_lock();
}
#else
#define lock_kernel() do { } while(0)
#define unlock_kernel() do { } while(0)
#define release_kernel_lock(task) do { } while(0)
#define reacquire_kernel_lock(task) do { } while(0)
#define kernel_locked() 1
#endif /* CONFIG_SMP || CONFIG_PREEMPT */
#endif /* __LINUX_SMPLOCK_H */
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