LXR linux/include/linux/smp

   1#ifndef __LINUX_SMPLOCK_H
   2#define __LINUX_SMPLOCK_H
   3
   4#ifdef CONFIG_LOCK_KERNEL
   5#include <linux/sched.h>
   6
   7#define kernel_locked()         (current->lock_depth >= 0)
   8
   9extern int __lockfunc __reacquire_kernel_lock(void);
  10extern void __lockfunc __release_kernel_lock(void);
  11
  12/*
  13 * Release/re-acquire global kernel lock for the scheduler
  14 */
  15#define release_kernel_lock(tsk) do {           \
  16        if (unlikely((tsk)->lock_depth >= 0))   \
  17                __release_kernel_lock();        \
  18} while (0)
  19
  20static inline int reacquire_kernel_lock(struct task_struct *task)
  21{
  22        if (unlikely(task->lock_depth >= 0))
  23                return __reacquire_kernel_lock();
  24        return 0;
  25}
  26
  27extern void __lockfunc
  28_lock_kernel(const char *func, const char *file, int line)
  29__acquires(kernel_lock);
  30
  31extern void __lockfunc
  32_unlock_kernel(const char *func, const char *file, int line)
  33__releases(kernel_lock);
  34
  35#define lock_kernel() do {                                      \
  36        _lock_kernel(__func__, __FILE__, __LINE__);             \
  37} while (0)
  38
  39#define unlock_kernel() do {                                    \
  40        _unlock_kernel(__func__, __FILE__, __LINE__);           \
  41} while (0)
  42
  43/*
  44 * Various legacy drivers don't really need the BKL in a specific
  45 * function, but they *do* need to know that the BKL became available.
  46 * This function just avoids wrapping a bunch of lock/unlock pairs
  47 * around code which doesn't really need it.
  48 */
  49static inline void cycle_kernel_lock(void)
  50{
  51        lock_kernel();
  52        unlock_kernel();
  53}
  54
  55#else
  56
  57#define lock_kernel()
  58#define unlock_kernel()
  59#define release_kernel_lock(task)               do { } while(0)
  60#define cycle_kernel_lock()                     do { } while(0)
  61#define reacquire_kernel_lock(task)             0
  62#define kernel_locked()                         1
  63
  64#endif /* CONFIG_LOCK_KERNEL */
  65#endif /* __LINUX_SMPLOCK_H */
  66