include/asm-generic/smplock.h

   1 /*
   2  * <asm/smplock.h>
   3  *
   4  * Default SMP lock implementation
   5  */
   6 #include <linux/interrupt.h>
   7 #include <linux/spinlock.h>
   8
   9 extern spinlock_t kernel_flag;
  10
  11 #define kernel_locked()         spin_is_locked(&kernel_flag)
  12
  13 /*
  14  * Release global kernel lock and global interrupt lock
  15  */
  16 #define release_kernel_lock(task, cpu) \
  17 do { \
  18         if (task->lock_depth >= 0) \
  19                 spin_unlock(&kernel_flag); \
  20         release_irqlock(cpu); \
  21         __sti(); \
  22 } while (0)
  23
  24 /*
  25  * Re-acquire the kernel lock
  26  */
  27 #define reacquire_kernel_lock(task) \
  28 do { \
  29         if (task->lock_depth >= 0) \
  30                 spin_lock(&kernel_flag); \
  31 } while (0)
  32
  33
  34 /*
  35  * Getting the big kernel lock.
  36  *
  37  * This cannot happen asynchronously,
  38  * so we only need to worry about other
  39  * CPU's.
  40  */
  41 extern __inline__ void lock_kernel(void)
  42 {
  43         if (!++current->lock_depth)
  44                 spin_lock(&kernel_flag);
  45 }
  46
  47 extern __inline__ void unlock_kernel(void)
  48 {
  49         if (--current->lock_depth < 0)
  50                 spin_unlock(&kernel_flag);
  51 }