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