include/linux/locks.h

   1 #ifndef _LINUX_LOCKS_H
   2 #define _LINUX_LOCKS_H
   3
   4 #ifndef _LINUX_MM_H
   5 #include <linux/mm.h>
   6 #endif
   7 #ifndef _LINUX_PAGEMAP_H
   8 #include <linux/pagemap.h>
   9 #endif
  10
  11 /*
  12  * Buffer cache locking - note that interrupts may only unlock, not
  13  * lock buffers.
  14  */
  15 extern void __wait_on_buffer(struct buffer_head *);
  16
  17 extern inline void wait_on_buffer(struct buffer_head * bh)
  18 {
  19         if (test_bit(BH_Lock, &bh->b_state))
  20                 __wait_on_buffer(bh);
  21 }
  22
  23 extern inline void lock_buffer(struct buffer_head * bh)
  24 {
  25         while (test_and_set_bit(BH_Lock, &bh->b_state))
  26                 __wait_on_buffer(bh);
  27 }
  28
  29 extern inline void unlock_buffer(struct buffer_head *bh)
  30 {
  31         clear_bit(BH_Lock, &bh->b_state);
  32         wake_up(&bh->b_wait);
  33 }
  34
  35 /*
  36  * super-block locking. Again, interrupts may only unlock
  37  * a super-block (although even this isn't done right now.
  38  * nfs may need it).
  39  */
  40 extern void __wait_on_super(struct super_block *);
  41
  42 extern inline void wait_on_super(struct super_block * sb)
  43 {
  44         if (sb->s_lock)
  45                 __wait_on_super(sb);
  46 }
  47
  48 extern inline void lock_super(struct super_block * sb)
  49 {
  50         if (sb->s_lock)
  51                 __wait_on_super(sb);
  52         sb->s_lock = 1;
  53 }
  54
  55 extern inline void unlock_super(struct super_block * sb)
  56 {
  57         sb->s_lock = 0;
  58         wake_up(&sb->s_wait);
  59 }
  60
  61 #endif /* _LINUX_LOCKS_H */
  62