src/add-ons/kernel/file_systems/googlefs/lock.h

   1 /*
   2         Copyright 1999, Be Incorporated.   All Rights Reserved.
   3         This file may be used under the terms of the Be Sample Code License.
   4 */
   5
   6 #ifndef _LOCK_H
   7 #define _LOCK_H
   8
   9 #include <BeBuild.h>
  10
  11 #include <OS.h>
  12
  13 typedef struct lock lock;
  14 typedef struct mlock mlock;
  15
  16 struct lock {
  17         sem_id          s;
  18         long            c;
  19 };
  20
  21 struct mlock {
  22         sem_id          s;
  23 };
  24
  25 extern _IMPEXP_KERNEL int       new_lock(lock *l, const char *name);
  26 extern _IMPEXP_KERNEL int       free_lock(lock *l);
  27
  28 static inline status_t LOCK(lock *l)
  29 {
  30         if (atomic_add(&(l->c), -1) <= 0)
  31                 return acquire_sem(l->s);
  32         return B_OK;
  33 }
  34
  35 static inline status_t UNLOCK(lock *l)
  36 {
  37         if (atomic_add(&(l->c), 1) < 0)
  38                 return release_sem(l->s);
  39         return B_OK;
  40 }
  41
  42
  43 //#define       LOCK(l)         if (atomic_add(&l.c, -1) <= 0) acquire_sem(l.s);
  44 //#define       UNLOCK(l)       if (atomic_add(&l.c, 1) < 0) release_sem(l.s);
  45
  46 extern _IMPEXP_KERNEL int       new_mlock(mlock *l, long c, const char *name);
  47 extern _IMPEXP_KERNEL int       free_mlock(mlock *l);
  48
  49 #define         LOCKM(l,cnt)    acquire_sem_etc(l.s, cnt, 0, 0)
  50 #define         UNLOCKM(l,cnt)  release_sem_etc(l.s, cnt, 0)
  51
  52 #endif