mach/lock-intern.h

   1 /* Copyright (C) 1994, 1996, 2007 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _LOCK_INTERN_H
  20 #define _LOCK_INTERN_H
  21
  22 #include <sys/cdefs.h>
  23 #include <machine-lock.h>
  24
  25 #ifndef _EXTERN_INLINE
  26 #define _EXTERN_INLINE __extern_inline
  27 #endif
  28
  29
  30 /* Initialize LOCK.  */
  31
  32 _EXTERN_INLINE void
  33 __spin_lock_init (__spin_lock_t *__lock)
  34 {
  35   *__lock = __SPIN_LOCK_INITIALIZER;
  36 }
  37
  38
  39 /* Lock LOCK, blocking if we can't get it.  */
  40 extern void __spin_lock_solid (__spin_lock_t *__lock);
  41
  42 /* Lock the spin lock LOCK.  */
  43
  44 _EXTERN_INLINE void
  45 __spin_lock (__spin_lock_t *__lock)
  46 {
  47   if (! __spin_try_lock (__lock))
  48     __spin_lock_solid (__lock);
  49 }
  50 \f
  51 /* Name space-clean internal interface to mutex locks.
  52
  53    Code internal to the C library uses these functions to lock and unlock
  54    mutex locks.  These locks are of type `struct mutex', defined in
  55    <cthreads.h>.  The functions here are name space-clean.  If the program
  56    is linked with the cthreads library, `__mutex_lock_solid' and
  57    `__mutex_unlock_solid' will invoke the corresponding cthreads functions
  58    to implement real mutex locks.  If not, simple stub versions just use
  59    spin locks.  */
  60
  61
  62 /* Initialize the newly allocated mutex lock LOCK for further use.  */
  63 extern void __mutex_init (void *__lock);
  64
  65 /* Lock LOCK, blocking if we can't get it.  */
  66 extern void __mutex_lock_solid (void *__lock);
  67
  68 /* Finish unlocking LOCK, after the spin lock LOCK->held has already been
  69    unlocked.  This function will wake up any thread waiting on LOCK.  */
  70 extern void __mutex_unlock_solid (void *__lock);
  71
  72 /* Lock the mutex lock LOCK.  */
  73
  74 _EXTERN_INLINE void
  75 __mutex_lock (void *__lock)
  76 {
  77   if (! __spin_try_lock ((__spin_lock_t *) __lock))
  78     __mutex_lock_solid (__lock);
  79 }
  80
  81 /* Unlock the mutex lock LOCK.  */
  82
  83 _EXTERN_INLINE void
  84 __mutex_unlock (void *__lock)
  85 {
  86   __spin_unlock ((__spin_lock_t *) __lock);
  87   __mutex_unlock_solid (__lock);
  88 }
  89
  90
  91 _EXTERN_INLINE int
  92 __mutex_trylock (void *__lock)
  93 {
  94   return __spin_try_lock ((__spin_lock_t *) __lock);
  95 }
  96
  97 #endif /* lock-intern.h */