include/linux/rwlock.h

   1 #ifndef __LINUX_RWLOCK_H
   2 #define __LINUX_RWLOCK_H
   3
   4 #ifndef __LINUX_SPINLOCK_H
   5 # error "please don't include this file directly"
   6 #endif
   7
   8 /*
   9  * rwlock related methods
  10  *
  11  * split out from spinlock.h
  12  *
  13  * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
  14  * Released under the General Public License (GPL).
  15  */
  16
  17 #ifdef CONFIG_DEBUG_SPINLOCK
  18   extern void __rwlock_init(rwlock_t *lock, const char *name,
  19                             struct lock_class_key *key);
  20 # define rwlock_init(lock)                                      \
  21 do {                                                            \
  22         static struct lock_class_key __key;                     \
  23                                                                 \
  24         __rwlock_init((lock), #lock, &__key);                   \
  25 } while (0)
  26 #else
  27 # define rwlock_init(lock)                                      \
  28         do { *(lock) = __RW_LOCK_UNLOCKED(lock); } while (0)
  29 #endif
  30
  31 #ifdef CONFIG_DEBUG_SPINLOCK
  32  extern void do_raw_read_lock(rwlock_t *lock) __acquires(lock);
  33 #define do_raw_read_lock_flags(lock, flags) do_raw_read_lock(lock)
  34  extern int do_raw_read_trylock(rwlock_t *lock);
  35  extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock);
  36  extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock);
  37 #define do_raw_write_lock_flags(lock, flags) do_raw_write_lock(lock)
  38  extern int do_raw_write_trylock(rwlock_t *lock);
  39  extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock);
  40 #else
  41
  42 #ifndef arch_read_lock_flags
  43 # define arch_read_lock_flags(lock, flags)      arch_read_lock(lock)
  44 #endif
  45
  46 #ifndef arch_write_lock_flags
  47 # define arch_write_lock_flags(lock, flags)     arch_write_lock(lock)
  48 #endif
  49
  50 # define do_raw_read_lock(rwlock)       do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)
  51 # define do_raw_read_lock_flags(lock, flags) \
  52                 do {__acquire(lock); arch_read_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  53 # define do_raw_read_trylock(rwlock)    arch_read_trylock(&(rwlock)->raw_lock)
  54 # define do_raw_read_unlock(rwlock)     do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  55 # define do_raw_write_lock(rwlock)      do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)
  56 # define do_raw_write_lock_flags(lock, flags) \
  57                 do {__acquire(lock); arch_write_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  58 # define do_raw_write_trylock(rwlock)   arch_write_trylock(&(rwlock)->raw_lock)
  59 # define do_raw_write_unlock(rwlock)    do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  60 #endif
  61
  62 /*
  63  * Define the various rw_lock methods.  Note we define these
  64  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  65  * methods are defined as nops in the case they are not required.
  66  */
  67 #define read_trylock(lock)      __cond_lock(lock, _raw_read_trylock(lock))
  68 #define write_trylock(lock)     __cond_lock(lock, _raw_write_trylock(lock))
  69
  70 #define write_lock(lock)        _raw_write_lock(lock)
  71 #define read_lock(lock)         _raw_read_lock(lock)
  72
  73 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  74
  75 #define read_lock_irqsave(lock, flags)                  \
  76         do {                                            \
  77                 typecheck(unsigned long, flags);        \
  78                 flags = _raw_read_lock_irqsave(lock);   \
  79         } while (0)
  80 #define write_lock_irqsave(lock, flags)                 \
  81         do {                                            \
  82                 typecheck(unsigned long, flags);        \
  83                 flags = _raw_write_lock_irqsave(lock);  \
  84         } while (0)
  85
  86 #else
  87
  88 #define read_lock_irqsave(lock, flags)                  \
  89         do {                                            \
  90                 typecheck(unsigned long, flags);        \
  91                 _raw_read_lock_irqsave(lock, flags);    \
  92         } while (0)
  93 #define write_lock_irqsave(lock, flags)                 \
  94         do {                                            \
  95                 typecheck(unsigned long, flags);        \
  96                 _raw_write_lock_irqsave(lock, flags);   \
  97         } while (0)
  98
  99 #endif
 100
 101 #define read_lock_irq(lock)             _raw_read_lock_irq(lock)
 102 #define read_lock_bh(lock)              _raw_read_lock_bh(lock)
 103 #define write_lock_irq(lock)            _raw_write_lock_irq(lock)
 104 #define write_lock_bh(lock)             _raw_write_lock_bh(lock)
 105 #define read_unlock(lock)               _raw_read_unlock(lock)
 106 #define write_unlock(lock)              _raw_write_unlock(lock)
 107 #define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
 108 #define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
 109
 110 #define read_unlock_irqrestore(lock, flags)                     \
 111         do {                                                    \
 112                 typecheck(unsigned long, flags);                \
 113                 _raw_read_unlock_irqrestore(lock, flags);       \
 114         } while (0)
 115 #define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
 116
 117 #define write_unlock_irqrestore(lock, flags)            \
 118         do {                                            \
 119                 typecheck(unsigned long, flags);        \
 120                 _raw_write_unlock_irqrestore(lock, flags);      \
 121         } while (0)
 122 #define write_unlock_bh(lock)           _raw_write_unlock_bh(lock)
 123
 124 #define write_trylock_irqsave(lock, flags) \
 125 ({ \
 126         local_irq_save(flags); \
 127         write_trylock(lock) ? \
 128         1 : ({ local_irq_restore(flags); 0; }); \
 129 })
 130
 131 #ifdef arch_rwlock_is_contended
 132 #define rwlock_is_contended(lock) \
 133          arch_rwlock_is_contended(&(lock)->raw_lock)
 134 #else
 135 #define rwlock_is_contended(lock)       ((void)(lock), 0)
 136 #endif /* arch_rwlock_is_contended */
 137
 138 #endif /* __LINUX_RWLOCK_H */