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 # define do_raw_read_lock(rwlock)       do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)
  42 # define do_raw_read_lock_flags(lock, flags) \
  43                 do {__acquire(lock); arch_read_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  44 # define do_raw_read_trylock(rwlock)    arch_read_trylock(&(rwlock)->raw_lock)
  45 # define do_raw_read_unlock(rwlock)     do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  46 # define do_raw_write_lock(rwlock)      do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)
  47 # define do_raw_write_lock_flags(lock, flags) \
  48                 do {__acquire(lock); arch_write_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  49 # define do_raw_write_trylock(rwlock)   arch_write_trylock(&(rwlock)->raw_lock)
  50 # define do_raw_write_unlock(rwlock)    do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  51 #endif
  52
  53 #define read_can_lock(rwlock)           arch_read_can_lock(&(rwlock)->raw_lock)
  54 #define write_can_lock(rwlock)          arch_write_can_lock(&(rwlock)->raw_lock)
  55
  56 /*
  57  * Define the various rw_lock methods.  Note we define these
  58  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  59  * methods are defined as nops in the case they are not required.
  60  */
  61 #define read_trylock(lock)      __cond_lock(lock, _raw_read_trylock(lock))
  62 #define write_trylock(lock)     __cond_lock(lock, _raw_write_trylock(lock))
  63
  64 #define write_lock(lock)        _raw_write_lock(lock)
  65 #define read_lock(lock)         _raw_read_lock(lock)
  66
  67 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  68
  69 #define read_lock_irqsave(lock, flags)                  \
  70         do {                                            \
  71                 typecheck(unsigned long, flags);        \
  72                 flags = _raw_read_lock_irqsave(lock);   \
  73         } while (0)
  74 #define write_lock_irqsave(lock, flags)                 \
  75         do {                                            \
  76                 typecheck(unsigned long, flags);        \
  77                 flags = _raw_write_lock_irqsave(lock);  \
  78         } while (0)
  79
  80 #else
  81
  82 #define read_lock_irqsave(lock, flags)                  \
  83         do {                                            \
  84                 typecheck(unsigned long, flags);        \
  85                 _raw_read_lock_irqsave(lock, flags);    \
  86         } while (0)
  87 #define write_lock_irqsave(lock, flags)                 \
  88         do {                                            \
  89                 typecheck(unsigned long, flags);        \
  90                 _raw_write_lock_irqsave(lock, flags);   \
  91         } while (0)
  92
  93 #endif
  94
  95 #define read_lock_irq(lock)             _raw_read_lock_irq(lock)
  96 #define read_lock_bh(lock)              _raw_read_lock_bh(lock)
  97 #define write_lock_irq(lock)            _raw_write_lock_irq(lock)
  98 #define write_lock_bh(lock)             _raw_write_lock_bh(lock)
  99 #define read_unlock(lock)               _raw_read_unlock(lock)
 100 #define write_unlock(lock)              _raw_write_unlock(lock)
 101 #define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
 102 #define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
 103
 104 #define read_unlock_irqrestore(lock, flags)                     \
 105         do {                                                    \
 106                 typecheck(unsigned long, flags);                \
 107                 _raw_read_unlock_irqrestore(lock, flags);       \
 108         } while (0)
 109 #define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
 110
 111 #define write_unlock_irqrestore(lock, flags)            \
 112         do {                                            \
 113                 typecheck(unsigned long, flags);        \
 114                 _raw_write_unlock_irqrestore(lock, flags);      \
 115         } while (0)
 116 #define write_unlock_bh(lock)           _raw_write_unlock_bh(lock)
 117
 118 #define write_trylock_irqsave(lock, flags) \
 119 ({ \
 120         local_irq_save(flags); \
 121         write_trylock(lock) ? \
 122         1 : ({ local_irq_restore(flags); 0; }); \
 123 })
 124
 125 #endif /* __LINUX_RWLOCK_H */