include/linux/spinlock.h

   1 #ifndef __LINUX_SPINLOCK_H
   2 #define __LINUX_SPINLOCK_H
   3
   4 /*
   5  * include/linux/spinlock.h - generic spinlock/rwlock declarations
   6  *
   7  * here's the role of the various spinlock/rwlock related include files:
   8  *
   9  * on SMP builds:
  10  *
  11  *  asm/spinlock_types.h: contains the arch_spinlock_t/raw_rwlock_t and the
  12  *                        initializers
  13  *
  14  *  linux/spinlock_types.h:
  15  *                        defines the generic type and initializers
  16  *
  17  *  asm/spinlock.h:       contains the __raw_spin_*()/etc. lowlevel
  18  *                        implementations, mostly inline assembly code
  19  *
  20  *   (also included on UP-debug builds:)
  21  *
  22  *  linux/spinlock_api_smp.h:
  23  *                        contains the prototypes for the _spin_*() APIs.
  24  *
  25  *  linux/spinlock.h:     builds the final spin_*() APIs.
  26  *
  27  * on UP builds:
  28  *
  29  *  linux/spinlock_type_up.h:
  30  *                        contains the generic, simplified UP spinlock type.
  31  *                        (which is an empty structure on non-debug builds)
  32  *
  33  *  linux/spinlock_types.h:
  34  *                        defines the generic type and initializers
  35  *
  36  *  linux/spinlock_up.h:
  37  *                        contains the __raw_spin_*()/etc. version of UP
  38  *                        builds. (which are NOPs on non-debug, non-preempt
  39  *                        builds)
  40  *
  41  *   (included on UP-non-debug builds:)
  42  *
  43  *  linux/spinlock_api_up.h:
  44  *                        builds the _spin_*() APIs.
  45  *
  46  *  linux/spinlock.h:     builds the final spin_*() APIs.
  47  */
  48
  49 #include <linux/typecheck.h>
  50 #include <linux/preempt.h>
  51 #include <linux/linkage.h>
  52 #include <linux/compiler.h>
  53 #include <linux/thread_info.h>
  54 #include <linux/kernel.h>
  55 #include <linux/stringify.h>
  56 #include <linux/bottom_half.h>
  57
  58 #include <asm/system.h>
  59
  60 /*
  61  * Must define these before including other files, inline functions need them
  62  */
  63 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
  64
  65 #define LOCK_SECTION_START(extra)               \
  66         ".subsection 1\n\t"                     \
  67         extra                                   \
  68         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  69         LOCK_SECTION_NAME ":\n\t"               \
  70         ".endif\n"
  71
  72 #define LOCK_SECTION_END                        \
  73         ".previous\n\t"
  74
  75 #define __lockfunc __attribute__((section(".spinlock.text")))
  76
  77 /*
  78  * Pull the arch_spinlock_t and raw_rwlock_t definitions:
  79  */
  80 #include <linux/spinlock_types.h>
  81
  82 /*
  83  * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
  84  */
  85 #ifdef CONFIG_SMP
  86 # include <asm/spinlock.h>
  87 #else
  88 # include <linux/spinlock_up.h>
  89 #endif
  90
  91 #ifdef CONFIG_DEBUG_SPINLOCK
  92   extern void __spin_lock_init(spinlock_t *lock, const char *name,
  93                                struct lock_class_key *key);
  94 # define spin_lock_init(lock)                                   \
  95 do {                                                            \
  96         static struct lock_class_key __key;                     \
  97                                                                 \
  98         __spin_lock_init((lock), #lock, &__key);                \
  99 } while (0)
 100
 101 #else
 102 # define spin_lock_init(lock)                                   \
 103         do { *(lock) = __SPIN_LOCK_UNLOCKED(lock); } while (0)
 104 #endif
 105
 106 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
 107
 108 #ifdef CONFIG_GENERIC_LOCKBREAK
 109 #define spin_is_contended(lock) ((lock)->break_lock)
 110 #else
 111
 112 #ifdef __raw_spin_is_contended
 113 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
 114 #else
 115 #define spin_is_contended(lock) (((void)(lock), 0))
 116 #endif /*__raw_spin_is_contended*/
 117 #endif
 118
 119 /* The lock does not imply full memory barrier. */
 120 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 121 static inline void smp_mb__after_lock(void) { smp_mb(); }
 122 #endif
 123
 124 /**
 125  * spin_unlock_wait - wait until the spinlock gets unlocked
 126  * @lock: the spinlock in question.
 127  */
 128 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
 129
 130 #ifdef CONFIG_DEBUG_SPINLOCK
 131  extern void _raw_spin_lock(spinlock_t *lock);
 132 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 133  extern int _raw_spin_trylock(spinlock_t *lock);
 134  extern void _raw_spin_unlock(spinlock_t *lock);
 135 #else
 136 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
 137 # define _raw_spin_lock_flags(lock, flags) \
 138                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 139 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
 140 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
 141 #endif
 142
 143 /*
 144  * Define the various spin_lock methods.  Note we define these
 145  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 146  * various methods are defined as nops in the case they are not
 147  * required.
 148  */
 149 #define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
 150
 151 #define spin_lock(lock)                 _spin_lock(lock)
 152
 153 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 154 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 155 # define spin_lock_nest_lock(lock, nest_lock)                           \
 156          do {                                                           \
 157                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 158                  _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
 159          } while (0)
 160 #else
 161 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
 162 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 163 #endif
 164
 165 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 166
 167 #define spin_lock_irqsave(lock, flags)                  \
 168         do {                                            \
 169                 typecheck(unsigned long, flags);        \
 170                 flags = _spin_lock_irqsave(lock);       \
 171         } while (0)
 172
 173 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 174 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 175         do {                                                            \
 176                 typecheck(unsigned long, flags);                        \
 177                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
 178         } while (0)
 179 #else
 180 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 181         do {                                                            \
 182                 typecheck(unsigned long, flags);                        \
 183                 flags = _spin_lock_irqsave(lock);                       \
 184         } while (0)
 185 #endif
 186
 187 #else
 188
 189 #define spin_lock_irqsave(lock, flags)                  \
 190         do {                                            \
 191                 typecheck(unsigned long, flags);        \
 192                 _spin_lock_irqsave(lock, flags);        \
 193         } while (0)
 194
 195 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 196         spin_lock_irqsave(lock, flags)
 197
 198 #endif
 199
 200 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
 201 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
 202 #define spin_unlock(lock)               _spin_unlock(lock)
 203 #define spin_unlock_irq(lock)           _spin_unlock_irq(lock)
 204
 205 #define spin_unlock_irqrestore(lock, flags)             \
 206         do {                                            \
 207                 typecheck(unsigned long, flags);        \
 208                 _spin_unlock_irqrestore(lock, flags);   \
 209         } while (0)
 210 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
 211
 212 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
 213
 214 #define spin_trylock_irq(lock) \
 215 ({ \
 216         local_irq_disable(); \
 217         spin_trylock(lock) ? \
 218         1 : ({ local_irq_enable(); 0;  }); \
 219 })
 220
 221 #define spin_trylock_irqsave(lock, flags) \
 222 ({ \
 223         local_irq_save(flags); \
 224         spin_trylock(lock) ? \
 225         1 : ({ local_irq_restore(flags); 0; }); \
 226 })
 227
 228 /*
 229  * Pull the atomic_t declaration:
 230  * (asm-mips/atomic.h needs above definitions)
 231  */
 232 #include <asm/atomic.h>
 233 /**
 234  * atomic_dec_and_lock - lock on reaching reference count zero
 235  * @atomic: the atomic counter
 236  * @lock: the spinlock in question
 237  *
 238  * Decrements @atomic by 1.  If the result is 0, returns true and locks
 239  * @lock.  Returns false for all other cases.
 240  */
 241 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 242 #define atomic_dec_and_lock(atomic, lock) \
 243                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 244
 245 /**
 246  * spin_can_lock - would spin_trylock() succeed?
 247  * @lock: the spinlock in question.
 248  */
 249 #define spin_can_lock(lock)     (!spin_is_locked(lock))
 250
 251 /* Include rwlock functions */
 252 #include <linux/rwlock.h>
 253
 254 /*
 255  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 256  */
 257 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 258 # include <linux/spinlock_api_smp.h>
 259 #else
 260 # include <linux/spinlock_api_up.h>
 261 #endif
 262
 263 #endif /* __LINUX_SPINLOCK_H */