1 #ifndef __LINUX_SPINLOCK_H
2 #define __LINUX_SPINLOCK_H
5 * include/linux/spinlock.h - generic spinlock/rwlock declarations
7 * here's the role of the various spinlock/rwlock related include files:
11 * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
14 * linux/spinlock_types.h:
15 * defines the generic type and initializers
17 * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel
18 * implementations, mostly inline assembly code
20 * (also included on UP-debug builds:)
22 * linux/spinlock_api_smp.h:
23 * contains the prototypes for the _spin_*() APIs.
25 * linux/spinlock.h: builds the final spin_*() APIs.
29 * linux/spinlock_type_up.h:
30 * contains the generic, simplified UP spinlock type.
31 * (which is an empty structure on non-debug builds)
33 * linux/spinlock_types.h:
34 * defines the generic type and initializers
36 * linux/spinlock_up.h:
37 * contains the arch_spin_*()/etc. version of UP
38 * builds. (which are NOPs on non-debug, non-preempt
41 * (included on UP-non-debug builds:)
43 * linux/spinlock_api_up.h:
44 * builds the _spin_*() APIs.
46 * linux/spinlock.h: builds the final spin_*() APIs.
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>
58 #include <asm/system.h>
61 * Must define these before including other files, inline functions need them
63 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
65 #define LOCK_SECTION_START(extra) \
68 ".ifndef " LOCK_SECTION_NAME "\n\t" \
69 LOCK_SECTION_NAME ":\n\t" \
72 #define LOCK_SECTION_END \
75 #define __lockfunc __attribute__((section(".spinlock.text")))
78 * Pull the arch_spinlock_t and arch_rwlock_t definitions:
80 #include <linux/spinlock_types.h>
83 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
86 # include <asm/spinlock.h>
88 # include <linux/spinlock_up.h>
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) \
96 static struct lock_class_key __key; \
98 __spin_lock_init((lock), #lock, &__key); \
102 # define spin_lock_init(lock) \
103 do { *(lock) = __SPIN_LOCK_UNLOCKED(lock); } while (0)
106 #define spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock)
108 #ifdef CONFIG_GENERIC_LOCKBREAK
109 #define spin_is_contended(lock) ((lock)->break_lock)
112 #ifdef arch_spin_is_contended
113 #define spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock)
115 #define spin_is_contended(lock) (((void)(lock), 0))
116 #endif /*arch_spin_is_contended*/
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(); }
125 * spin_unlock_wait - wait until the spinlock gets unlocked
126 * @lock: the spinlock in question.
128 #define spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock)
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);
136 # define _raw_spin_lock(lock) arch_spin_lock(&(lock)->raw_lock)
137 # define _raw_spin_lock_flags(lock, flags) \
138 arch_spin_lock_flags(&(lock)->raw_lock, *(flags))
139 # define _raw_spin_trylock(lock) arch_spin_trylock(&(lock)->raw_lock)
140 # define _raw_spin_unlock(lock) arch_spin_unlock(&(lock)->raw_lock)
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
149 #define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock))
151 #define spin_lock(lock) _spin_lock(lock)
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) \
157 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
158 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
161 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
162 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
165 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
167 #define spin_lock_irqsave(lock, flags) \
169 typecheck(unsigned long, flags); \
170 flags = _spin_lock_irqsave(lock); \
173 #ifdef CONFIG_DEBUG_LOCK_ALLOC
174 #define spin_lock_irqsave_nested(lock, flags, subclass) \
176 typecheck(unsigned long, flags); \
177 flags = _spin_lock_irqsave_nested(lock, subclass); \
180 #define spin_lock_irqsave_nested(lock, flags, subclass) \
182 typecheck(unsigned long, flags); \
183 flags = _spin_lock_irqsave(lock); \
189 #define spin_lock_irqsave(lock, flags) \
191 typecheck(unsigned long, flags); \
192 _spin_lock_irqsave(lock, flags); \
195 #define spin_lock_irqsave_nested(lock, flags, subclass) \
196 spin_lock_irqsave(lock, flags)
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)
205 #define spin_unlock_irqrestore(lock, flags) \
207 typecheck(unsigned long, flags); \
208 _spin_unlock_irqrestore(lock, flags); \
210 #define spin_unlock_bh(lock) _spin_unlock_bh(lock)
212 #define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))
214 #define spin_trylock_irq(lock) \
216 local_irq_disable(); \
217 spin_trylock(lock) ? \
218 1 : ({ local_irq_enable(); 0; }); \
221 #define spin_trylock_irqsave(lock, flags) \
223 local_irq_save(flags); \
224 spin_trylock(lock) ? \
225 1 : ({ local_irq_restore(flags); 0; }); \
229 * Pull the atomic_t declaration:
230 * (asm-mips/atomic.h needs above definitions)
232 #include <asm/atomic.h>
234 * atomic_dec_and_lock - lock on reaching reference count zero
235 * @atomic: the atomic counter
236 * @lock: the spinlock in question
238 * Decrements @atomic by 1. If the result is 0, returns true and locks
239 * @lock. Returns false for all other cases.
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))
246 * spin_can_lock - would spin_trylock() succeed?
247 * @lock: the spinlock in question.
249 #define spin_can_lock(lock) (!spin_is_locked(lock))
251 /* Include rwlock functions */
252 #include <linux/rwlock.h>
255 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
257 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
258 # include <linux/spinlock_api_smp.h>
260 # include <linux/spinlock_api_up.h>
263 #endif /* __LINUX_SPINLOCK_H */