sysfs: Remove support for tagged directories with untagged members (again)
[linux-btrfs-devel.git] / include / linux / spinlock.h
blob7df6c17b0281867241ffa64de8429f6ff84d5d17
1 #ifndef __LINUX_SPINLOCK_H
2 #define __LINUX_SPINLOCK_H
4 /*
5 * include/linux/spinlock.h - generic spinlock/rwlock declarations
7 * here's the role of the various spinlock/rwlock related include files:
9 * on SMP builds:
11 * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
12 * initializers
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.
27 * on UP builds:
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
39 * builds)
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/irqflags.h>
54 #include <linux/thread_info.h>
55 #include <linux/kernel.h>
56 #include <linux/stringify.h>
57 #include <linux/bottom_half.h>
59 #include <asm/system.h>
62 * Must define these before including other files, inline functions need them
64 #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
66 #define LOCK_SECTION_START(extra) \
67 ".subsection 1\n\t" \
68 extra \
69 ".ifndef " LOCK_SECTION_NAME "\n\t" \
70 LOCK_SECTION_NAME ":\n\t" \
71 ".endif\n"
73 #define LOCK_SECTION_END \
74 ".previous\n\t"
76 #define __lockfunc __attribute__((section(".spinlock.text")))
79 * Pull the arch_spinlock_t and arch_rwlock_t definitions:
81 #include <linux/spinlock_types.h>
84 * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
86 #ifdef CONFIG_SMP
87 # include <asm/spinlock.h>
88 #else
89 # include <linux/spinlock_up.h>
90 #endif
92 #ifdef CONFIG_DEBUG_SPINLOCK
93 extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
94 struct lock_class_key *key);
95 # define raw_spin_lock_init(lock) \
96 do { \
97 static struct lock_class_key __key; \
99 __raw_spin_lock_init((lock), #lock, &__key); \
100 } while (0)
102 #else
103 # define raw_spin_lock_init(lock) \
104 do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
105 #endif
107 #define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock)
109 #ifdef CONFIG_GENERIC_LOCKBREAK
110 #define raw_spin_is_contended(lock) ((lock)->break_lock)
111 #else
113 #ifdef arch_spin_is_contended
114 #define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock)
115 #else
116 #define raw_spin_is_contended(lock) (((void)(lock), 0))
117 #endif /*arch_spin_is_contended*/
118 #endif
120 /* The lock does not imply full memory barrier. */
121 #ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
122 static inline void smp_mb__after_lock(void) { smp_mb(); }
123 #endif
126 * raw_spin_unlock_wait - wait until the spinlock gets unlocked
127 * @lock: the spinlock in question.
129 #define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock)
131 #ifdef CONFIG_DEBUG_SPINLOCK
132 extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
133 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
134 extern int do_raw_spin_trylock(raw_spinlock_t *lock);
135 extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
136 #else
137 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
139 __acquire(lock);
140 arch_spin_lock(&lock->raw_lock);
143 static inline void
144 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
146 __acquire(lock);
147 arch_spin_lock_flags(&lock->raw_lock, *flags);
150 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
152 return arch_spin_trylock(&(lock)->raw_lock);
155 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
157 arch_spin_unlock(&lock->raw_lock);
158 __release(lock);
160 #endif
163 * Define the various spin_lock methods. Note we define these
164 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
165 * various methods are defined as nops in the case they are not
166 * required.
168 #define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock))
170 #define raw_spin_lock(lock) _raw_spin_lock(lock)
172 #ifdef CONFIG_DEBUG_LOCK_ALLOC
173 # define raw_spin_lock_nested(lock, subclass) \
174 _raw_spin_lock_nested(lock, subclass)
176 # define raw_spin_lock_nest_lock(lock, nest_lock) \
177 do { \
178 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
179 _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
180 } while (0)
181 #else
182 # define raw_spin_lock_nested(lock, subclass) _raw_spin_lock(lock)
183 # define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock)
184 #endif
186 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
188 #define raw_spin_lock_irqsave(lock, flags) \
189 do { \
190 typecheck(unsigned long, flags); \
191 flags = _raw_spin_lock_irqsave(lock); \
192 } while (0)
194 #ifdef CONFIG_DEBUG_LOCK_ALLOC
195 #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
196 do { \
197 typecheck(unsigned long, flags); \
198 flags = _raw_spin_lock_irqsave_nested(lock, subclass); \
199 } while (0)
200 #else
201 #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
202 do { \
203 typecheck(unsigned long, flags); \
204 flags = _raw_spin_lock_irqsave(lock); \
205 } while (0)
206 #endif
208 #else
210 #define raw_spin_lock_irqsave(lock, flags) \
211 do { \
212 typecheck(unsigned long, flags); \
213 _raw_spin_lock_irqsave(lock, flags); \
214 } while (0)
216 #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
217 raw_spin_lock_irqsave(lock, flags)
219 #endif
221 #define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock)
222 #define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock)
223 #define raw_spin_unlock(lock) _raw_spin_unlock(lock)
224 #define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock)
226 #define raw_spin_unlock_irqrestore(lock, flags) \
227 do { \
228 typecheck(unsigned long, flags); \
229 _raw_spin_unlock_irqrestore(lock, flags); \
230 } while (0)
231 #define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock)
233 #define raw_spin_trylock_bh(lock) \
234 __cond_lock(lock, _raw_spin_trylock_bh(lock))
236 #define raw_spin_trylock_irq(lock) \
237 ({ \
238 local_irq_disable(); \
239 raw_spin_trylock(lock) ? \
240 1 : ({ local_irq_enable(); 0; }); \
243 #define raw_spin_trylock_irqsave(lock, flags) \
244 ({ \
245 local_irq_save(flags); \
246 raw_spin_trylock(lock) ? \
247 1 : ({ local_irq_restore(flags); 0; }); \
251 * raw_spin_can_lock - would raw_spin_trylock() succeed?
252 * @lock: the spinlock in question.
254 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
256 /* Include rwlock functions */
257 #include <linux/rwlock.h>
260 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
262 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
263 # include <linux/spinlock_api_smp.h>
264 #else
265 # include <linux/spinlock_api_up.h>
266 #endif
269 * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
272 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
274 return &lock->rlock;
277 #define spin_lock_init(_lock) \
278 do { \
279 spinlock_check(_lock); \
280 raw_spin_lock_init(&(_lock)->rlock); \
281 } while (0)
283 static inline void spin_lock(spinlock_t *lock)
285 raw_spin_lock(&lock->rlock);
288 static inline void spin_lock_bh(spinlock_t *lock)
290 raw_spin_lock_bh(&lock->rlock);
293 static inline int spin_trylock(spinlock_t *lock)
295 return raw_spin_trylock(&lock->rlock);
298 #define spin_lock_nested(lock, subclass) \
299 do { \
300 raw_spin_lock_nested(spinlock_check(lock), subclass); \
301 } while (0)
303 #define spin_lock_nest_lock(lock, nest_lock) \
304 do { \
305 raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \
306 } while (0)
308 static inline void spin_lock_irq(spinlock_t *lock)
310 raw_spin_lock_irq(&lock->rlock);
313 #define spin_lock_irqsave(lock, flags) \
314 do { \
315 raw_spin_lock_irqsave(spinlock_check(lock), flags); \
316 } while (0)
318 #define spin_lock_irqsave_nested(lock, flags, subclass) \
319 do { \
320 raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
321 } while (0)
323 static inline void spin_unlock(spinlock_t *lock)
325 raw_spin_unlock(&lock->rlock);
328 static inline void spin_unlock_bh(spinlock_t *lock)
330 raw_spin_unlock_bh(&lock->rlock);
333 static inline void spin_unlock_irq(spinlock_t *lock)
335 raw_spin_unlock_irq(&lock->rlock);
338 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
340 raw_spin_unlock_irqrestore(&lock->rlock, flags);
343 static inline int spin_trylock_bh(spinlock_t *lock)
345 return raw_spin_trylock_bh(&lock->rlock);
348 static inline int spin_trylock_irq(spinlock_t *lock)
350 return raw_spin_trylock_irq(&lock->rlock);
353 #define spin_trylock_irqsave(lock, flags) \
354 ({ \
355 raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
358 static inline void spin_unlock_wait(spinlock_t *lock)
360 raw_spin_unlock_wait(&lock->rlock);
363 static inline int spin_is_locked(spinlock_t *lock)
365 return raw_spin_is_locked(&lock->rlock);
368 static inline int spin_is_contended(spinlock_t *lock)
370 return raw_spin_is_contended(&lock->rlock);
373 static inline int spin_can_lock(spinlock_t *lock)
375 return raw_spin_can_lock(&lock->rlock);
378 static inline void assert_spin_locked(spinlock_t *lock)
380 assert_raw_spin_locked(&lock->rlock);
384 * Pull the atomic_t declaration:
385 * (asm-mips/atomic.h needs above definitions)
387 #include <linux/atomic.h>
389 * atomic_dec_and_lock - lock on reaching reference count zero
390 * @atomic: the atomic counter
391 * @lock: the spinlock in question
393 * Decrements @atomic by 1. If the result is 0, returns true and locks
394 * @lock. Returns false for all other cases.
396 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
397 #define atomic_dec_and_lock(atomic, lock) \
398 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
400 #endif /* __LINUX_SPINLOCK_H */