86088213334a48d3a0617d59af49af1610ecb2db
[linux-2.6.git] / 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/arch_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 arch_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 arch_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 arch_rwlock_t definitions:
79  */
80 #include <linux/spinlock_types.h>
81
82 /*
83  * Pull the arch_spin*() 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 __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
93                                    struct lock_class_key *key);
94 # define raw_spin_lock_init(lock)                               \
95 do {                                                            \
96         static struct lock_class_key __key;                     \
97                                                                 \
98         __raw_spin_lock_init((lock), #lock, &__key);            \
99 } while (0)
100
101 #else
102 # define raw_spin_lock_init(lock)                               \
103         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
104 #endif
105
106 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
107
108 #ifdef CONFIG_GENERIC_LOCKBREAK
109 #define raw_spin_is_contended(lock) ((lock)->break_lock)
110 #else
111
112 #ifdef arch_spin_is_contended
113 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
114 #else
115 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
116 #endif /*arch_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  * raw_spin_unlock_wait - wait until the spinlock gets unlocked
126  * @lock: the spinlock in question.
127  */
128 #define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
129
130 #ifdef CONFIG_DEBUG_SPINLOCK
131  extern void do_raw_spin_lock(raw_spinlock_t *lock);
132 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
133  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
134  extern void do_raw_spin_unlock(raw_spinlock_t *lock);
135 #else
136 static inline void do_raw_spin_lock(raw_spinlock_t *lock)
137 {
138         arch_spin_lock(&lock->raw_lock);
139 }
140
141 static inline void
142 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags)
143 {
144         arch_spin_lock_flags(&lock->raw_lock, *flags);
145 }
146
147 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
148 {
149         return arch_spin_trylock(&(lock)->raw_lock);
150 }
151
152 static inline void do_raw_spin_unlock(raw_spinlock_t *lock)
153 {
154         arch_spin_unlock(&lock->raw_lock);
155 }
156 #endif
157
158 /*
159  * Define the various spin_lock methods.  Note we define these
160  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
161  * various methods are defined as nops in the case they are not
162  * required.
163  */
164 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
165
166 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
167
168 #ifdef CONFIG_DEBUG_LOCK_ALLOC
169 # define raw_spin_lock_nested(lock, subclass) \
170         _raw_spin_lock_nested(lock, subclass)
171
172 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
173          do {                                                           \
174                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
175                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
176          } while (0)
177 #else
178 # define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
179 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
180 #endif
181
182 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
183
184 #define raw_spin_lock_irqsave(lock, flags)                      \
185         do {                                            \
186                 typecheck(unsigned long, flags);        \
187                 flags = _raw_spin_lock_irqsave(lock);   \
188         } while (0)
189
190 #ifdef CONFIG_DEBUG_LOCK_ALLOC
191 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
192         do {                                                            \
193                 typecheck(unsigned long, flags);                        \
194                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
195         } while (0)
196 #else
197 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
198         do {                                                            \
199                 typecheck(unsigned long, flags);                        \
200                 flags = _raw_spin_lock_irqsave(lock);                   \
201         } while (0)
202 #endif
203
204 #else
205
206 #define raw_spin_lock_irqsave(lock, flags)              \
207         do {                                            \
208                 typecheck(unsigned long, flags);        \
209                 _raw_spin_lock_irqsave(lock, flags);    \
210         } while (0)
211
212 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
213         raw_spin_lock_irqsave(lock, flags)
214
215 #endif
216
217 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
218 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
219 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
220 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
221
222 #define raw_spin_unlock_irqrestore(lock, flags)         \
223         do {                                                    \
224                 typecheck(unsigned long, flags);                \
225                 _raw_spin_unlock_irqrestore(lock, flags);       \
226         } while (0)
227 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
228
229 #define raw_spin_trylock_bh(lock) \
230         __cond_lock(lock, _raw_spin_trylock_bh(lock))
231
232 #define raw_spin_trylock_irq(lock) \
233 ({ \
234         local_irq_disable(); \
235         raw_spin_trylock(lock) ? \
236         1 : ({ local_irq_enable(); 0;  }); \
237 })
238
239 #define raw_spin_trylock_irqsave(lock, flags) \
240 ({ \
241         local_irq_save(flags); \
242         raw_spin_trylock(lock) ? \
243         1 : ({ local_irq_restore(flags); 0; }); \
244 })
245
246 /**
247  * raw_spin_can_lock - would raw_spin_trylock() succeed?
248  * @lock: the spinlock in question.
249  */
250 #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
251
252 /* Include rwlock functions */
253 #include <linux/rwlock.h>
254
255 /*
256  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
257  */
258 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
259 # include <linux/spinlock_api_smp.h>
260 #else
261 # include <linux/spinlock_api_up.h>
262 #endif
263
264 /*
265  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
266  */
267
268 static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
269 {
270         return &lock->rlock;
271 }
272
273 #define spin_lock_init(_lock)                           \
274 do {                                                    \
275         spinlock_check(_lock);                          \
276         raw_spin_lock_init(&(_lock)->rlock);            \
277 } while (0)
278
279 static inline void spin_lock(spinlock_t *lock)
280 {
281         raw_spin_lock(&lock->rlock);
282 }
283
284 static inline void spin_lock_bh(spinlock_t *lock)
285 {
286         raw_spin_lock_bh(&lock->rlock);
287 }
288
289 static inline int spin_trylock(spinlock_t *lock)
290 {
291         return raw_spin_trylock(&lock->rlock);
292 }
293
294 #define spin_lock_nested(lock, subclass)                        \
295 do {                                                            \
296         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
297 } while (0)
298
299 #define spin_lock_nest_lock(lock, nest_lock)                            \
300 do {                                                                    \
301         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
302 } while (0)
303
304 static inline void spin_lock_irq(spinlock_t *lock)
305 {
306         raw_spin_lock_irq(&lock->rlock);
307 }
308
309 #define spin_lock_irqsave(lock, flags)                          \
310 do {                                                            \
311         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
312 } while (0)
313
314 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
315 do {                                                                    \
316         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
317 } while (0)
318
319 static inline void spin_unlock(spinlock_t *lock)
320 {
321         raw_spin_unlock(&lock->rlock);
322 }
323
324 static inline void spin_unlock_bh(spinlock_t *lock)
325 {
326         raw_spin_unlock_bh(&lock->rlock);
327 }
328
329 static inline void spin_unlock_irq(spinlock_t *lock)
330 {
331         raw_spin_unlock_irq(&lock->rlock);
332 }
333
334 static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
335 {
336         raw_spin_unlock_irqrestore(&lock->rlock, flags);
337 }
338
339 static inline int spin_trylock_bh(spinlock_t *lock)
340 {
341         return raw_spin_trylock_bh(&lock->rlock);
342 }
343
344 static inline int spin_trylock_irq(spinlock_t *lock)
345 {
346         return raw_spin_trylock_irq(&lock->rlock);
347 }
348
349 #define spin_trylock_irqsave(lock, flags)                       \
350 ({                                                              \
351         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
352 })
353
354 static inline void spin_unlock_wait(spinlock_t *lock)
355 {
356         raw_spin_unlock_wait(&lock->rlock);
357 }
358
359 static inline int spin_is_locked(spinlock_t *lock)
360 {
361         return raw_spin_is_locked(&lock->rlock);
362 }
363
364 static inline int spin_is_contended(spinlock_t *lock)
365 {
366         return raw_spin_is_contended(&lock->rlock);
367 }
368
369 static inline int spin_can_lock(spinlock_t *lock)
370 {
371         return raw_spin_can_lock(&lock->rlock);
372 }
373
374 static inline void assert_spin_locked(spinlock_t *lock)
375 {
376         assert_raw_spin_locked(&lock->rlock);
377 }
378
379 /*
380  * Pull the atomic_t declaration:
381  * (asm-mips/atomic.h needs above definitions)
382  */
383 #include <asm/atomic.h>
384 /**
385  * atomic_dec_and_lock - lock on reaching reference count zero
386  * @atomic: the atomic counter
387  * @lock: the spinlock in question
388  *
389  * Decrements @atomic by 1.  If the result is 0, returns true and locks
390  * @lock.  Returns false for all other cases.
391  */
392 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
393 #define atomic_dec_and_lock(atomic, lock) \
394                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
395
396 #endif /* __LINUX_SPINLOCK_H */