Allow rwlocks to re-enable interrupts
[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 raw_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 raw_spinlock_t and raw_rwlock_t definitions:
79  */
80 #include <linux/spinlock_types.h>
81
82 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
83
84 /*
85  * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
86  */
87 #ifdef CONFIG_SMP
88 # include <asm/spinlock.h>
89 #else
90 # include <linux/spinlock_up.h>
91 #endif
92
93 #ifdef CONFIG_DEBUG_SPINLOCK
94   extern void __spin_lock_init(spinlock_t *lock, const char *name,
95                                struct lock_class_key *key);
96 # define spin_lock_init(lock)                                   \
97 do {                                                            \
98         static struct lock_class_key __key;                     \
99                                                                 \
100         __spin_lock_init((lock), #lock, &__key);                \
101 } while (0)
102
103 #else
104 # define spin_lock_init(lock)                                   \
105         do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
106 #endif
107
108 #ifdef CONFIG_DEBUG_SPINLOCK
109   extern void __rwlock_init(rwlock_t *lock, const char *name,
110                             struct lock_class_key *key);
111 # define rwlock_init(lock)                                      \
112 do {                                                            \
113         static struct lock_class_key __key;                     \
114                                                                 \
115         __rwlock_init((lock), #lock, &__key);                   \
116 } while (0)
117 #else
118 # define rwlock_init(lock)                                      \
119         do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
120 #endif
121
122 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
123
124 #ifdef CONFIG_GENERIC_LOCKBREAK
125 #define spin_is_contended(lock) ((lock)->break_lock)
126 #else
127
128 #ifdef __raw_spin_is_contended
129 #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
130 #else
131 #define spin_is_contended(lock) (((void)(lock), 0))
132 #endif /*__raw_spin_is_contended*/
133 #endif
134
135 /**
136  * spin_unlock_wait - wait until the spinlock gets unlocked
137  * @lock: the spinlock in question.
138  */
139 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
140
141 /*
142  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
143  */
144 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
145 # include <linux/spinlock_api_smp.h>
146 #else
147 # include <linux/spinlock_api_up.h>
148 #endif
149
150 #ifdef CONFIG_DEBUG_SPINLOCK
151  extern void _raw_spin_lock(spinlock_t *lock);
152 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
153  extern int _raw_spin_trylock(spinlock_t *lock);
154  extern void _raw_spin_unlock(spinlock_t *lock);
155  extern void _raw_read_lock(rwlock_t *lock);
156 #define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
157  extern int _raw_read_trylock(rwlock_t *lock);
158  extern void _raw_read_unlock(rwlock_t *lock);
159  extern void _raw_write_lock(rwlock_t *lock);
160 #define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
161  extern int _raw_write_trylock(rwlock_t *lock);
162  extern void _raw_write_unlock(rwlock_t *lock);
163 #else
164 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
165 # define _raw_spin_lock_flags(lock, flags) \
166                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
167 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
168 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
169 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
170 # define _raw_read_lock_flags(lock, flags) \
171                 __raw_read_lock_flags(&(lock)->raw_lock, *(flags))
172 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
173 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
174 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
175 # define _raw_write_lock_flags(lock, flags) \
176                 __raw_write_lock_flags(&(lock)->raw_lock, *(flags))
177 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
178 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
179 #endif
180
181 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
182 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
183
184 /*
185  * Define the various spin_lock and rw_lock methods.  Note we define these
186  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
187  * methods are defined as nops in the case they are not required.
188  */
189 #define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
190 #define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
191 #define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
192
193 #define spin_lock(lock)                 _spin_lock(lock)
194
195 #ifdef CONFIG_DEBUG_LOCK_ALLOC
196 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
197 # define spin_lock_nest_lock(lock, nest_lock)                           \
198          do {                                                           \
199                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
200                  _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);     \
201          } while (0)
202 #else
203 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
204 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
205 #endif
206
207 #define write_lock(lock)                _write_lock(lock)
208 #define read_lock(lock)                 _read_lock(lock)
209
210 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
211
212 #define spin_lock_irqsave(lock, flags)                  \
213         do {                                            \
214                 typecheck(unsigned long, flags);        \
215                 flags = _spin_lock_irqsave(lock);       \
216         } while (0)
217 #define read_lock_irqsave(lock, flags)                  \
218         do {                                            \
219                 typecheck(unsigned long, flags);        \
220                 flags = _read_lock_irqsave(lock);       \
221         } while (0)
222 #define write_lock_irqsave(lock, flags)                 \
223         do {                                            \
224                 typecheck(unsigned long, flags);        \
225                 flags = _write_lock_irqsave(lock);      \
226         } while (0)
227
228 #ifdef CONFIG_DEBUG_LOCK_ALLOC
229 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
230         do {                                                            \
231                 typecheck(unsigned long, flags);                        \
232                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
233         } while (0)
234 #else
235 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
236         do {                                                            \
237                 typecheck(unsigned long, flags);                        \
238                 flags = _spin_lock_irqsave(lock);                       \
239         } while (0)
240 #endif
241
242 #else
243
244 #define spin_lock_irqsave(lock, flags)                  \
245         do {                                            \
246                 typecheck(unsigned long, flags);        \
247                 _spin_lock_irqsave(lock, flags);        \
248         } while (0)
249 #define read_lock_irqsave(lock, flags)                  \
250         do {                                            \
251                 typecheck(unsigned long, flags);        \
252                 _read_lock_irqsave(lock, flags);        \
253         } while (0)
254 #define write_lock_irqsave(lock, flags)                 \
255         do {                                            \
256                 typecheck(unsigned long, flags);        \
257                 _write_lock_irqsave(lock, flags);       \
258         } while (0)
259 #define spin_lock_irqsave_nested(lock, flags, subclass) \
260         spin_lock_irqsave(lock, flags)
261
262 #endif
263
264 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
265 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
266
267 #define read_lock_irq(lock)             _read_lock_irq(lock)
268 #define read_lock_bh(lock)              _read_lock_bh(lock)
269
270 #define write_lock_irq(lock)            _write_lock_irq(lock)
271 #define write_lock_bh(lock)             _write_lock_bh(lock)
272
273 /*
274  * We inline the unlock functions in the nondebug case:
275  */
276 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
277         !defined(CONFIG_SMP)
278 # define spin_unlock(lock)              _spin_unlock(lock)
279 # define read_unlock(lock)              _read_unlock(lock)
280 # define write_unlock(lock)             _write_unlock(lock)
281 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
282 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
283 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
284 #else
285 # define spin_unlock(lock) \
286     do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
287 # define read_unlock(lock) \
288     do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
289 # define write_unlock(lock) \
290     do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
291 # define spin_unlock_irq(lock)                  \
292 do {                                            \
293         __raw_spin_unlock(&(lock)->raw_lock);   \
294         __release(lock);                        \
295         local_irq_enable();                     \
296 } while (0)
297 # define read_unlock_irq(lock)                  \
298 do {                                            \
299         __raw_read_unlock(&(lock)->raw_lock);   \
300         __release(lock);                        \
301         local_irq_enable();                     \
302 } while (0)
303 # define write_unlock_irq(lock)                 \
304 do {                                            \
305         __raw_write_unlock(&(lock)->raw_lock);  \
306         __release(lock);                        \
307         local_irq_enable();                     \
308 } while (0)
309 #endif
310
311 #define spin_unlock_irqrestore(lock, flags)             \
312         do {                                            \
313                 typecheck(unsigned long, flags);        \
314                 _spin_unlock_irqrestore(lock, flags);   \
315         } while (0)
316 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
317
318 #define read_unlock_irqrestore(lock, flags)             \
319         do {                                            \
320                 typecheck(unsigned long, flags);        \
321                 _read_unlock_irqrestore(lock, flags);   \
322         } while (0)
323 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
324
325 #define write_unlock_irqrestore(lock, flags)            \
326         do {                                            \
327                 typecheck(unsigned long, flags);        \
328                 _write_unlock_irqrestore(lock, flags);  \
329         } while (0)
330 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
331
332 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
333
334 #define spin_trylock_irq(lock) \
335 ({ \
336         local_irq_disable(); \
337         spin_trylock(lock) ? \
338         1 : ({ local_irq_enable(); 0;  }); \
339 })
340
341 #define spin_trylock_irqsave(lock, flags) \
342 ({ \
343         local_irq_save(flags); \
344         spin_trylock(lock) ? \
345         1 : ({ local_irq_restore(flags); 0; }); \
346 })
347
348 #define write_trylock_irqsave(lock, flags) \
349 ({ \
350         local_irq_save(flags); \
351         write_trylock(lock) ? \
352         1 : ({ local_irq_restore(flags); 0; }); \
353 })
354
355 /*
356  * Pull the atomic_t declaration:
357  * (asm-mips/atomic.h needs above definitions)
358  */
359 #include <asm/atomic.h>
360 /**
361  * atomic_dec_and_lock - lock on reaching reference count zero
362  * @atomic: the atomic counter
363  * @lock: the spinlock in question
364  *
365  * Decrements @atomic by 1.  If the result is 0, returns true and locks
366  * @lock.  Returns false for all other cases.
367  */
368 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
369 #define atomic_dec_and_lock(atomic, lock) \
370                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
371
372 /**
373  * spin_can_lock - would spin_trylock() succeed?
374  * @lock: the spinlock in question.
375  */
376 #define spin_can_lock(lock)     (!spin_is_locked(lock))
377
378 #endif /* __LINUX_SPINLOCK_H */