Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / 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/preempt.h>
50 #include <linux/linkage.h>
51 #include <linux/compiler.h>
52 #include <linux/thread_info.h>
53 #include <linux/kernel.h>
54 #include <linux/stringify.h>
55 #include <linux/bottom_half.h>
56
57 #include <asm/system.h>
58
59 /*
60  * Must define these before including other files, inline functions need them
61  */
62 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
63
64 #define LOCK_SECTION_START(extra)               \
65         ".subsection 1\n\t"                     \
66         extra                                   \
67         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
68         LOCK_SECTION_NAME ":\n\t"               \
69         ".endif\n"
70
71 #define LOCK_SECTION_END                        \
72         ".previous\n\t"
73
74 #define __lockfunc fastcall __attribute__((section(".spinlock.text")))
75
76 /*
77  * Pull the raw_spinlock_t and raw_rwlock_t definitions:
78  */
79 #include <linux/spinlock_types.h>
80
81 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
82
83 /*
84  * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
85  */
86 #ifdef CONFIG_SMP
87 # include <asm/spinlock.h>
88 #else
89 # include <linux/spinlock_up.h>
90 #endif
91
92 #ifdef CONFIG_DEBUG_SPINLOCK
93   extern void __spin_lock_init(spinlock_t *lock, const char *name,
94                                struct lock_class_key *key);
95 # define spin_lock_init(lock)                                   \
96 do {                                                            \
97         static struct lock_class_key __key;                     \
98                                                                 \
99         __spin_lock_init((lock), #lock, &__key);                \
100 } while (0)
101
102 #else
103 # define spin_lock_init(lock)                                   \
104         do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
105 #endif
106
107 #ifdef CONFIG_DEBUG_SPINLOCK
108   extern void __rwlock_init(rwlock_t *lock, const char *name,
109                             struct lock_class_key *key);
110 # define rwlock_init(lock)                                      \
111 do {                                                            \
112         static struct lock_class_key __key;                     \
113                                                                 \
114         __rwlock_init((lock), #lock, &__key);                   \
115 } while (0)
116 #else
117 # define rwlock_init(lock)                                      \
118         do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
119 #endif
120
121 #define spin_is_locked(lock)    __raw_spin_is_locked(&(lock)->raw_lock)
122
123 /**
124  * spin_unlock_wait - wait until the spinlock gets unlocked
125  * @lock: the spinlock in question.
126  */
127 #define spin_unlock_wait(lock)  __raw_spin_unlock_wait(&(lock)->raw_lock)
128
129 /*
130  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
131  */
132 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
133 # include <linux/spinlock_api_smp.h>
134 #else
135 # include <linux/spinlock_api_up.h>
136 #endif
137
138 #ifdef CONFIG_DEBUG_SPINLOCK
139  extern void _raw_spin_lock(spinlock_t *lock);
140 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
141  extern int _raw_spin_trylock(spinlock_t *lock);
142  extern void _raw_spin_unlock(spinlock_t *lock);
143  extern void _raw_read_lock(rwlock_t *lock);
144  extern int _raw_read_trylock(rwlock_t *lock);
145  extern void _raw_read_unlock(rwlock_t *lock);
146  extern void _raw_write_lock(rwlock_t *lock);
147  extern int _raw_write_trylock(rwlock_t *lock);
148  extern void _raw_write_unlock(rwlock_t *lock);
149 #else
150 # define _raw_spin_lock(lock)           __raw_spin_lock(&(lock)->raw_lock)
151 # define _raw_spin_lock_flags(lock, flags) \
152                 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
153 # define _raw_spin_trylock(lock)        __raw_spin_trylock(&(lock)->raw_lock)
154 # define _raw_spin_unlock(lock)         __raw_spin_unlock(&(lock)->raw_lock)
155 # define _raw_read_lock(rwlock)         __raw_read_lock(&(rwlock)->raw_lock)
156 # define _raw_read_trylock(rwlock)      __raw_read_trylock(&(rwlock)->raw_lock)
157 # define _raw_read_unlock(rwlock)       __raw_read_unlock(&(rwlock)->raw_lock)
158 # define _raw_write_lock(rwlock)        __raw_write_lock(&(rwlock)->raw_lock)
159 # define _raw_write_trylock(rwlock)     __raw_write_trylock(&(rwlock)->raw_lock)
160 # define _raw_write_unlock(rwlock)      __raw_write_unlock(&(rwlock)->raw_lock)
161 #endif
162
163 #define read_can_lock(rwlock)           __raw_read_can_lock(&(rwlock)->raw_lock)
164 #define write_can_lock(rwlock)          __raw_write_can_lock(&(rwlock)->raw_lock)
165
166 /*
167  * Define the various spin_lock and rw_lock methods.  Note we define these
168  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
169  * methods are defined as nops in the case they are not required.
170  */
171 #define spin_trylock(lock)              __cond_lock(lock, _spin_trylock(lock))
172 #define read_trylock(lock)              __cond_lock(lock, _read_trylock(lock))
173 #define write_trylock(lock)             __cond_lock(lock, _write_trylock(lock))
174
175 #define spin_lock(lock)                 _spin_lock(lock)
176
177 #ifdef CONFIG_DEBUG_LOCK_ALLOC
178 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
179 #else
180 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
181 #endif
182
183 #define write_lock(lock)                _write_lock(lock)
184 #define read_lock(lock)                 _read_lock(lock)
185
186 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
187
188 #define spin_lock_irqsave(lock, flags)  flags = _spin_lock_irqsave(lock)
189 #define read_lock_irqsave(lock, flags)  flags = _read_lock_irqsave(lock)
190 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
191
192 #ifdef CONFIG_DEBUG_LOCK_ALLOC
193 #define spin_lock_irqsave_nested(lock, flags, subclass) \
194         flags = _spin_lock_irqsave_nested(lock, subclass)
195 #else
196 #define spin_lock_irqsave_nested(lock, flags, subclass) \
197         flags = _spin_lock_irqsave(lock)
198 #endif
199
200 #else
201
202 #define spin_lock_irqsave(lock, flags)  _spin_lock_irqsave(lock, flags)
203 #define read_lock_irqsave(lock, flags)  _read_lock_irqsave(lock, flags)
204 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
205 #define spin_lock_irqsave_nested(lock, flags, subclass) \
206         spin_lock_irqsave(lock, flags)
207
208 #endif
209
210 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
211 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
212
213 #define read_lock_irq(lock)             _read_lock_irq(lock)
214 #define read_lock_bh(lock)              _read_lock_bh(lock)
215
216 #define write_lock_irq(lock)            _write_lock_irq(lock)
217 #define write_lock_bh(lock)             _write_lock_bh(lock)
218
219 /*
220  * We inline the unlock functions in the nondebug case:
221  */
222 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
223         !defined(CONFIG_SMP)
224 # define spin_unlock(lock)              _spin_unlock(lock)
225 # define read_unlock(lock)              _read_unlock(lock)
226 # define write_unlock(lock)             _write_unlock(lock)
227 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
228 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
229 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
230 #else
231 # define spin_unlock(lock) \
232     do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
233 # define read_unlock(lock) \
234     do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
235 # define write_unlock(lock) \
236     do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
237 # define spin_unlock_irq(lock)                  \
238 do {                                            \
239         __raw_spin_unlock(&(lock)->raw_lock);   \
240         __release(lock);                        \
241         local_irq_enable();                     \
242 } while (0)
243 # define read_unlock_irq(lock)                  \
244 do {                                            \
245         __raw_read_unlock(&(lock)->raw_lock);   \
246         __release(lock);                        \
247         local_irq_enable();                     \
248 } while (0)
249 # define write_unlock_irq(lock)                 \
250 do {                                            \
251         __raw_write_unlock(&(lock)->raw_lock);  \
252         __release(lock);                        \
253         local_irq_enable();                     \
254 } while (0)
255 #endif
256
257 #define spin_unlock_irqrestore(lock, flags) \
258                                         _spin_unlock_irqrestore(lock, flags)
259 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
260
261 #define read_unlock_irqrestore(lock, flags) \
262                                         _read_unlock_irqrestore(lock, flags)
263 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
264
265 #define write_unlock_irqrestore(lock, flags) \
266                                         _write_unlock_irqrestore(lock, flags)
267 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
268
269 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
270
271 #define spin_trylock_irq(lock) \
272 ({ \
273         local_irq_disable(); \
274         spin_trylock(lock) ? \
275         1 : ({ local_irq_enable(); 0;  }); \
276 })
277
278 #define spin_trylock_irqsave(lock, flags) \
279 ({ \
280         local_irq_save(flags); \
281         spin_trylock(lock) ? \
282         1 : ({ local_irq_restore(flags); 0; }); \
283 })
284
285 #define write_trylock_irqsave(lock, flags) \
286 ({ \
287         local_irq_save(flags); \
288         write_trylock(lock) ? \
289         1 : ({ local_irq_restore(flags); 0; }); \
290 })
291
292 /*
293  * Locks two spinlocks l1 and l2.
294  * l1_first indicates if spinlock l1 should be taken first.
295  */
296 static inline void double_spin_lock(spinlock_t *l1, spinlock_t *l2,
297                                     bool l1_first)
298         __acquires(l1)
299         __acquires(l2)
300 {
301         if (l1_first) {
302                 spin_lock(l1);
303                 spin_lock(l2);
304         } else {
305                 spin_lock(l2);
306                 spin_lock(l1);
307         }
308 }
309
310 /*
311  * Unlocks two spinlocks l1 and l2.
312  * l1_taken_first indicates if spinlock l1 was taken first and therefore
313  * should be released after spinlock l2.
314  */
315 static inline void double_spin_unlock(spinlock_t *l1, spinlock_t *l2,
316                                       bool l1_taken_first)
317         __releases(l1)
318         __releases(l2)
319 {
320         if (l1_taken_first) {
321                 spin_unlock(l2);
322                 spin_unlock(l1);
323         } else {
324                 spin_unlock(l1);
325                 spin_unlock(l2);
326         }
327 }
328
329 /*
330  * Pull the atomic_t declaration:
331  * (asm-mips/atomic.h needs above definitions)
332  */
333 #include <asm/atomic.h>
334 /**
335  * atomic_dec_and_lock - lock on reaching reference count zero
336  * @atomic: the atomic counter
337  * @lock: the spinlock in question
338  */
339 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
340 #define atomic_dec_and_lock(atomic, lock) \
341                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
342
343 /**
344  * spin_can_lock - would spin_trylock() succeed?
345  * @lock: the spinlock in question.
346  */
347 #define spin_can_lock(lock)     (!spin_is_locked(lock))
348
349 #endif /* __LINUX_SPINLOCK_H */