locking: Cleanup the name space completely
[linux-2.6.git] / kernel / spinlock.c
1 /*
2  * Copyright (2004) Linus Torvalds
3  *
4  * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
5  *
6  * Copyright (2004, 2005) Ingo Molnar
7  *
8  * This file contains the spinlock/rwlock implementations for the
9  * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
10  *
11  * Note that some architectures have special knowledge about the
12  * stack frames of these functions in their profile_pc. If you
13  * change anything significant here that could change the stack
14  * frame contact the architecture maintainers.
15  */
16
17 #include <linux/linkage.h>
18 #include <linux/preempt.h>
19 #include <linux/spinlock.h>
20 #include <linux/interrupt.h>
21 #include <linux/debug_locks.h>
22 #include <linux/module.h>
23
24 /*
25  * If lockdep is enabled then we use the non-preemption spin-ops
26  * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
27  * not re-enabled during lock-acquire (which the preempt-spin-ops do):
28  */
29 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
30 /*
31  * The __lock_function inlines are taken from
32  * include/linux/spinlock_api_smp.h
33  */
34 #else
35 #define raw_read_can_lock(l)    read_can_lock(l)
36 #define raw_write_can_lock(l)   write_can_lock(l)
37 /*
38  * We build the __lock_function inlines here. They are too large for
39  * inlining all over the place, but here is only one user per function
40  * which embedds them into the calling _lock_function below.
41  *
42  * This could be a long-held lock. We both prepare to spin for a long
43  * time (making _this_ CPU preemptable if possible), and we also signal
44  * towards that other CPU that it should break the lock ASAP.
45  */
46 #define BUILD_LOCK_OPS(op, locktype)                                    \
47 void __lockfunc __raw_##op##_lock(locktype##_t *lock)                   \
48 {                                                                       \
49         for (;;) {                                                      \
50                 preempt_disable();                                      \
51                 if (likely(do_raw_##op##_trylock(lock)))                \
52                         break;                                          \
53                 preempt_enable();                                       \
54                                                                         \
55                 if (!(lock)->break_lock)                                \
56                         (lock)->break_lock = 1;                         \
57                 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
58                         arch_##op##_relax(&lock->raw_lock);             \
59         }                                                               \
60         (lock)->break_lock = 0;                                         \
61 }                                                                       \
62                                                                         \
63 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)  \
64 {                                                                       \
65         unsigned long flags;                                            \
66                                                                         \
67         for (;;) {                                                      \
68                 preempt_disable();                                      \
69                 local_irq_save(flags);                                  \
70                 if (likely(do_raw_##op##_trylock(lock)))                \
71                         break;                                          \
72                 local_irq_restore(flags);                               \
73                 preempt_enable();                                       \
74                                                                         \
75                 if (!(lock)->break_lock)                                \
76                         (lock)->break_lock = 1;                         \
77                 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
78                         arch_##op##_relax(&lock->raw_lock);             \
79         }                                                               \
80         (lock)->break_lock = 0;                                         \
81         return flags;                                                   \
82 }                                                                       \
83                                                                         \
84 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)               \
85 {                                                                       \
86         _raw_##op##_lock_irqsave(lock);                                 \
87 }                                                                       \
88                                                                         \
89 void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)                \
90 {                                                                       \
91         unsigned long flags;                                            \
92                                                                         \
93         /*                                                      */      \
94         /* Careful: we must exclude softirqs too, hence the     */      \
95         /* irq-disabling. We use the generic preemption-aware   */      \
96         /* function:                                            */      \
97         /**/                                                            \
98         flags = _raw_##op##_lock_irqsave(lock);                         \
99         local_bh_disable();                                             \
100         local_irq_restore(flags);                                       \
101 }                                                                       \
102
103 /*
104  * Build preemption-friendly versions of the following
105  * lock-spinning functions:
106  *
107  *         __[spin|read|write]_lock()
108  *         __[spin|read|write]_lock_irq()
109  *         __[spin|read|write]_lock_irqsave()
110  *         __[spin|read|write]_lock_bh()
111  */
112 BUILD_LOCK_OPS(spin, raw_spinlock);
113 BUILD_LOCK_OPS(read, rwlock);
114 BUILD_LOCK_OPS(write, rwlock);
115
116 #endif
117
118 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
119 int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
120 {
121         return __raw_spin_trylock(lock);
122 }
123 EXPORT_SYMBOL(_raw_spin_trylock);
124 #endif
125
126 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
127 int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
128 {
129         return __raw_spin_trylock_bh(lock);
130 }
131 EXPORT_SYMBOL(_raw_spin_trylock_bh);
132 #endif
133
134 #ifndef CONFIG_INLINE_SPIN_LOCK
135 void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
136 {
137         __raw_spin_lock(lock);
138 }
139 EXPORT_SYMBOL(_raw_spin_lock);
140 #endif
141
142 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
143 unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
144 {
145         return __raw_spin_lock_irqsave(lock);
146 }
147 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
148 #endif
149
150 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
151 void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
152 {
153         __raw_spin_lock_irq(lock);
154 }
155 EXPORT_SYMBOL(_raw_spin_lock_irq);
156 #endif
157
158 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
159 void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
160 {
161         __raw_spin_lock_bh(lock);
162 }
163 EXPORT_SYMBOL(_raw_spin_lock_bh);
164 #endif
165
166 #ifndef CONFIG_INLINE_SPIN_UNLOCK
167 void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
168 {
169         __raw_spin_unlock(lock);
170 }
171 EXPORT_SYMBOL(_raw_spin_unlock);
172 #endif
173
174 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
175 void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
176 {
177         __raw_spin_unlock_irqrestore(lock, flags);
178 }
179 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
180 #endif
181
182 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
183 void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
184 {
185         __raw_spin_unlock_irq(lock);
186 }
187 EXPORT_SYMBOL(_raw_spin_unlock_irq);
188 #endif
189
190 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
191 void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
192 {
193         __raw_spin_unlock_bh(lock);
194 }
195 EXPORT_SYMBOL(_raw_spin_unlock_bh);
196 #endif
197
198 #ifndef CONFIG_INLINE_READ_TRYLOCK
199 int __lockfunc _raw_read_trylock(rwlock_t *lock)
200 {
201         return __raw_read_trylock(lock);
202 }
203 EXPORT_SYMBOL(_raw_read_trylock);
204 #endif
205
206 #ifndef CONFIG_INLINE_READ_LOCK
207 void __lockfunc _raw_read_lock(rwlock_t *lock)
208 {
209         __raw_read_lock(lock);
210 }
211 EXPORT_SYMBOL(_raw_read_lock);
212 #endif
213
214 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
215 unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
216 {
217         return __raw_read_lock_irqsave(lock);
218 }
219 EXPORT_SYMBOL(_raw_read_lock_irqsave);
220 #endif
221
222 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
223 void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
224 {
225         __raw_read_lock_irq(lock);
226 }
227 EXPORT_SYMBOL(_raw_read_lock_irq);
228 #endif
229
230 #ifndef CONFIG_INLINE_READ_LOCK_BH
231 void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
232 {
233         __raw_read_lock_bh(lock);
234 }
235 EXPORT_SYMBOL(_raw_read_lock_bh);
236 #endif
237
238 #ifndef CONFIG_INLINE_READ_UNLOCK
239 void __lockfunc _raw_read_unlock(rwlock_t *lock)
240 {
241         __raw_read_unlock(lock);
242 }
243 EXPORT_SYMBOL(_raw_read_unlock);
244 #endif
245
246 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
247 void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
248 {
249         __raw_read_unlock_irqrestore(lock, flags);
250 }
251 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
252 #endif
253
254 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
255 void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
256 {
257         __raw_read_unlock_irq(lock);
258 }
259 EXPORT_SYMBOL(_raw_read_unlock_irq);
260 #endif
261
262 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
263 void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
264 {
265         __raw_read_unlock_bh(lock);
266 }
267 EXPORT_SYMBOL(_raw_read_unlock_bh);
268 #endif
269
270 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
271 int __lockfunc _raw_write_trylock(rwlock_t *lock)
272 {
273         return __raw_write_trylock(lock);
274 }
275 EXPORT_SYMBOL(_raw_write_trylock);
276 #endif
277
278 #ifndef CONFIG_INLINE_WRITE_LOCK
279 void __lockfunc _raw_write_lock(rwlock_t *lock)
280 {
281         __raw_write_lock(lock);
282 }
283 EXPORT_SYMBOL(_raw_write_lock);
284 #endif
285
286 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
287 unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
288 {
289         return __raw_write_lock_irqsave(lock);
290 }
291 EXPORT_SYMBOL(_raw_write_lock_irqsave);
292 #endif
293
294 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
295 void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
296 {
297         __raw_write_lock_irq(lock);
298 }
299 EXPORT_SYMBOL(_raw_write_lock_irq);
300 #endif
301
302 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
303 void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
304 {
305         __raw_write_lock_bh(lock);
306 }
307 EXPORT_SYMBOL(_raw_write_lock_bh);
308 #endif
309
310 #ifndef CONFIG_INLINE_WRITE_UNLOCK
311 void __lockfunc _raw_write_unlock(rwlock_t *lock)
312 {
313         __raw_write_unlock(lock);
314 }
315 EXPORT_SYMBOL(_raw_write_unlock);
316 #endif
317
318 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
319 void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
320 {
321         __raw_write_unlock_irqrestore(lock, flags);
322 }
323 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
324 #endif
325
326 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
327 void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
328 {
329         __raw_write_unlock_irq(lock);
330 }
331 EXPORT_SYMBOL(_raw_write_unlock_irq);
332 #endif
333
334 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
335 void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
336 {
337         __raw_write_unlock_bh(lock);
338 }
339 EXPORT_SYMBOL(_raw_write_unlock_bh);
340 #endif
341
342 #ifdef CONFIG_DEBUG_LOCK_ALLOC
343
344 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
345 {
346         preempt_disable();
347         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
348         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
349 }
350 EXPORT_SYMBOL(_raw_spin_lock_nested);
351
352 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
353                                                    int subclass)
354 {
355         unsigned long flags;
356
357         local_irq_save(flags);
358         preempt_disable();
359         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
360         LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
361                                 do_raw_spin_lock_flags, &flags);
362         return flags;
363 }
364 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
365
366 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
367                                      struct lockdep_map *nest_lock)
368 {
369         preempt_disable();
370         spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
371         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
372 }
373 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
374
375 #endif
376
377 notrace int in_lock_functions(unsigned long addr)
378 {
379         /* Linker adds these: start and end of __lockfunc functions */
380         extern char __lock_text_start[], __lock_text_end[];
381
382         return addr >= (unsigned long)__lock_text_start
383         && addr < (unsigned long)__lock_text_end;
384 }
385 EXPORT_SYMBOL(in_lock_functions);