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