57f670d78f7c6af9db9716fdf12709dbeef4bf86
[sfrench/cifs-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/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/irqflags.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 #define spin_lock_irqsave(lock, flags)                  \
188         do {                                            \
189                 BUILD_CHECK_IRQ_FLAGS(flags);           \
190                 flags = _spin_lock_irqsave(lock);       \
191         } while (0)
192 #define read_lock_irqsave(lock, flags)                  \
193         do {                                            \
194                 BUILD_CHECK_IRQ_FLAGS(flags);           \
195                 flags = _read_lock_irqsave(lock);       \
196         } while (0)
197 #define write_lock_irqsave(lock, flags)                 \
198         do {                                            \
199                 BUILD_CHECK_IRQ_FLAGS(flags);           \
200                 flags = _write_lock_irqsave(lock);      \
201         } while (0)
202
203 #ifdef CONFIG_DEBUG_LOCK_ALLOC
204 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
205         do {                                                            \
206                 BUILD_CHECK_IRQ_FLAGS(flags);                           \
207                 flags = _spin_lock_irqsave_nested(lock, subclass);      \
208         } while (0)
209 #else
210 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
211         do {                                                            \
212                 BUILD_CHECK_IRQ_FLAGS(flags);                           \
213                 flags = _spin_lock_irqsave(lock);                       \
214         } while (0)
215 #endif
216
217 #else
218 #define spin_lock_irqsave(lock, flags)                  \
219         do {                                            \
220                 BUILD_CHECK_IRQ_FLAGS(flags);           \
221                 _spin_lock_irqsave(lock, flags);        \
222         } while (0)
223 #define read_lock_irqsave(lock, flags)                  \
224         do {                                            \
225                 BUILD_CHECK_IRQ_FLAGS(flags);           \
226                 _read_lock_irqsave(lock, flags);        \
227         } while (0)
228 #define write_lock_irqsave(lock, flags)                 \
229         do {                                            \
230                 BUILD_CHECK_IRQ_FLAGS(flags);           \
231                 _write_lock_irqsave(lock, flags);       \
232         } while (0)
233 #define spin_lock_irqsave_nested(lock, flags, subclass) \
234         spin_lock_irqsave(lock, flags)
235
236 #endif
237
238 #define spin_lock_irq(lock)             _spin_lock_irq(lock)
239 #define spin_lock_bh(lock)              _spin_lock_bh(lock)
240
241 #define read_lock_irq(lock)             _read_lock_irq(lock)
242 #define read_lock_bh(lock)              _read_lock_bh(lock)
243
244 #define write_lock_irq(lock)            _write_lock_irq(lock)
245 #define write_lock_bh(lock)             _write_lock_bh(lock)
246
247 /*
248  * We inline the unlock functions in the nondebug case:
249  */
250 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
251         !defined(CONFIG_SMP)
252 # define spin_unlock(lock)              _spin_unlock(lock)
253 # define read_unlock(lock)              _read_unlock(lock)
254 # define write_unlock(lock)             _write_unlock(lock)
255 # define spin_unlock_irq(lock)          _spin_unlock_irq(lock)
256 # define read_unlock_irq(lock)          _read_unlock_irq(lock)
257 # define write_unlock_irq(lock)         _write_unlock_irq(lock)
258 #else
259 # define spin_unlock(lock)              __raw_spin_unlock(&(lock)->raw_lock)
260 # define read_unlock(lock)              __raw_read_unlock(&(lock)->raw_lock)
261 # define write_unlock(lock)             __raw_write_unlock(&(lock)->raw_lock)
262 # define spin_unlock_irq(lock) \
263     do { __raw_spin_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
264 # define read_unlock_irq(lock) \
265     do { __raw_read_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
266 # define write_unlock_irq(lock) \
267     do { __raw_write_unlock(&(lock)->raw_lock); local_irq_enable(); } while (0)
268 #endif
269
270 #define spin_unlock_irqrestore(lock, flags) \
271         do {                                            \
272                 BUILD_CHECK_IRQ_FLAGS(flags);           \
273                 _spin_unlock_irqrestore(lock, flags);   \
274         } while (0)
275 #define spin_unlock_bh(lock)            _spin_unlock_bh(lock)
276
277 #define read_unlock_irqrestore(lock, flags) \
278         do {                                            \
279                 BUILD_CHECK_IRQ_FLAGS(flags);           \
280                 _read_unlock_irqrestore(lock, flags);   \
281         } while (0)
282 #define read_unlock_bh(lock)            _read_unlock_bh(lock)
283
284 #define write_unlock_irqrestore(lock, flags) \
285         do {                                            \
286                 BUILD_CHECK_IRQ_FLAGS(flags);           \
287                 _write_unlock_irqrestore(lock, flags);  \
288         } while (0)
289 #define write_unlock_bh(lock)           _write_unlock_bh(lock)
290
291 #define spin_trylock_bh(lock)   __cond_lock(lock, _spin_trylock_bh(lock))
292
293 #define spin_trylock_irq(lock) \
294 ({ \
295         local_irq_disable(); \
296         spin_trylock(lock) ? \
297         1 : ({ local_irq_enable(); 0;  }); \
298 })
299
300 #define spin_trylock_irqsave(lock, flags) \
301 ({ \
302         BUILD_CHECK_IRQ_FLAGS(flags); \
303         local_irq_save(flags); \
304         spin_trylock(lock) ? \
305         1 : ({ local_irq_restore(flags); 0; }); \
306 })
307
308 /*
309  * Pull the atomic_t declaration:
310  * (asm-mips/atomic.h needs above definitions)
311  */
312 #include <asm/atomic.h>
313 /**
314  * atomic_dec_and_lock - lock on reaching reference count zero
315  * @atomic: the atomic counter
316  * @lock: the spinlock in question
317  */
318 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
319 #define atomic_dec_and_lock(atomic, lock) \
320                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
321
322 /**
323  * spin_can_lock - would spin_trylock() succeed?
324  * @lock: the spinlock in question.
325  */
326 #define spin_can_lock(lock)     (!spin_is_locked(lock))
327
328 #endif /* __LINUX_SPINLOCK_H */