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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
82extern 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) \
97do { \
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) \
112do { \
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/* The lock does not imply full memory barrier. */
136#ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
137static inline void smp_mb__after_lock(void) { smp_mb(); }
138#endif
139
140/**
141 * spin_unlock_wait - wait until the spinlock gets unlocked
142 * @lock: the spinlock in question.
143 */
144#define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock)
145
146#ifdef CONFIG_DEBUG_SPINLOCK
147 extern void _raw_spin_lock(spinlock_t *lock);
148#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
149 extern int _raw_spin_trylock(spinlock_t *lock);
150 extern void _raw_spin_unlock(spinlock_t *lock);
151 extern void _raw_read_lock(rwlock_t *lock);
152#define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
153 extern int _raw_read_trylock(rwlock_t *lock);
154 extern void _raw_read_unlock(rwlock_t *lock);
155 extern void _raw_write_lock(rwlock_t *lock);
156#define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
157 extern int _raw_write_trylock(rwlock_t *lock);
158 extern void _raw_write_unlock(rwlock_t *lock);
159#else
160# define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock)
161# define _raw_spin_lock_flags(lock, flags) \
162 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
163# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock)
164# define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock)
165# define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock)
166# define _raw_read_lock_flags(lock, flags) \
167 __raw_read_lock_flags(&(lock)->raw_lock, *(flags))
168# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock)
169# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock)
170# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock)
171# define _raw_write_lock_flags(lock, flags) \
172 __raw_write_lock_flags(&(lock)->raw_lock, *(flags))
173# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock)
174# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock)
175#endif
176
177#define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock)
178#define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock)
179
180/*
181 * Define the various spin_lock and rw_lock methods. Note we define these
182 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
183 * methods are defined as nops in the case they are not required.
184 */
185#define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock))
186#define read_trylock(lock) __cond_lock(lock, _read_trylock(lock))
187#define write_trylock(lock) __cond_lock(lock, _write_trylock(lock))
188
189#define spin_lock(lock) _spin_lock(lock)
190
191#ifdef CONFIG_DEBUG_LOCK_ALLOC
192# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
193# define spin_lock_nest_lock(lock, nest_lock) \
194 do { \
195 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
196 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
197 } while (0)
198#else
199# define spin_lock_nested(lock, subclass) _spin_lock(lock)
200# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
201#endif
202
203#define write_lock(lock) _write_lock(lock)
204#define read_lock(lock) _read_lock(lock)
205
206#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
207
208#define spin_lock_irqsave(lock, flags) \
209 do { \
210 typecheck(unsigned long, flags); \
211 flags = _spin_lock_irqsave(lock); \
212 } while (0)
213#define read_lock_irqsave(lock, flags) \
214 do { \
215 typecheck(unsigned long, flags); \
216 flags = _read_lock_irqsave(lock); \
217 } while (0)
218#define write_lock_irqsave(lock, flags) \
219 do { \
220 typecheck(unsigned long, flags); \
221 flags = _write_lock_irqsave(lock); \
222 } while (0)
223
224#ifdef CONFIG_DEBUG_LOCK_ALLOC
225#define spin_lock_irqsave_nested(lock, flags, subclass) \
226 do { \
227 typecheck(unsigned long, flags); \
228 flags = _spin_lock_irqsave_nested(lock, subclass); \
229 } while (0)
230#else
231#define spin_lock_irqsave_nested(lock, flags, subclass) \
232 do { \
233 typecheck(unsigned long, flags); \
234 flags = _spin_lock_irqsave(lock); \
235 } while (0)
236#endif
237
238#else
239
240#define spin_lock_irqsave(lock, flags) \
241 do { \
242 typecheck(unsigned long, flags); \
243 _spin_lock_irqsave(lock, flags); \
244 } while (0)
245#define read_lock_irqsave(lock, flags) \
246 do { \
247 typecheck(unsigned long, flags); \
248 _read_lock_irqsave(lock, flags); \
249 } while (0)
250#define write_lock_irqsave(lock, flags) \
251 do { \
252 typecheck(unsigned long, flags); \
253 _write_lock_irqsave(lock, flags); \
254 } while (0)
255#define spin_lock_irqsave_nested(lock, flags, subclass) \
256 spin_lock_irqsave(lock, flags)
257
258#endif
259
260#define spin_lock_irq(lock) _spin_lock_irq(lock)
261#define spin_lock_bh(lock) _spin_lock_bh(lock)
262#define read_lock_irq(lock) _read_lock_irq(lock)
263#define read_lock_bh(lock) _read_lock_bh(lock)
264#define write_lock_irq(lock) _write_lock_irq(lock)
265#define write_lock_bh(lock) _write_lock_bh(lock)
266#define spin_unlock(lock) _spin_unlock(lock)
267#define read_unlock(lock) _read_unlock(lock)
268#define write_unlock(lock) _write_unlock(lock)
269#define spin_unlock_irq(lock) _spin_unlock_irq(lock)
270#define read_unlock_irq(lock) _read_unlock_irq(lock)
271#define write_unlock_irq(lock) _write_unlock_irq(lock)
272
273#define spin_unlock_irqrestore(lock, flags) \
274 do { \
275 typecheck(unsigned long, flags); \
276 _spin_unlock_irqrestore(lock, flags); \
277 } while (0)
278#define spin_unlock_bh(lock) _spin_unlock_bh(lock)
279
280#define read_unlock_irqrestore(lock, flags) \
281 do { \
282 typecheck(unsigned long, flags); \
283 _read_unlock_irqrestore(lock, flags); \
284 } while (0)
285#define read_unlock_bh(lock) _read_unlock_bh(lock)
286
287#define write_unlock_irqrestore(lock, flags) \
288 do { \
289 typecheck(unsigned long, flags); \
290 _write_unlock_irqrestore(lock, flags); \
291 } while (0)
292#define write_unlock_bh(lock) _write_unlock_bh(lock)
293
294#define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))
295
296#define spin_trylock_irq(lock) \
297({ \
298 local_irq_disable(); \
299 spin_trylock(lock) ? \
300 1 : ({ local_irq_enable(); 0; }); \
301})
302
303#define spin_trylock_irqsave(lock, flags) \
304({ \
305 local_irq_save(flags); \
306 spin_trylock(lock) ? \
307 1 : ({ local_irq_restore(flags); 0; }); \
308})
309
310#define write_trylock_irqsave(lock, flags) \
311({ \
312 local_irq_save(flags); \
313 write_trylock(lock) ? \
314 1 : ({ local_irq_restore(flags); 0; }); \
315})
316
317/*
318 * Pull the atomic_t declaration:
319 * (asm-mips/atomic.h needs above definitions)
320 */
321#include <asm/atomic.h>
322/**
323 * atomic_dec_and_lock - lock on reaching reference count zero
324 * @atomic: the atomic counter
325 * @lock: the spinlock in question
326 *
327 * Decrements @atomic by 1. If the result is 0, returns true and locks
328 * @lock. Returns false for all other cases.
329 */
330extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
331#define atomic_dec_and_lock(atomic, lock) \
332 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
333
334/**
335 * spin_can_lock - would spin_trylock() succeed?
336 * @lock: the spinlock in question.
337 */
338#define spin_can_lock(lock) (!spin_is_locked(lock))
339
340/*
341 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
342 */
343#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
344# include <linux/spinlock_api_smp.h>
345#else
346# include <linux/spinlock_api_up.h>
347#endif
348
349#endif /* __LINUX_SPINLOCK_H */