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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef __LINUX_SPINLOCK_H
2#define __LINUX_SPINLOCK_H
3
4/*
Ingo Molnarfb1c8f92005-09-10 00:25:56 -07005 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 */
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049#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>
Andrew Morton676dcb82006-12-06 20:31:30 -080055#include <linux/bottom_half.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#include <asm/system.h>
58
59/*
60 * Must define these before including other files, inline functions need them
61 */
Ustyugov Romanf83b5e32005-09-23 08:42:11 +040062#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
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/*
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070077 * Pull the raw_spinlock_t and raw_rwlock_t definitions:
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 */
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070079#include <linux/spinlock_types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070081extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070083/*
84 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
85 */
Ingo Molnar8a25d5d2006-07-03 00:24:54 -070086#ifdef CONFIG_SMP
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070087# include <asm/spinlock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070088#else
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070089# include <linux/spinlock_up.h>
90#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Ingo Molnar8a25d5d2006-07-03 00:24:54 -070092#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) \
96do { \
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) \
111do { \
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700121#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136#endif
137
138#ifdef CONFIG_DEBUG_SPINLOCK
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700139 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);
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700143 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149#else
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700150# 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))
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700153# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock)
154# define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock)
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700155# define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock)
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700156# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock)
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700157# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock)
158# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock)
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700159# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock)
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700160# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161#endif
162
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700163#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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
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 */
Josh Triplettdcc8e552006-09-29 02:01:03 -0700171#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))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700175#define spin_lock(lock) _spin_lock(lock)
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700176
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
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700183#define write_lock(lock) _write_lock(lock)
184#define read_lock(lock) _read_lock(lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700186#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800187
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)
Arjan van de Vencfd3ef22006-11-25 11:09:37 -0800191
192#ifdef CONFIG_DEBUG_LOCK_ALLOC
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800193#define spin_lock_irqsave_nested(lock, flags, subclass) \
194 flags = _spin_lock_irqsave_nested(lock, subclass)
Arjan van de Vencfd3ef22006-11-25 11:09:37 -0800195#else
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800196#define spin_lock_irqsave_nested(lock, flags, subclass) \
197 flags = _spin_lock_irqsave(lock)
Arjan van de Vencfd3ef22006-11-25 11:09:37 -0800198#endif
199
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200#else
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800201
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)
Arjan van de Vencfd3ef22006-11-25 11:09:37 -0800205#define spin_lock_irqsave_nested(lock, flags, subclass) \
206 spin_lock_irqsave(lock, flags)
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208#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
Ingo Molnarbda98682005-10-30 14:59:44 -0800219/*
220 * We inline the unlock functions in the nondebug case:
221 */
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700222#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
223 !defined(CONFIG_SMP)
Ingo Molnarbda98682005-10-30 14:59:44 -0800224# define spin_unlock(lock) _spin_unlock(lock)
225# define read_unlock(lock) _read_unlock(lock)
226# define write_unlock(lock) _write_unlock(lock)
Ingo Molnarbda98682005-10-30 14:59:44 -0800227# 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
Pavel Roskinc75fb882007-02-10 01:46:37 -0800231# 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) \
238do { \
239 __raw_spin_unlock(&(lock)->raw_lock); \
240 __release(lock); \
241 local_irq_enable(); \
242} while (0)
243# define read_unlock_irq(lock) \
244do { \
245 __raw_read_unlock(&(lock)->raw_lock); \
246 __release(lock); \
247 local_irq_enable(); \
248} while (0)
249# define write_unlock_irq(lock) \
250do { \
251 __raw_write_unlock(&(lock)->raw_lock); \
252 __release(lock); \
253 local_irq_enable(); \
254} while (0)
Ingo Molnarbda98682005-10-30 14:59:44 -0800255#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700257#define spin_unlock_irqrestore(lock, flags) \
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800258 _spin_unlock_irqrestore(lock, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259#define spin_unlock_bh(lock) _spin_unlock_bh(lock)
260
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700261#define read_unlock_irqrestore(lock, flags) \
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800262 _read_unlock_irqrestore(lock, flags)
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700263#define read_unlock_bh(lock) _read_unlock_bh(lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700265#define write_unlock_irqrestore(lock, flags) \
Linus Torvaldsb8e6ec82006-11-26 16:27:17 -0800266 _write_unlock_irqrestore(lock, flags)
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700267#define write_unlock_bh(lock) _write_unlock_bh(lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Josh Triplettdcc8e552006-09-29 02:01:03 -0700269#define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
271#define spin_trylock_irq(lock) \
272({ \
273 local_irq_disable(); \
Josh Triplett303912e2006-09-29 02:01:00 -0700274 spin_trylock(lock) ? \
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700275 1 : ({ local_irq_enable(); 0; }); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276})
277
278#define spin_trylock_irqsave(lock, flags) \
279({ \
280 local_irq_save(flags); \
Josh Triplett303912e2006-09-29 02:01:00 -0700281 spin_trylock(lock) ? \
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700282 1 : ({ local_irq_restore(flags); 0; }); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283})
284
Satyam Sharmae1f4a882007-07-15 23:39:24 -0700285#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
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700292/*
Heiko Carstense81ce1f2007-03-05 00:30:51 -0800293 * Locks two spinlocks l1 and l2.
294 * l1_first indicates if spinlock l1 should be taken first.
295 */
296static 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 */
315static 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/*
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700330 * Pull the atomic_t declaration:
331 * (asm-mips/atomic.h needs above definitions)
332 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333#include <asm/atomic.h>
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700334/**
335 * atomic_dec_and_lock - lock on reaching reference count zero
336 * @atomic: the atomic counter
337 * @lock: the spinlock in question
338 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700340#define atomic_dec_and_lock(atomic, lock) \
Josh Triplettdcc8e552006-09-29 02:01:03 -0700341 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
343/**
344 * spin_can_lock - would spin_trylock() succeed?
345 * @lock: the spinlock in question.
346 */
Ingo Molnarfb1c8f92005-09-10 00:25:56 -0700347#define spin_can_lock(lock) (!spin_is_locked(lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
349#endif /* __LINUX_SPINLOCK_H */