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1da177e4 LT |
1 | #ifndef __LINUX_SPINLOCK_H |
2 | #define __LINUX_SPINLOCK_H | |
3 | ||
4 | /* | |
fb1c8f93 IM |
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 | * | |
fb3a6bbc | 11 | * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the |
fb1c8f93 IM |
12 | * initializers |
13 | * | |
14 | * linux/spinlock_types.h: | |
15 | * defines the generic type and initializers | |
16 | * | |
0199c4e6 | 17 | * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel |
fb1c8f93 IM |
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: | |
0199c4e6 | 37 | * contains the arch_spin_*()/etc. version of UP |
fb1c8f93 IM |
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. | |
1da177e4 LT |
47 | */ |
48 | ||
3f307891 | 49 | #include <linux/typecheck.h> |
1da177e4 LT |
50 | #include <linux/preempt.h> |
51 | #include <linux/linkage.h> | |
52 | #include <linux/compiler.h> | |
df9ee292 | 53 | #include <linux/irqflags.h> |
1da177e4 LT |
54 | #include <linux/thread_info.h> |
55 | #include <linux/kernel.h> | |
56 | #include <linux/stringify.h> | |
676dcb8b | 57 | #include <linux/bottom_half.h> |
96f951ed | 58 | #include <asm/barrier.h> |
1da177e4 | 59 | |
1da177e4 LT |
60 | |
61 | /* | |
62 | * Must define these before including other files, inline functions need them | |
63 | */ | |
75ddb0e8 | 64 | #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME |
1da177e4 LT |
65 | |
66 | #define LOCK_SECTION_START(extra) \ | |
67 | ".subsection 1\n\t" \ | |
68 | extra \ | |
69 | ".ifndef " LOCK_SECTION_NAME "\n\t" \ | |
70 | LOCK_SECTION_NAME ":\n\t" \ | |
71 | ".endif\n" | |
72 | ||
73 | #define LOCK_SECTION_END \ | |
74 | ".previous\n\t" | |
75 | ||
ec701584 | 76 | #define __lockfunc __attribute__((section(".spinlock.text"))) |
1da177e4 LT |
77 | |
78 | /* | |
fb3a6bbc | 79 | * Pull the arch_spinlock_t and arch_rwlock_t definitions: |
1da177e4 | 80 | */ |
fb1c8f93 | 81 | #include <linux/spinlock_types.h> |
1da177e4 | 82 | |
1da177e4 | 83 | /* |
25985edc | 84 | * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them): |
1da177e4 | 85 | */ |
8a25d5de | 86 | #ifdef CONFIG_SMP |
fb1c8f93 | 87 | # include <asm/spinlock.h> |
1da177e4 | 88 | #else |
fb1c8f93 | 89 | # include <linux/spinlock_up.h> |
1da177e4 LT |
90 | #endif |
91 | ||
8a25d5de | 92 | #ifdef CONFIG_DEBUG_SPINLOCK |
c2f21ce2 TG |
93 | extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, |
94 | struct lock_class_key *key); | |
95 | # define raw_spin_lock_init(lock) \ | |
8a25d5de IM |
96 | do { \ |
97 | static struct lock_class_key __key; \ | |
98 | \ | |
c2f21ce2 | 99 | __raw_spin_lock_init((lock), #lock, &__key); \ |
8a25d5de IM |
100 | } while (0) |
101 | ||
102 | #else | |
c2f21ce2 TG |
103 | # define raw_spin_lock_init(lock) \ |
104 | do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0) | |
8a25d5de IM |
105 | #endif |
106 | ||
c2f21ce2 | 107 | #define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock) |
fb1c8f93 | 108 | |
95c354fe | 109 | #ifdef CONFIG_GENERIC_LOCKBREAK |
c2f21ce2 | 110 | #define raw_spin_is_contended(lock) ((lock)->break_lock) |
95c354fe | 111 | #else |
a5ef7ca0 | 112 | |
0199c4e6 | 113 | #ifdef arch_spin_is_contended |
c2f21ce2 | 114 | #define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock) |
a5ef7ca0 | 115 | #else |
c2f21ce2 | 116 | #define raw_spin_is_contended(lock) (((void)(lock), 0)) |
0199c4e6 | 117 | #endif /*arch_spin_is_contended*/ |
95c354fe NP |
118 | #endif |
119 | ||
e0acd0a6 ON |
120 | /* |
121 | * Despite its name it doesn't necessarily has to be a full barrier. | |
122 | * It should only guarantee that a STORE before the critical section | |
d956028e | 123 | * can not be reordered with LOADs and STOREs inside this section. |
e0acd0a6 ON |
124 | * spin_lock() is the one-way barrier, this LOAD can not escape out |
125 | * of the region. So the default implementation simply ensures that | |
126 | * a STORE can not move into the critical section, smp_wmb() should | |
127 | * serialize it with another STORE done by spin_lock(). | |
128 | */ | |
129 | #ifndef smp_mb__before_spinlock | |
130 | #define smp_mb__before_spinlock() smp_wmb() | |
ad462769 JO |
131 | #endif |
132 | ||
fb1c8f93 | 133 | /** |
c2f21ce2 | 134 | * raw_spin_unlock_wait - wait until the spinlock gets unlocked |
fb1c8f93 IM |
135 | * @lock: the spinlock in question. |
136 | */ | |
c2f21ce2 | 137 | #define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock) |
fb1c8f93 | 138 | |
fb1c8f93 | 139 | #ifdef CONFIG_DEBUG_SPINLOCK |
b97c4bc1 | 140 | extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); |
9828ea9d TG |
141 | #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) |
142 | extern int do_raw_spin_trylock(raw_spinlock_t *lock); | |
b97c4bc1 | 143 | extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); |
fb1c8f93 | 144 | #else |
b97c4bc1 | 145 | static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) |
c2f21ce2 | 146 | { |
b97c4bc1 | 147 | __acquire(lock); |
c2f21ce2 TG |
148 | arch_spin_lock(&lock->raw_lock); |
149 | } | |
150 | ||
151 | static inline void | |
b97c4bc1 | 152 | do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) |
c2f21ce2 | 153 | { |
b97c4bc1 | 154 | __acquire(lock); |
c2f21ce2 TG |
155 | arch_spin_lock_flags(&lock->raw_lock, *flags); |
156 | } | |
157 | ||
9828ea9d | 158 | static inline int do_raw_spin_trylock(raw_spinlock_t *lock) |
c2f21ce2 TG |
159 | { |
160 | return arch_spin_trylock(&(lock)->raw_lock); | |
161 | } | |
162 | ||
b97c4bc1 | 163 | static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) |
c2f21ce2 TG |
164 | { |
165 | arch_spin_unlock(&lock->raw_lock); | |
b97c4bc1 | 166 | __release(lock); |
c2f21ce2 | 167 | } |
fb1c8f93 | 168 | #endif |
1da177e4 | 169 | |
1da177e4 | 170 | /* |
ef12f109 TG |
171 | * Define the various spin_lock methods. Note we define these |
172 | * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The | |
173 | * various methods are defined as nops in the case they are not | |
174 | * required. | |
1da177e4 | 175 | */ |
9c1721aa | 176 | #define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock)) |
1da177e4 | 177 | |
9c1721aa | 178 | #define raw_spin_lock(lock) _raw_spin_lock(lock) |
8a25d5de IM |
179 | |
180 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
9c1721aa TG |
181 | # define raw_spin_lock_nested(lock, subclass) \ |
182 | _raw_spin_lock_nested(lock, subclass) | |
183 | ||
c2f21ce2 | 184 | # define raw_spin_lock_nest_lock(lock, nest_lock) \ |
b7d39aff PZ |
185 | do { \ |
186 | typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ | |
9c1721aa | 187 | _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ |
b7d39aff | 188 | } while (0) |
8a25d5de | 189 | #else |
4999201a BVA |
190 | /* |
191 | * Always evaluate the 'subclass' argument to avoid that the compiler | |
192 | * warns about set-but-not-used variables when building with | |
193 | * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. | |
194 | */ | |
195 | # define raw_spin_lock_nested(lock, subclass) \ | |
196 | _raw_spin_lock(((void)(subclass), (lock))) | |
9c1721aa | 197 | # define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) |
8a25d5de IM |
198 | #endif |
199 | ||
fb1c8f93 | 200 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
b8e6ec86 | 201 | |
c2f21ce2 | 202 | #define raw_spin_lock_irqsave(lock, flags) \ |
3f307891 SR |
203 | do { \ |
204 | typecheck(unsigned long, flags); \ | |
9c1721aa | 205 | flags = _raw_spin_lock_irqsave(lock); \ |
3f307891 | 206 | } while (0) |
cfd3ef23 AV |
207 | |
208 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
c2f21ce2 | 209 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
3f307891 SR |
210 | do { \ |
211 | typecheck(unsigned long, flags); \ | |
9c1721aa | 212 | flags = _raw_spin_lock_irqsave_nested(lock, subclass); \ |
3f307891 | 213 | } while (0) |
cfd3ef23 | 214 | #else |
c2f21ce2 | 215 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
3f307891 SR |
216 | do { \ |
217 | typecheck(unsigned long, flags); \ | |
9c1721aa | 218 | flags = _raw_spin_lock_irqsave(lock); \ |
3f307891 | 219 | } while (0) |
cfd3ef23 AV |
220 | #endif |
221 | ||
1da177e4 | 222 | #else |
b8e6ec86 | 223 | |
c2f21ce2 | 224 | #define raw_spin_lock_irqsave(lock, flags) \ |
3f307891 SR |
225 | do { \ |
226 | typecheck(unsigned long, flags); \ | |
9c1721aa | 227 | _raw_spin_lock_irqsave(lock, flags); \ |
3f307891 | 228 | } while (0) |
ef12f109 | 229 | |
c2f21ce2 TG |
230 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
231 | raw_spin_lock_irqsave(lock, flags) | |
cfd3ef23 | 232 | |
1da177e4 LT |
233 | #endif |
234 | ||
9c1721aa TG |
235 | #define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock) |
236 | #define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock) | |
237 | #define raw_spin_unlock(lock) _raw_spin_unlock(lock) | |
238 | #define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock) | |
1da177e4 | 239 | |
c2f21ce2 TG |
240 | #define raw_spin_unlock_irqrestore(lock, flags) \ |
241 | do { \ | |
242 | typecheck(unsigned long, flags); \ | |
9c1721aa | 243 | _raw_spin_unlock_irqrestore(lock, flags); \ |
3f307891 | 244 | } while (0) |
9c1721aa | 245 | #define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock) |
1da177e4 | 246 | |
9c1721aa TG |
247 | #define raw_spin_trylock_bh(lock) \ |
248 | __cond_lock(lock, _raw_spin_trylock_bh(lock)) | |
1da177e4 | 249 | |
c2f21ce2 | 250 | #define raw_spin_trylock_irq(lock) \ |
1da177e4 LT |
251 | ({ \ |
252 | local_irq_disable(); \ | |
c2f21ce2 | 253 | raw_spin_trylock(lock) ? \ |
fb1c8f93 | 254 | 1 : ({ local_irq_enable(); 0; }); \ |
1da177e4 LT |
255 | }) |
256 | ||
c2f21ce2 | 257 | #define raw_spin_trylock_irqsave(lock, flags) \ |
1da177e4 LT |
258 | ({ \ |
259 | local_irq_save(flags); \ | |
c2f21ce2 | 260 | raw_spin_trylock(lock) ? \ |
fb1c8f93 | 261 | 1 : ({ local_irq_restore(flags); 0; }); \ |
1da177e4 LT |
262 | }) |
263 | ||
c2f21ce2 TG |
264 | /** |
265 | * raw_spin_can_lock - would raw_spin_trylock() succeed? | |
266 | * @lock: the spinlock in question. | |
267 | */ | |
268 | #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock)) | |
269 | ||
270 | /* Include rwlock functions */ | |
271 | #include <linux/rwlock.h> | |
272 | ||
273 | /* | |
274 | * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: | |
275 | */ | |
276 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) | |
277 | # include <linux/spinlock_api_smp.h> | |
278 | #else | |
279 | # include <linux/spinlock_api_up.h> | |
280 | #endif | |
281 | ||
282 | /* | |
283 | * Map the spin_lock functions to the raw variants for PREEMPT_RT=n | |
284 | */ | |
285 | ||
3490565b | 286 | static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock) |
c2f21ce2 TG |
287 | { |
288 | return &lock->rlock; | |
289 | } | |
290 | ||
291 | #define spin_lock_init(_lock) \ | |
292 | do { \ | |
293 | spinlock_check(_lock); \ | |
294 | raw_spin_lock_init(&(_lock)->rlock); \ | |
295 | } while (0) | |
296 | ||
3490565b | 297 | static __always_inline void spin_lock(spinlock_t *lock) |
c2f21ce2 TG |
298 | { |
299 | raw_spin_lock(&lock->rlock); | |
300 | } | |
301 | ||
3490565b | 302 | static __always_inline void spin_lock_bh(spinlock_t *lock) |
c2f21ce2 TG |
303 | { |
304 | raw_spin_lock_bh(&lock->rlock); | |
305 | } | |
306 | ||
3490565b | 307 | static __always_inline int spin_trylock(spinlock_t *lock) |
c2f21ce2 TG |
308 | { |
309 | return raw_spin_trylock(&lock->rlock); | |
310 | } | |
311 | ||
312 | #define spin_lock_nested(lock, subclass) \ | |
313 | do { \ | |
314 | raw_spin_lock_nested(spinlock_check(lock), subclass); \ | |
315 | } while (0) | |
316 | ||
317 | #define spin_lock_nest_lock(lock, nest_lock) \ | |
318 | do { \ | |
319 | raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \ | |
320 | } while (0) | |
321 | ||
3490565b | 322 | static __always_inline void spin_lock_irq(spinlock_t *lock) |
c2f21ce2 TG |
323 | { |
324 | raw_spin_lock_irq(&lock->rlock); | |
325 | } | |
326 | ||
327 | #define spin_lock_irqsave(lock, flags) \ | |
328 | do { \ | |
329 | raw_spin_lock_irqsave(spinlock_check(lock), flags); \ | |
330 | } while (0) | |
331 | ||
332 | #define spin_lock_irqsave_nested(lock, flags, subclass) \ | |
333 | do { \ | |
334 | raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \ | |
335 | } while (0) | |
336 | ||
3490565b | 337 | static __always_inline void spin_unlock(spinlock_t *lock) |
c2f21ce2 TG |
338 | { |
339 | raw_spin_unlock(&lock->rlock); | |
340 | } | |
341 | ||
3490565b | 342 | static __always_inline void spin_unlock_bh(spinlock_t *lock) |
c2f21ce2 TG |
343 | { |
344 | raw_spin_unlock_bh(&lock->rlock); | |
345 | } | |
346 | ||
3490565b | 347 | static __always_inline void spin_unlock_irq(spinlock_t *lock) |
c2f21ce2 TG |
348 | { |
349 | raw_spin_unlock_irq(&lock->rlock); | |
350 | } | |
351 | ||
3490565b | 352 | static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) |
c2f21ce2 TG |
353 | { |
354 | raw_spin_unlock_irqrestore(&lock->rlock, flags); | |
355 | } | |
356 | ||
3490565b | 357 | static __always_inline int spin_trylock_bh(spinlock_t *lock) |
c2f21ce2 TG |
358 | { |
359 | return raw_spin_trylock_bh(&lock->rlock); | |
360 | } | |
361 | ||
3490565b | 362 | static __always_inline int spin_trylock_irq(spinlock_t *lock) |
c2f21ce2 TG |
363 | { |
364 | return raw_spin_trylock_irq(&lock->rlock); | |
365 | } | |
366 | ||
367 | #define spin_trylock_irqsave(lock, flags) \ | |
368 | ({ \ | |
369 | raw_spin_trylock_irqsave(spinlock_check(lock), flags); \ | |
370 | }) | |
371 | ||
6016ffc3 PM |
372 | /** |
373 | * spin_unlock_wait - Interpose between successive critical sections | |
374 | * @lock: the spinlock whose critical sections are to be interposed. | |
375 | * | |
376 | * Semantically this is equivalent to a spin_lock() immediately | |
377 | * followed by a spin_unlock(). However, most architectures have | |
378 | * more efficient implementations in which the spin_unlock_wait() | |
379 | * cannot block concurrent lock acquisition, and in some cases | |
380 | * where spin_unlock_wait() does not write to the lock variable. | |
381 | * Nevertheless, spin_unlock_wait() can have high overhead, so if | |
382 | * you feel the need to use it, please check to see if there is | |
383 | * a better way to get your job done. | |
384 | * | |
385 | * The ordering guarantees provided by spin_unlock_wait() are: | |
386 | * | |
387 | * 1. All accesses preceding the spin_unlock_wait() happen before | |
388 | * any accesses in later critical sections for this same lock. | |
389 | * 2. All accesses following the spin_unlock_wait() happen after | |
390 | * any accesses in earlier critical sections for this same lock. | |
391 | */ | |
3490565b | 392 | static __always_inline void spin_unlock_wait(spinlock_t *lock) |
c2f21ce2 TG |
393 | { |
394 | raw_spin_unlock_wait(&lock->rlock); | |
395 | } | |
396 | ||
3490565b | 397 | static __always_inline int spin_is_locked(spinlock_t *lock) |
c2f21ce2 TG |
398 | { |
399 | return raw_spin_is_locked(&lock->rlock); | |
400 | } | |
401 | ||
3490565b | 402 | static __always_inline int spin_is_contended(spinlock_t *lock) |
c2f21ce2 TG |
403 | { |
404 | return raw_spin_is_contended(&lock->rlock); | |
405 | } | |
406 | ||
3490565b | 407 | static __always_inline int spin_can_lock(spinlock_t *lock) |
c2f21ce2 TG |
408 | { |
409 | return raw_spin_can_lock(&lock->rlock); | |
410 | } | |
411 | ||
4ebc1b4b | 412 | #define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) |
c2f21ce2 | 413 | |
1da177e4 | 414 | /* |
fb1c8f93 IM |
415 | * Pull the atomic_t declaration: |
416 | * (asm-mips/atomic.h needs above definitions) | |
1da177e4 | 417 | */ |
60063497 | 418 | #include <linux/atomic.h> |
fb1c8f93 IM |
419 | /** |
420 | * atomic_dec_and_lock - lock on reaching reference count zero | |
421 | * @atomic: the atomic counter | |
422 | * @lock: the spinlock in question | |
dc07e721 BF |
423 | * |
424 | * Decrements @atomic by 1. If the result is 0, returns true and locks | |
425 | * @lock. Returns false for all other cases. | |
1da177e4 | 426 | */ |
fb1c8f93 IM |
427 | extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); |
428 | #define atomic_dec_and_lock(atomic, lock) \ | |
dcc8e559 | 429 | __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) |
1da177e4 | 430 | |
1da177e4 | 431 | #endif /* __LINUX_SPINLOCK_H */ |