~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/linux/spinlock.h

Version: ~ [ linux-5.16 ] ~ [ linux-5.15.13 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.90 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.170 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.224 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.261 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.296 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.298 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef __LINUX_SPINLOCK_H
  3 #define __LINUX_SPINLOCK_H
  4 
  5 /*
  6  * include/linux/spinlock.h - generic spinlock/rwlock declarations
  7  *
  8  * here's the role of the various spinlock/rwlock related include files:
  9  *
 10  * on SMP builds:
 11  *
 12  *  asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
 13  *                        initializers
 14  *
 15  *  linux/spinlock_types.h:
 16  *                        defines the generic type and initializers
 17  *
 18  *  asm/spinlock.h:       contains the arch_spin_*()/etc. lowlevel
 19  *                        implementations, mostly inline assembly code
 20  *
 21  *   (also included on UP-debug builds:)
 22  *
 23  *  linux/spinlock_api_smp.h:
 24  *                        contains the prototypes for the _spin_*() APIs.
 25  *
 26  *  linux/spinlock.h:     builds the final spin_*() APIs.
 27  *
 28  * on UP builds:
 29  *
 30  *  linux/spinlock_type_up.h:
 31  *                        contains the generic, simplified UP spinlock type.
 32  *                        (which is an empty structure on non-debug builds)
 33  *
 34  *  linux/spinlock_types.h:
 35  *                        defines the generic type and initializers
 36  *
 37  *  linux/spinlock_up.h:
 38  *                        contains the arch_spin_*()/etc. version of UP
 39  *                        builds. (which are NOPs on non-debug, non-preempt
 40  *                        builds)
 41  *
 42  *   (included on UP-non-debug builds:)
 43  *
 44  *  linux/spinlock_api_up.h:
 45  *                        builds the _spin_*() APIs.
 46  *
 47  *  linux/spinlock.h:     builds the final spin_*() APIs.
 48  */
 49 
 50 #include <linux/typecheck.h>
 51 #include <linux/preempt.h>
 52 #include <linux/linkage.h>
 53 #include <linux/compiler.h>
 54 #include <linux/irqflags.h>
 55 #include <linux/thread_info.h>
 56 #include <linux/kernel.h>
 57 #include <linux/stringify.h>
 58 #include <linux/bottom_half.h>
 59 #include <linux/lockdep.h>
 60 #include <asm/barrier.h>
 61 #include <asm/mmiowb.h>
 62 
 63 
 64 /*
 65  * Must define these before including other files, inline functions need them
 66  */
 67 #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
 68 
 69 #define LOCK_SECTION_START(extra)               \
 70         ".subsection 1\n\t"                     \
 71         extra                                   \
 72         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
 73         LOCK_SECTION_NAME ":\n\t"               \
 74         ".endif\n"
 75 
 76 #define LOCK_SECTION_END                        \
 77         ".previous\n\t"
 78 
 79 #define __lockfunc __section(".spinlock.text")
 80 
 81 /*
 82  * Pull the arch_spinlock_t and arch_rwlock_t definitions:
 83  */
 84 #include <linux/spinlock_types.h>
 85 
 86 /*
 87  * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
 88  */
 89 #ifdef CONFIG_SMP
 90 # include <asm/spinlock.h>
 91 #else
 92 # include <linux/spinlock_up.h>
 93 #endif
 94 
 95 #ifdef CONFIG_DEBUG_SPINLOCK
 96   extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
 97                                    struct lock_class_key *key, short inner);
 98 
 99 # define raw_spin_lock_init(lock)                                       \
100 do {                                                                    \
101         static struct lock_class_key __key;                             \
102                                                                         \
103         __raw_spin_lock_init((lock), #lock, &__key, LD_WAIT_SPIN);      \
104 } while (0)
105 
106 #else
107 # define raw_spin_lock_init(lock)                               \
108         do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
109 #endif
110 
111 #define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
112 
113 #ifdef arch_spin_is_contended
114 #define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
115 #else
116 #define raw_spin_is_contended(lock)     (((void)(lock), 0))
117 #endif /*arch_spin_is_contended*/
118 
119 /*
120  * smp_mb__after_spinlock() provides the equivalent of a full memory barrier
121  * between program-order earlier lock acquisitions and program-order later
122  * memory accesses.
123  *
124  * This guarantees that the following two properties hold:
125  *
126  *   1) Given the snippet:
127  *
128  *        { X = 0;  Y = 0; }
129  *
130  *        CPU0                          CPU1
131  *
132  *        WRITE_ONCE(X, 1);             WRITE_ONCE(Y, 1);
133  *        spin_lock(S);                 smp_mb();
134  *        smp_mb__after_spinlock();     r1 = READ_ONCE(X);
135  *        r0 = READ_ONCE(Y);
136  *        spin_unlock(S);
137  *
138  *      it is forbidden that CPU0 does not observe CPU1's store to Y (r0 = 0)
139  *      and CPU1 does not observe CPU0's store to X (r1 = 0); see the comments
140  *      preceding the call to smp_mb__after_spinlock() in __schedule() and in
141  *      try_to_wake_up().
142  *
143  *   2) Given the snippet:
144  *
145  *  { X = 0;  Y = 0; }
146  *
147  *  CPU0                CPU1                            CPU2
148  *
149  *  spin_lock(S);       spin_lock(S);                   r1 = READ_ONCE(Y);
150  *  WRITE_ONCE(X, 1);   smp_mb__after_spinlock();       smp_rmb();
151  *  spin_unlock(S);     r0 = READ_ONCE(X);              r2 = READ_ONCE(X);
152  *                      WRITE_ONCE(Y, 1);
153  *                      spin_unlock(S);
154  *
155  *      it is forbidden that CPU0's critical section executes before CPU1's
156  *      critical section (r0 = 1), CPU2 observes CPU1's store to Y (r1 = 1)
157  *      and CPU2 does not observe CPU0's store to X (r2 = 0); see the comments
158  *      preceding the calls to smp_rmb() in try_to_wake_up() for similar
159  *      snippets but "projected" onto two CPUs.
160  *
161  * Property (2) upgrades the lock to an RCsc lock.
162  *
163  * Since most load-store architectures implement ACQUIRE with an smp_mb() after
164  * the LL/SC loop, they need no further barriers. Similarly all our TSO
165  * architectures imply an smp_mb() for each atomic instruction and equally don't
166  * need more.
167  *
168  * Architectures that can implement ACQUIRE better need to take care.
169  */
170 #ifndef smp_mb__after_spinlock
171 #define smp_mb__after_spinlock()        do { } while (0)
172 #endif
173 
174 #ifdef CONFIG_DEBUG_SPINLOCK
175  extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
176 #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
177  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
178  extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
179 #else
180 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
181 {
182         __acquire(lock);
183         arch_spin_lock(&lock->raw_lock);
184         mmiowb_spin_lock();
185 }
186 
187 #ifndef arch_spin_lock_flags
188 #define arch_spin_lock_flags(lock, flags)       arch_spin_lock(lock)
189 #endif
190 
191 static inline void
192 do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
193 {
194         __acquire(lock);
195         arch_spin_lock_flags(&lock->raw_lock, *flags);
196         mmiowb_spin_lock();
197 }
198 
199 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
200 {
201         int ret = arch_spin_trylock(&(lock)->raw_lock);
202 
203         if (ret)
204                 mmiowb_spin_lock();
205 
206         return ret;
207 }
208 
209 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
210 {
211         mmiowb_spin_unlock();
212         arch_spin_unlock(&lock->raw_lock);
213         __release(lock);
214 }
215 #endif
216 
217 /*
218  * Define the various spin_lock methods.  Note we define these
219  * regardless of whether CONFIG_SMP or CONFIG_PREEMPTION are set. The
220  * various methods are defined as nops in the case they are not
221  * required.
222  */
223 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
224 
225 #define raw_spin_lock(lock)     _raw_spin_lock(lock)
226 
227 #ifdef CONFIG_DEBUG_LOCK_ALLOC
228 # define raw_spin_lock_nested(lock, subclass) \
229         _raw_spin_lock_nested(lock, subclass)
230 
231 # define raw_spin_lock_nest_lock(lock, nest_lock)                       \
232          do {                                                           \
233                  typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
234                  _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
235          } while (0)
236 #else
237 /*
238  * Always evaluate the 'subclass' argument to avoid that the compiler
239  * warns about set-but-not-used variables when building with
240  * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1.
241  */
242 # define raw_spin_lock_nested(lock, subclass)           \
243         _raw_spin_lock(((void)(subclass), (lock)))
244 # define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
245 #endif
246 
247 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
248 
249 #define raw_spin_lock_irqsave(lock, flags)                      \
250         do {                                            \
251                 typecheck(unsigned long, flags);        \
252                 flags = _raw_spin_lock_irqsave(lock);   \
253         } while (0)
254 
255 #ifdef CONFIG_DEBUG_LOCK_ALLOC
256 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
257         do {                                                            \
258                 typecheck(unsigned long, flags);                        \
259                 flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
260         } while (0)
261 #else
262 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
263         do {                                                            \
264                 typecheck(unsigned long, flags);                        \
265                 flags = _raw_spin_lock_irqsave(lock);                   \
266         } while (0)
267 #endif
268 
269 #else
270 
271 #define raw_spin_lock_irqsave(lock, flags)              \
272         do {                                            \
273                 typecheck(unsigned long, flags);        \
274                 _raw_spin_lock_irqsave(lock, flags);    \
275         } while (0)
276 
277 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
278         raw_spin_lock_irqsave(lock, flags)
279 
280 #endif
281 
282 #define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
283 #define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
284 #define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
285 #define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
286 
287 #define raw_spin_unlock_irqrestore(lock, flags)         \
288         do {                                                    \
289                 typecheck(unsigned long, flags);                \
290                 _raw_spin_unlock_irqrestore(lock, flags);       \
291         } while (0)
292 #define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
293 
294 #define raw_spin_trylock_bh(lock) \
295         __cond_lock(lock, _raw_spin_trylock_bh(lock))
296 
297 #define raw_spin_trylock_irq(lock) \
298 ({ \
299         local_irq_disable(); \
300         raw_spin_trylock(lock) ? \
301         1 : ({ local_irq_enable(); 0;  }); \
302 })
303 
304 #define raw_spin_trylock_irqsave(lock, flags) \
305 ({ \
306         local_irq_save(flags); \
307         raw_spin_trylock(lock) ? \
308         1 : ({ local_irq_restore(flags); 0; }); \
309 })
310 
311 /* Include rwlock functions */
312 #include <linux/rwlock.h>
313 
314 /*
315  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
316  */
317 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
318 # include <linux/spinlock_api_smp.h>
319 #else
320 # include <linux/spinlock_api_up.h>
321 #endif
322 
323 /*
324  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
325  */
326 
327 static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
328 {
329         return &lock->rlock;
330 }
331 
332 #ifdef CONFIG_DEBUG_SPINLOCK
333 
334 # define spin_lock_init(lock)                                   \
335 do {                                                            \
336         static struct lock_class_key __key;                     \
337                                                                 \
338         __raw_spin_lock_init(spinlock_check(lock),              \
339                              #lock, &__key, LD_WAIT_CONFIG);    \
340 } while (0)
341 
342 #else
343 
344 # define spin_lock_init(_lock)                  \
345 do {                                            \
346         spinlock_check(_lock);                  \
347         *(_lock) = __SPIN_LOCK_UNLOCKED(_lock); \
348 } while (0)
349 
350 #endif
351 
352 static __always_inline void spin_lock(spinlock_t *lock)
353 {
354         raw_spin_lock(&lock->rlock);
355 }
356 
357 static __always_inline void spin_lock_bh(spinlock_t *lock)
358 {
359         raw_spin_lock_bh(&lock->rlock);
360 }
361 
362 static __always_inline int spin_trylock(spinlock_t *lock)
363 {
364         return raw_spin_trylock(&lock->rlock);
365 }
366 
367 #define spin_lock_nested(lock, subclass)                        \
368 do {                                                            \
369         raw_spin_lock_nested(spinlock_check(lock), subclass);   \
370 } while (0)
371 
372 #define spin_lock_nest_lock(lock, nest_lock)                            \
373 do {                                                                    \
374         raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
375 } while (0)
376 
377 static __always_inline void spin_lock_irq(spinlock_t *lock)
378 {
379         raw_spin_lock_irq(&lock->rlock);
380 }
381 
382 #define spin_lock_irqsave(lock, flags)                          \
383 do {                                                            \
384         raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
385 } while (0)
386 
387 #define spin_lock_irqsave_nested(lock, flags, subclass)                 \
388 do {                                                                    \
389         raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
390 } while (0)
391 
392 static __always_inline void spin_unlock(spinlock_t *lock)
393 {
394         raw_spin_unlock(&lock->rlock);
395 }
396 
397 static __always_inline void spin_unlock_bh(spinlock_t *lock)
398 {
399         raw_spin_unlock_bh(&lock->rlock);
400 }
401 
402 static __always_inline void spin_unlock_irq(spinlock_t *lock)
403 {
404         raw_spin_unlock_irq(&lock->rlock);
405 }
406 
407 static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
408 {
409         raw_spin_unlock_irqrestore(&lock->rlock, flags);
410 }
411 
412 static __always_inline int spin_trylock_bh(spinlock_t *lock)
413 {
414         return raw_spin_trylock_bh(&lock->rlock);
415 }
416 
417 static __always_inline int spin_trylock_irq(spinlock_t *lock)
418 {
419         return raw_spin_trylock_irq(&lock->rlock);
420 }
421 
422 #define spin_trylock_irqsave(lock, flags)                       \
423 ({                                                              \
424         raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
425 })
426 
427 /**
428  * spin_is_locked() - Check whether a spinlock is locked.
429  * @lock: Pointer to the spinlock.
430  *
431  * This function is NOT required to provide any memory ordering
432  * guarantees; it could be used for debugging purposes or, when
433  * additional synchronization is needed, accompanied with other
434  * constructs (memory barriers) enforcing the synchronization.
435  *
436  * Returns: 1 if @lock is locked, 0 otherwise.
437  *
438  * Note that the function only tells you that the spinlock is
439  * seen to be locked, not that it is locked on your CPU.
440  *
441  * Further, on CONFIG_SMP=n builds with CONFIG_DEBUG_SPINLOCK=n,
442  * the return value is always 0 (see include/linux/spinlock_up.h).
443  * Therefore you should not rely heavily on the return value.
444  */
445 static __always_inline int spin_is_locked(spinlock_t *lock)
446 {
447         return raw_spin_is_locked(&lock->rlock);
448 }
449 
450 static __always_inline int spin_is_contended(spinlock_t *lock)
451 {
452         return raw_spin_is_contended(&lock->rlock);
453 }
454 
455 #define assert_spin_locked(lock)        assert_raw_spin_locked(&(lock)->rlock)
456 
457 /*
458  * Pull the atomic_t declaration:
459  * (asm-mips/atomic.h needs above definitions)
460  */
461 #include <linux/atomic.h>
462 /**
463  * atomic_dec_and_lock - lock on reaching reference count zero
464  * @atomic: the atomic counter
465  * @lock: the spinlock in question
466  *
467  * Decrements @atomic by 1.  If the result is 0, returns true and locks
468  * @lock.  Returns false for all other cases.
469  */
470 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
471 #define atomic_dec_and_lock(atomic, lock) \
472                 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
473 
474 extern int _atomic_dec_and_lock_irqsave(atomic_t *atomic, spinlock_t *lock,
475                                         unsigned long *flags);
476 #define atomic_dec_and_lock_irqsave(atomic, lock, flags) \
477                 __cond_lock(lock, _atomic_dec_and_lock_irqsave(atomic, lock, &(flags)))
478 
479 int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *lock_mask,
480                              size_t max_size, unsigned int cpu_mult,
481                              gfp_t gfp, const char *name,
482                              struct lock_class_key *key);
483 
484 #define alloc_bucket_spinlocks(locks, lock_mask, max_size, cpu_mult, gfp)    \
485         ({                                                                   \
486                 static struct lock_class_key key;                            \
487                 int ret;                                                     \
488                                                                              \
489                 ret = __alloc_bucket_spinlocks(locks, lock_mask, max_size,   \
490                                                cpu_mult, gfp, #locks, &key); \
491                 ret;                                                         \
492         })
493 
494 void free_bucket_spinlocks(spinlock_t *locks);
495 
496 #endif /* __LINUX_SPINLOCK_H */
497 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp