2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
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12 * 3. Berkeley Software Design Inc's name may not be used to endorse or
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16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
35 #include <sys/queue.h>
36 #include <sys/_lock.h>
37 #include <sys/_mutex.h>
41 #include <sys/lock_profile.h>
42 #include <sys/lockstat.h>
43 #include <machine/atomic.h>
44 #include <machine/cpufunc.h>
47 * Mutex types and options passed to mtx_init(). MTX_QUIET and MTX_DUPOK
48 * can also be passed in.
50 #define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
51 #define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
52 #define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
53 #define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
54 #define MTX_NOPROFILE 0x00000020 /* Don't profile this lock */
55 #define MTX_NEW 0x00000040 /* Don't check for double-init */
58 * Option flags passed to certain lock/unlock routines, through the use
59 * of corresponding mtx_{lock,unlock}_flags() interface macros.
61 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
62 #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */
65 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
66 * with the exception of MTX_UNOWNED, applies to spin locks.
68 #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
69 #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
70 #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
71 #define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED)
74 * Value stored in mutex->mtx_lock to denote a destroyed mutex.
76 #define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED)
81 * NOTE: Functions prepended with `_' (underscore) are exported to other parts
82 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
83 * and LOCK_LINE or for hiding the lock cookie crunching to the
84 * consumers. These functions should not be called directly by any
85 * code using the API. Their macros cover their functionality.
86 * Functions with a `_' suffix are the entrypoint for the common
87 * KPI covering both compat shims and fast path case. These can be
88 * used by consumers willing to pass options, file and line
89 * informations, in an option-independent way.
91 * [See below for descriptions]
94 void _mtx_init(volatile uintptr_t *c, const char *name, const char *type,
96 void _mtx_destroy(volatile uintptr_t *c);
97 void mtx_sysinit(void *arg);
98 int _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file,
100 void mutex_init(void);
101 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, uintptr_t tid,
102 int opts, const char *file, int line);
103 void __mtx_unlock_sleep(volatile uintptr_t *c, int opts, const char *file,
106 void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, uintptr_t tid,
107 int opts, const char *file, int line);
109 void __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file,
111 void __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file,
113 void __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
115 int __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts,
116 const char *file, int line);
117 void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts,
118 const char *file, int line);
119 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
120 void __mtx_assert(const volatile uintptr_t *c, int what, const char *file,
123 void thread_lock_flags_(struct thread *, int, const char *, int);
125 #define thread_lock(tdp) \
126 thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
127 #define thread_lock_flags(tdp, opt) \
128 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
129 #define thread_unlock(tdp) \
130 mtx_unlock_spin((tdp)->td_lock)
133 * Top-level macros to provide lock cookie once the actual mtx is passed.
134 * They will also prevent passing a malformed object to the mtx KPI by
135 * failing compilation as the mtx_lock reserved member will not be found.
137 #define mtx_init(m, n, t, o) \
138 _mtx_init(&(m)->mtx_lock, n, t, o)
139 #define mtx_destroy(m) \
140 _mtx_destroy(&(m)->mtx_lock)
141 #define mtx_trylock_flags_(m, o, f, l) \
142 _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l)
143 #define _mtx_lock_sleep(m, v, t, o, f, l) \
144 __mtx_lock_sleep(&(m)->mtx_lock, v, t, o, f, l)
145 #define _mtx_unlock_sleep(m, o, f, l) \
146 __mtx_unlock_sleep(&(m)->mtx_lock, o, f, l)
148 #define _mtx_lock_spin(m, v, t, o, f, l) \
149 _mtx_lock_spin_cookie(&(m)->mtx_lock, v, t, o, f, l)
151 #define _mtx_lock_flags(m, o, f, l) \
152 __mtx_lock_flags(&(m)->mtx_lock, o, f, l)
153 #define _mtx_unlock_flags(m, o, f, l) \
154 __mtx_unlock_flags(&(m)->mtx_lock, o, f, l)
155 #define _mtx_lock_spin_flags(m, o, f, l) \
156 __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l)
157 #define _mtx_trylock_spin_flags(m, o, f, l) \
158 __mtx_trylock_spin_flags(&(m)->mtx_lock, o, f, l)
159 #define _mtx_unlock_spin_flags(m, o, f, l) \
160 __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l)
161 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
162 #define _mtx_assert(m, w, f, l) \
163 __mtx_assert(&(m)->mtx_lock, w, f, l)
166 #define mtx_recurse lock_object.lo_data
168 /* Very simple operations on mtx_lock. */
170 /* Try to obtain mtx_lock once. */
171 #define _mtx_obtain_lock(mp, tid) \
172 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
174 #define _mtx_obtain_lock_fetch(mp, vp, tid) \
175 atomic_fcmpset_rel_ptr(&(mp)->mtx_lock, vp, (tid))
177 /* Try to release mtx_lock if it is unrecursed and uncontested. */
178 #define _mtx_release_lock(mp, tid) \
179 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
181 /* Release mtx_lock quickly, assuming we own it. */
182 #define _mtx_release_lock_quick(mp) \
183 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
186 * Full lock operations that are suitable to be inlined in non-debug
187 * kernels. If the lock cannot be acquired or released trivially then
188 * the work is deferred to another function.
191 /* Lock a normal mutex. */
192 #define __mtx_lock(mp, tid, opts, file, line) do { \
193 uintptr_t _tid = (uintptr_t)(tid); \
194 uintptr_t _v = MTX_UNOWNED; \
196 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__acquire) ||\
197 !_mtx_obtain_lock_fetch((mp), &_v, _tid))) \
198 _mtx_lock_sleep((mp), _v, _tid, (opts), (file), (line));\
202 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
203 * turns out that function calls can be significantly expensive on
204 * some architectures). Since spin locks are not _too_ common,
205 * inlining this code is not too big a deal.
208 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
209 uintptr_t _tid = (uintptr_t)(tid); \
210 uintptr_t _v = MTX_UNOWNED; \
213 if (!_mtx_obtain_lock_fetch((mp), &_v, _tid)) { \
215 (mp)->mtx_recurse++; \
217 _mtx_lock_spin((mp), _v, _tid, (opts), (file), (line));\
219 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, \
220 mp, 0, 0, file, line); \
222 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
223 uintptr_t _tid = (uintptr_t)(tid); \
227 if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid))) {\
231 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, \
232 mp, 0, 0, file, line); \
238 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
239 uintptr_t _tid = (uintptr_t)(tid); \
242 if ((mp)->mtx_lock == _tid) \
243 (mp)->mtx_recurse++; \
245 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
246 (mp)->mtx_lock = _tid; \
249 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
250 uintptr_t _tid = (uintptr_t)(tid); \
254 if ((mp)->mtx_lock != MTX_UNOWNED) { \
258 (mp)->mtx_lock = _tid; \
265 /* Unlock a normal mutex. */
266 #define __mtx_unlock(mp, tid, opts, file, line) do { \
267 uintptr_t _tid = (uintptr_t)(tid); \
269 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__release) ||\
270 !_mtx_release_lock((mp), _tid))) \
271 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
275 * Unlock a spin mutex. For spinlocks, we can handle everything
276 * inline, as it's pretty simple and a function call would be too
277 * expensive (at least on some architectures). Since spin locks are
278 * not _too_ common, inlining this code is not too big a deal.
280 * Since we always perform a spinlock_enter() when attempting to acquire a
281 * spin lock, we need to always perform a matching spinlock_exit() when
282 * releasing a spin lock. This includes the recursion cases.
285 #define __mtx_unlock_spin(mp) do { \
286 if (mtx_recursed((mp))) \
287 (mp)->mtx_recurse--; \
289 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp); \
290 _mtx_release_lock_quick((mp)); \
295 #define __mtx_unlock_spin(mp) do { \
296 if (mtx_recursed((mp))) \
297 (mp)->mtx_recurse--; \
299 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp); \
300 (mp)->mtx_lock = MTX_UNOWNED; \
307 * Exported lock manipulation interface.
309 * mtx_lock(m) locks MTX_DEF mutex `m'
311 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
313 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
315 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
317 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
318 * and passes option flags `opts' to the "hard" function, if required.
319 * With these routines, it is possible to pass flags such as MTX_QUIET
320 * to the appropriate lock manipulation routines.
322 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
323 * it cannot. Rather, it returns 0 on failure and non-zero on success.
324 * It does NOT handle recursion as we assume that if a caller is properly
325 * using this part of the interface, he will know that the lock in question
328 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
329 * relevant option flags `opts.'
331 * mtx_trylock_spin(m) attempts to acquire MTX_SPIN mutex `m' but doesn't
332 * spin if it cannot. Rather, it returns 0 on failure and non-zero on
333 * success. It always returns failure for recursed lock attempts.
335 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
337 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
339 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
341 #define mtx_lock(m) mtx_lock_flags((m), 0)
342 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
343 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
344 #define mtx_trylock_spin(m) mtx_trylock_spin_flags((m), 0)
345 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
346 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
350 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
351 void mtx_pool_destroy(struct mtx_pool **poolp);
352 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
353 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
354 #define mtx_pool_lock(pool, ptr) \
355 mtx_lock(mtx_pool_find((pool), (ptr)))
356 #define mtx_pool_lock_spin(pool, ptr) \
357 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
358 #define mtx_pool_unlock(pool, ptr) \
359 mtx_unlock(mtx_pool_find((pool), (ptr)))
360 #define mtx_pool_unlock_spin(pool, ptr) \
361 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
364 * mtxpool_sleep is a general purpose pool of sleep mutexes.
366 extern struct mtx_pool *mtxpool_sleep;
369 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
371 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
372 #define mtx_lock_flags_(m, opts, file, line) \
373 _mtx_lock_flags((m), (opts), (file), (line))
374 #define mtx_unlock_flags_(m, opts, file, line) \
375 _mtx_unlock_flags((m), (opts), (file), (line))
376 #define mtx_lock_spin_flags_(m, opts, file, line) \
377 _mtx_lock_spin_flags((m), (opts), (file), (line))
378 #define mtx_trylock_spin_flags_(m, opts, file, line) \
379 _mtx_trylock_spin_flags((m), (opts), (file), (line))
380 #define mtx_unlock_spin_flags_(m, opts, file, line) \
381 _mtx_unlock_spin_flags((m), (opts), (file), (line))
382 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
383 #define mtx_lock_flags_(m, opts, file, line) \
384 __mtx_lock((m), curthread, (opts), (file), (line))
385 #define mtx_unlock_flags_(m, opts, file, line) \
386 __mtx_unlock((m), curthread, (opts), (file), (line))
387 #define mtx_lock_spin_flags_(m, opts, file, line) \
388 __mtx_lock_spin((m), curthread, (opts), (file), (line))
389 #define mtx_trylock_spin_flags_(m, opts, file, line) \
390 __mtx_trylock_spin((m), curthread, (opts), (file), (line))
391 #define mtx_unlock_spin_flags_(m, opts, file, line) \
392 __mtx_unlock_spin((m))
393 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
396 #define mtx_assert_(m, what, file, line) \
397 _mtx_assert((m), (what), (file), (line))
399 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
401 #else /* INVARIANTS */
402 #define mtx_assert_(m, what, file, line) (void)0
403 #define GIANT_REQUIRED
404 #endif /* INVARIANTS */
406 #define mtx_lock_flags(m, opts) \
407 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
408 #define mtx_unlock_flags(m, opts) \
409 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
410 #define mtx_lock_spin_flags(m, opts) \
411 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
412 #define mtx_unlock_spin_flags(m, opts) \
413 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
414 #define mtx_trylock_flags(m, opts) \
415 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
416 #define mtx_trylock_spin_flags(m, opts) \
417 mtx_trylock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
418 #define mtx_assert(m, what) \
419 mtx_assert_((m), (what), __FILE__, __LINE__)
421 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
422 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), \
423 tick_sbt * (timo), 0, C_HARDCLOCK)
425 #define MTX_READ_VALUE(m) ((m)->mtx_lock)
427 #define mtx_initialized(m) lock_initialized(&(m)->lock_object)
429 #define lv_mtx_owner(v) ((struct thread *)((v) & ~MTX_FLAGMASK))
431 #define mtx_owner(m) lv_mtx_owner(MTX_READ_VALUE(m))
433 #define mtx_owned(m) (mtx_owner(m) == curthread)
435 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
437 #define mtx_name(m) ((m)->lock_object.lo_name)
442 extern struct mtx Giant;
443 extern struct mtx blocked_lock;
446 * Giant lock manipulation and clean exit macros.
447 * Used to replace return with an exit Giant and return.
449 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
450 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
453 #define DROP_GIANT() \
456 WITNESS_SAVE_DECL(Giant); \
458 if (mtx_owned(&Giant)) { \
459 WITNESS_SAVE(&Giant.lock_object, Giant); \
460 for (_giantcnt = 0; mtx_owned(&Giant) && \
461 !SCHEDULER_STOPPED(); _giantcnt++) \
462 mtx_unlock(&Giant); \
465 #define PICKUP_GIANT() \
466 PARTIAL_PICKUP_GIANT(); \
469 #define PARTIAL_PICKUP_GIANT() \
470 mtx_assert(&Giant, MA_NOTOWNED); \
471 if (_giantcnt > 0) { \
472 while (_giantcnt--) \
474 WITNESS_RESTORE(&Giant.lock_object, Giant); \
484 #define MTX_SYSINIT(name, mtx, desc, opts) \
485 static struct mtx_args name##_args = { \
490 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
491 mtx_sysinit, &name##_args); \
492 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
493 _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
496 * The INVARIANTS-enabled mtx_assert() functionality.
498 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
499 * support as _mtx_assert() itself uses them and the latter implies that
500 * _mtx_assert() must build.
502 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
503 #define MA_OWNED LA_XLOCKED
504 #define MA_NOTOWNED LA_UNLOCKED
505 #define MA_RECURSED LA_RECURSED
506 #define MA_NOTRECURSED LA_NOTRECURSED
510 * Common lock type names.
512 #define MTX_NETWORK_LOCK "network driver"
515 #endif /* _SYS_MUTEX_H_ */