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);
102 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
103 const char *file, int line);
104 void __mtx_unlock_sleep(volatile uintptr_t *c, int opts, const char *file,
107 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v);
108 void __mtx_unlock_sleep(volatile uintptr_t *c);
112 void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, uintptr_t tid,
113 int opts, const char *file, int line);
115 void __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file,
117 void __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file,
119 void __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
121 int __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts,
122 const char *file, int line);
123 void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts,
124 const char *file, int line);
125 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
126 void __mtx_assert(const volatile uintptr_t *c, int what, const char *file,
129 void thread_lock_flags_(struct thread *, int, const char *, int);
131 #define thread_lock(tdp) \
132 thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
133 #define thread_lock_flags(tdp, opt) \
134 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
135 #define thread_unlock(tdp) \
136 mtx_unlock_spin((tdp)->td_lock)
139 * Top-level macros to provide lock cookie once the actual mtx is passed.
140 * They will also prevent passing a malformed object to the mtx KPI by
141 * failing compilation as the mtx_lock reserved member will not be found.
143 #define mtx_init(m, n, t, o) \
144 _mtx_init(&(m)->mtx_lock, n, t, o)
145 #define mtx_destroy(m) \
146 _mtx_destroy(&(m)->mtx_lock)
147 #define mtx_trylock_flags_(m, o, f, l) \
148 _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l)
150 #define _mtx_lock_sleep(m, v, o, f, l) \
151 __mtx_lock_sleep(&(m)->mtx_lock, v, o, f, l)
152 #define _mtx_unlock_sleep(m, o, f, l) \
153 __mtx_unlock_sleep(&(m)->mtx_lock, o, f, l)
155 #define _mtx_lock_sleep(m, v, o, f, l) \
156 __mtx_lock_sleep(&(m)->mtx_lock, v)
157 #define _mtx_unlock_sleep(m, o, f, l) \
158 __mtx_unlock_sleep(&(m)->mtx_lock)
161 #define _mtx_lock_spin(m, v, t, o, f, l) \
162 _mtx_lock_spin_cookie(&(m)->mtx_lock, v, t, o, f, l)
164 #define _mtx_lock_flags(m, o, f, l) \
165 __mtx_lock_flags(&(m)->mtx_lock, o, f, l)
166 #define _mtx_unlock_flags(m, o, f, l) \
167 __mtx_unlock_flags(&(m)->mtx_lock, o, f, l)
168 #define _mtx_lock_spin_flags(m, o, f, l) \
169 __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l)
170 #define _mtx_trylock_spin_flags(m, o, f, l) \
171 __mtx_trylock_spin_flags(&(m)->mtx_lock, o, f, l)
172 #define _mtx_unlock_spin_flags(m, o, f, l) \
173 __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l)
174 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
175 #define _mtx_assert(m, w, f, l) \
176 __mtx_assert(&(m)->mtx_lock, w, f, l)
179 #define mtx_recurse lock_object.lo_data
181 /* Very simple operations on mtx_lock. */
183 /* Try to obtain mtx_lock once. */
184 #define _mtx_obtain_lock(mp, tid) \
185 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
187 #define _mtx_obtain_lock_fetch(mp, vp, tid) \
188 atomic_fcmpset_acq_ptr(&(mp)->mtx_lock, vp, (tid))
190 /* Try to release mtx_lock if it is unrecursed and uncontested. */
191 #define _mtx_release_lock(mp, tid) \
192 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
194 /* Release mtx_lock quickly, assuming we own it. */
195 #define _mtx_release_lock_quick(mp) \
196 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
199 * Full lock operations that are suitable to be inlined in non-debug
200 * kernels. If the lock cannot be acquired or released trivially then
201 * the work is deferred to another function.
204 /* Lock a normal mutex. */
205 #define __mtx_lock(mp, tid, opts, file, line) do { \
206 uintptr_t _tid = (uintptr_t)(tid); \
207 uintptr_t _v = MTX_UNOWNED; \
209 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__acquire) ||\
210 !_mtx_obtain_lock_fetch((mp), &_v, _tid))) \
211 _mtx_lock_sleep((mp), _v, (opts), (file), (line)); \
215 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
216 * turns out that function calls can be significantly expensive on
217 * some architectures). Since spin locks are not _too_ common,
218 * inlining this code is not too big a deal.
221 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
222 uintptr_t _tid = (uintptr_t)(tid); \
223 uintptr_t _v = MTX_UNOWNED; \
226 if (!_mtx_obtain_lock_fetch((mp), &_v, _tid)) \
227 _mtx_lock_spin((mp), _v, _tid, (opts), (file), (line)); \
229 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, \
230 mp, 0, 0, file, line); \
232 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
233 uintptr_t _tid = (uintptr_t)(tid); \
237 if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid))) {\
241 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, \
242 mp, 0, 0, file, line); \
248 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
249 uintptr_t _tid = (uintptr_t)(tid); \
252 if ((mp)->mtx_lock == _tid) \
253 (mp)->mtx_recurse++; \
255 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
256 (mp)->mtx_lock = _tid; \
259 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
260 uintptr_t _tid = (uintptr_t)(tid); \
264 if ((mp)->mtx_lock != MTX_UNOWNED) { \
268 (mp)->mtx_lock = _tid; \
275 /* Unlock a normal mutex. */
276 #define __mtx_unlock(mp, tid, opts, file, line) do { \
277 uintptr_t _tid = (uintptr_t)(tid); \
279 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__release) ||\
280 !_mtx_release_lock((mp), _tid))) \
281 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
285 * Unlock a spin mutex. For spinlocks, we can handle everything
286 * inline, as it's pretty simple and a function call would be too
287 * expensive (at least on some architectures). Since spin locks are
288 * not _too_ common, inlining this code is not too big a deal.
290 * Since we always perform a spinlock_enter() when attempting to acquire a
291 * spin lock, we need to always perform a matching spinlock_exit() when
292 * releasing a spin lock. This includes the recursion cases.
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 _mtx_release_lock_quick((mp)); \
305 #define __mtx_unlock_spin(mp) do { \
306 if (mtx_recursed((mp))) \
307 (mp)->mtx_recurse--; \
309 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp); \
310 (mp)->mtx_lock = MTX_UNOWNED; \
317 * Exported lock manipulation interface.
319 * mtx_lock(m) locks MTX_DEF mutex `m'
321 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
323 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
325 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
327 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
328 * and passes option flags `opts' to the "hard" function, if required.
329 * With these routines, it is possible to pass flags such as MTX_QUIET
330 * to the appropriate lock manipulation routines.
332 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
333 * it cannot. Rather, it returns 0 on failure and non-zero on success.
334 * It does NOT handle recursion as we assume that if a caller is properly
335 * using this part of the interface, he will know that the lock in question
338 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
339 * relevant option flags `opts.'
341 * mtx_trylock_spin(m) attempts to acquire MTX_SPIN mutex `m' but doesn't
342 * spin if it cannot. Rather, it returns 0 on failure and non-zero on
343 * success. It always returns failure for recursed lock attempts.
345 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
347 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
349 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
351 #define mtx_lock(m) mtx_lock_flags((m), 0)
352 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
353 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
354 #define mtx_trylock_spin(m) mtx_trylock_spin_flags((m), 0)
355 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
356 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
360 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
361 void mtx_pool_destroy(struct mtx_pool **poolp);
362 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
363 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
364 #define mtx_pool_lock(pool, ptr) \
365 mtx_lock(mtx_pool_find((pool), (ptr)))
366 #define mtx_pool_lock_spin(pool, ptr) \
367 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
368 #define mtx_pool_unlock(pool, ptr) \
369 mtx_unlock(mtx_pool_find((pool), (ptr)))
370 #define mtx_pool_unlock_spin(pool, ptr) \
371 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
374 * mtxpool_sleep is a general purpose pool of sleep mutexes.
376 extern struct mtx_pool *mtxpool_sleep;
379 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
381 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
382 #define mtx_lock_flags_(m, opts, file, line) \
383 _mtx_lock_flags((m), (opts), (file), (line))
384 #define mtx_unlock_flags_(m, opts, file, line) \
385 _mtx_unlock_flags((m), (opts), (file), (line))
386 #define mtx_lock_spin_flags_(m, opts, file, line) \
387 _mtx_lock_spin_flags((m), (opts), (file), (line))
388 #define mtx_trylock_spin_flags_(m, opts, file, line) \
389 _mtx_trylock_spin_flags((m), (opts), (file), (line))
390 #define mtx_unlock_spin_flags_(m, opts, file, line) \
391 _mtx_unlock_spin_flags((m), (opts), (file), (line))
392 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
393 #define mtx_lock_flags_(m, opts, file, line) \
394 __mtx_lock((m), curthread, (opts), (file), (line))
395 #define mtx_unlock_flags_(m, opts, file, line) \
396 __mtx_unlock((m), curthread, (opts), (file), (line))
397 #define mtx_lock_spin_flags_(m, opts, file, line) \
398 __mtx_lock_spin((m), curthread, (opts), (file), (line))
399 #define mtx_trylock_spin_flags_(m, opts, file, line) \
400 __mtx_trylock_spin((m), curthread, (opts), (file), (line))
401 #define mtx_unlock_spin_flags_(m, opts, file, line) \
402 __mtx_unlock_spin((m))
403 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
406 #define mtx_assert_(m, what, file, line) \
407 _mtx_assert((m), (what), (file), (line))
409 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
411 #else /* INVARIANTS */
412 #define mtx_assert_(m, what, file, line) (void)0
413 #define GIANT_REQUIRED
414 #endif /* INVARIANTS */
416 #define mtx_lock_flags(m, opts) \
417 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
418 #define mtx_unlock_flags(m, opts) \
419 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
420 #define mtx_lock_spin_flags(m, opts) \
421 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
422 #define mtx_unlock_spin_flags(m, opts) \
423 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
424 #define mtx_trylock_flags(m, opts) \
425 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
426 #define mtx_trylock_spin_flags(m, opts) \
427 mtx_trylock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
428 #define mtx_assert(m, what) \
429 mtx_assert_((m), (what), __FILE__, __LINE__)
431 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
432 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), \
433 tick_sbt * (timo), 0, C_HARDCLOCK)
435 #define MTX_READ_VALUE(m) ((m)->mtx_lock)
437 #define mtx_initialized(m) lock_initialized(&(m)->lock_object)
439 #define lv_mtx_owner(v) ((struct thread *)((v) & ~MTX_FLAGMASK))
441 #define mtx_owner(m) lv_mtx_owner(MTX_READ_VALUE(m))
443 #define mtx_owned(m) (mtx_owner(m) == curthread)
445 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
447 #define mtx_name(m) ((m)->lock_object.lo_name)
452 extern struct mtx Giant;
453 extern struct mtx blocked_lock;
456 * Giant lock manipulation and clean exit macros.
457 * Used to replace return with an exit Giant and return.
459 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
460 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
463 #define DROP_GIANT() \
466 WITNESS_SAVE_DECL(Giant); \
468 if (mtx_owned(&Giant)) { \
469 WITNESS_SAVE(&Giant.lock_object, Giant); \
470 for (_giantcnt = 0; mtx_owned(&Giant) && \
471 !SCHEDULER_STOPPED(); _giantcnt++) \
472 mtx_unlock(&Giant); \
475 #define PICKUP_GIANT() \
476 PARTIAL_PICKUP_GIANT(); \
479 #define PARTIAL_PICKUP_GIANT() \
480 mtx_assert(&Giant, MA_NOTOWNED); \
481 if (_giantcnt > 0) { \
482 while (_giantcnt--) \
484 WITNESS_RESTORE(&Giant.lock_object, Giant); \
494 #define MTX_SYSINIT(name, mtx, desc, opts) \
495 static struct mtx_args name##_args = { \
500 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
501 mtx_sysinit, &name##_args); \
502 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
503 _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
506 * The INVARIANTS-enabled mtx_assert() functionality.
508 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
509 * support as _mtx_assert() itself uses them and the latter implies that
510 * _mtx_assert() must build.
512 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
513 #define MA_OWNED LA_XLOCKED
514 #define MA_NOTOWNED LA_UNLOCKED
515 #define MA_RECURSED LA_RECURSED
516 #define MA_NOTRECURSED LA_NOTRECURSED
520 * Common lock type names.
522 #define MTX_NETWORK_LOCK "network driver"
525 #endif /* _SYS_MUTEX_H_ */