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
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12 * 3. Berkeley Software Design Inc's name may not be used to endorse or
13 * promote products derived from this software without specific prior
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 */
57 * Option flags passed to certain lock/unlock routines, through the use
58 * of corresponding mtx_{lock,unlock}_flags() interface macros.
60 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
61 #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */
64 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
65 * with the exception of MTX_UNOWNED, applies to spin locks.
67 #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
68 #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
69 #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
70 #define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED)
73 * Value stored in mutex->mtx_lock to denote a destroyed mutex.
75 #define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED)
80 * NOTE: Functions prepended with `_' (underscore) are exported to other parts
81 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
82 * and LOCK_LINE or for hiding the lock cookie crunching to the
83 * consumers. These functions should not be called directly by any
84 * code using the API. Their macros cover their functionality.
85 * Functions with a `_' suffix are the entrypoint for the common
86 * KPI covering both compat shims and fast path case. These can be
87 * used by consumers willing to pass options, file and line
88 * informations, in an option-independent way.
90 * [See below for descriptions]
93 void _mtx_init(volatile uintptr_t *c, const char *name, const char *type,
95 void _mtx_destroy(volatile uintptr_t *c);
96 void mtx_sysinit(void *arg);
97 int _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file,
99 void mutex_init(void);
100 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t tid, int opts,
101 const char *file, int line);
102 void __mtx_unlock_sleep(volatile uintptr_t *c, int opts, const char *file,
105 void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts,
106 const char *file, int line);
108 void __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file,
110 void __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file,
112 void __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
114 int __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts,
115 const char *file, int line);
116 void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts,
117 const char *file, int line);
118 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
119 void __mtx_assert(const volatile uintptr_t *c, int what, const char *file,
122 void thread_lock_flags_(struct thread *, int, const char *, int);
124 #define thread_lock(tdp) \
125 thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
126 #define thread_lock_flags(tdp, opt) \
127 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
128 #define thread_unlock(tdp) \
129 mtx_unlock_spin((tdp)->td_lock)
132 * Top-level macros to provide lock cookie once the actual mtx is passed.
133 * They will also prevent passing a malformed object to the mtx KPI by
134 * failing compilation as the mtx_lock reserved member will not be found.
136 #define mtx_init(m, n, t, o) \
137 _mtx_init(&(m)->mtx_lock, n, t, o)
138 #define mtx_destroy(m) \
139 _mtx_destroy(&(m)->mtx_lock)
140 #define mtx_trylock_flags_(m, o, f, l) \
141 _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l)
142 #define _mtx_lock_sleep(m, t, o, f, l) \
143 __mtx_lock_sleep(&(m)->mtx_lock, t, o, f, l)
144 #define _mtx_unlock_sleep(m, o, f, l) \
145 __mtx_unlock_sleep(&(m)->mtx_lock, o, f, l)
147 #define _mtx_lock_spin(m, t, o, f, l) \
148 _mtx_lock_spin_cookie(&(m)->mtx_lock, t, o, f, l)
150 #define _mtx_lock_flags(m, o, f, l) \
151 __mtx_lock_flags(&(m)->mtx_lock, o, f, l)
152 #define _mtx_unlock_flags(m, o, f, l) \
153 __mtx_unlock_flags(&(m)->mtx_lock, o, f, l)
154 #define _mtx_lock_spin_flags(m, o, f, l) \
155 __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l)
156 #define _mtx_trylock_spin_flags(m, o, f, l) \
157 __mtx_trylock_spin_flags(&(m)->mtx_lock, o, f, l)
158 #define _mtx_unlock_spin_flags(m, o, f, l) \
159 __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l)
160 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
161 #define _mtx_assert(m, w, f, l) \
162 __mtx_assert(&(m)->mtx_lock, w, f, l)
165 #define mtx_recurse lock_object.lo_data
167 /* Very simple operations on mtx_lock. */
169 /* Try to obtain mtx_lock once. */
170 #define _mtx_obtain_lock(mp, tid) \
171 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
173 /* Try to release mtx_lock if it is unrecursed and uncontested. */
174 #define _mtx_release_lock(mp, tid) \
175 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
177 /* Release mtx_lock quickly, assuming we own it. */
178 #define _mtx_release_lock_quick(mp) \
179 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
182 * Full lock operations that are suitable to be inlined in non-debug
183 * kernels. If the lock cannot be acquired or released trivially then
184 * the work is deferred to another function.
187 /* Lock a normal mutex. */
188 #define __mtx_lock(mp, tid, opts, file, line) do { \
189 uintptr_t _tid = (uintptr_t)(tid); \
191 if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid)))\
192 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
194 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \
195 mp, 0, 0, (file), (line)); \
199 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
200 * turns out that function calls can be significantly expensive on
201 * some architectures). Since spin locks are not _too_ common,
202 * inlining this code is not too big a deal.
205 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
206 uintptr_t _tid = (uintptr_t)(tid); \
209 if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid))) {\
210 if ((mp)->mtx_lock == _tid) \
211 (mp)->mtx_recurse++; \
213 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
215 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \
216 mp, 0, 0, (file), (line)); \
218 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
219 uintptr_t _tid = (uintptr_t)(tid); \
223 if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid))) {\
227 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \
228 mp, 0, 0, file, line); \
234 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
235 uintptr_t _tid = (uintptr_t)(tid); \
238 if ((mp)->mtx_lock == _tid) \
239 (mp)->mtx_recurse++; \
241 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
242 (mp)->mtx_lock = _tid; \
245 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__ ({ \
246 uintptr_t _tid = (uintptr_t)(tid); \
250 if ((mp)->mtx_lock != MTX_UNOWNED) { \
254 (mp)->mtx_lock = _tid; \
261 /* Unlock a normal mutex. */
262 #define __mtx_unlock(mp, tid, opts, file, line) do { \
263 uintptr_t _tid = (uintptr_t)(tid); \
265 if ((mp)->mtx_lock != _tid || !_mtx_release_lock((mp), _tid)) \
266 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
270 * Unlock a spin mutex. For spinlocks, we can handle everything
271 * inline, as it's pretty simple and a function call would be too
272 * expensive (at least on some architectures). Since spin locks are
273 * not _too_ common, inlining this code is not too big a deal.
275 * Since we always perform a spinlock_enter() when attempting to acquire a
276 * spin lock, we need to always perform a matching spinlock_exit() when
277 * releasing a spin lock. This includes the recursion cases.
280 #define __mtx_unlock_spin(mp) do { \
281 if (mtx_recursed((mp))) \
282 (mp)->mtx_recurse--; \
284 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
286 _mtx_release_lock_quick((mp)); \
291 #define __mtx_unlock_spin(mp) do { \
292 if (mtx_recursed((mp))) \
293 (mp)->mtx_recurse--; \
295 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
297 (mp)->mtx_lock = MTX_UNOWNED; \
304 * Exported lock manipulation interface.
306 * mtx_lock(m) locks MTX_DEF mutex `m'
308 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
310 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
312 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
314 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
315 * and passes option flags `opts' to the "hard" function, if required.
316 * With these routines, it is possible to pass flags such as MTX_QUIET
317 * to the appropriate lock manipulation routines.
319 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
320 * it cannot. Rather, it returns 0 on failure and non-zero on success.
321 * It does NOT handle recursion as we assume that if a caller is properly
322 * using this part of the interface, he will know that the lock in question
325 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
326 * relevant option flags `opts.'
328 * mtx_trylock_spin(m) attempts to acquire MTX_SPIN mutex `m' but doesn't
329 * spin if it cannot. Rather, it returns 0 on failure and non-zero on
330 * success. It always returns failure for recursed lock attempts.
332 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
334 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
336 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
338 #define mtx_lock(m) mtx_lock_flags((m), 0)
339 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
340 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
341 #define mtx_trylock_spin(m) mtx_trylock_spin_flags((m), 0)
342 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
343 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
347 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
348 void mtx_pool_destroy(struct mtx_pool **poolp);
349 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
350 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
351 #define mtx_pool_lock(pool, ptr) \
352 mtx_lock(mtx_pool_find((pool), (ptr)))
353 #define mtx_pool_lock_spin(pool, ptr) \
354 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
355 #define mtx_pool_unlock(pool, ptr) \
356 mtx_unlock(mtx_pool_find((pool), (ptr)))
357 #define mtx_pool_unlock_spin(pool, ptr) \
358 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
361 * mtxpool_lockbuilder is a pool of sleep locks that is not witness
362 * checked and should only be used for building higher level locks.
364 * mtxpool_sleep is a general purpose pool of sleep mutexes.
366 extern struct mtx_pool *mtxpool_lockbuilder;
367 extern struct mtx_pool *mtxpool_sleep;
370 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
372 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
373 #define mtx_lock_flags_(m, opts, file, line) \
374 _mtx_lock_flags((m), (opts), (file), (line))
375 #define mtx_unlock_flags_(m, opts, file, line) \
376 _mtx_unlock_flags((m), (opts), (file), (line))
377 #define mtx_lock_spin_flags_(m, opts, file, line) \
378 _mtx_lock_spin_flags((m), (opts), (file), (line))
379 #define mtx_trylock_spin_flags_(m, opts, file, line) \
380 _mtx_trylock_spin_flags((m), (opts), (file), (line))
381 #define mtx_unlock_spin_flags_(m, opts, file, line) \
382 _mtx_unlock_spin_flags((m), (opts), (file), (line))
383 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
384 #define mtx_lock_flags_(m, opts, file, line) \
385 __mtx_lock((m), curthread, (opts), (file), (line))
386 #define mtx_unlock_flags_(m, opts, file, line) \
387 __mtx_unlock((m), curthread, (opts), (file), (line))
388 #define mtx_lock_spin_flags_(m, opts, file, line) \
389 __mtx_lock_spin((m), curthread, (opts), (file), (line))
390 #define mtx_trylock_spin_flags_(m, opts, file, line) \
391 __mtx_trylock_spin((m), curthread, (opts), (file), (line))
392 #define mtx_unlock_spin_flags_(m, opts, file, line) \
393 __mtx_unlock_spin((m))
394 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
397 #define mtx_assert_(m, what, file, line) \
398 _mtx_assert((m), (what), (file), (line))
400 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
402 #else /* INVARIANTS */
403 #define mtx_assert_(m, what, file, line) (void)0
404 #define GIANT_REQUIRED
405 #endif /* INVARIANTS */
407 #define mtx_lock_flags(m, opts) \
408 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
409 #define mtx_unlock_flags(m, opts) \
410 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
411 #define mtx_lock_spin_flags(m, opts) \
412 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
413 #define mtx_unlock_spin_flags(m, opts) \
414 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
415 #define mtx_trylock_flags(m, opts) \
416 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
417 #define mtx_trylock_spin_flags(m, opts) \
418 mtx_trylock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
419 #define mtx_assert(m, what) \
420 mtx_assert_((m), (what), __FILE__, __LINE__)
422 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
423 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), \
424 tick_sbt * (timo), 0, C_HARDCLOCK)
426 #define mtx_initialized(m) lock_initalized(&(m)->lock_object)
428 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread)
430 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
432 #define mtx_name(m) ((m)->lock_object.lo_name)
437 extern struct mtx Giant;
438 extern struct mtx blocked_lock;
441 * Giant lock manipulation and clean exit macros.
442 * Used to replace return with an exit Giant and return.
444 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
445 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
448 #define DROP_GIANT() \
451 WITNESS_SAVE_DECL(Giant); \
453 if (mtx_owned(&Giant)) { \
454 WITNESS_SAVE(&Giant.lock_object, Giant); \
455 for (_giantcnt = 0; mtx_owned(&Giant) && \
456 !SCHEDULER_STOPPED(); _giantcnt++) \
457 mtx_unlock(&Giant); \
460 #define PICKUP_GIANT() \
461 PARTIAL_PICKUP_GIANT(); \
464 #define PARTIAL_PICKUP_GIANT() \
465 mtx_assert(&Giant, MA_NOTOWNED); \
466 if (_giantcnt > 0) { \
467 while (_giantcnt--) \
469 WITNESS_RESTORE(&Giant.lock_object, Giant); \
479 #define MTX_SYSINIT(name, mtx, desc, opts) \
480 static struct mtx_args name##_args = { \
485 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
486 mtx_sysinit, &name##_args); \
487 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
488 _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
491 * The INVARIANTS-enabled mtx_assert() functionality.
493 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
494 * support as _mtx_assert() itself uses them and the latter implies that
495 * _mtx_assert() must build.
497 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
498 #define MA_OWNED LA_XLOCKED
499 #define MA_NOTOWNED LA_UNLOCKED
500 #define MA_RECURSED LA_RECURSED
501 #define MA_NOTRECURSED LA_NOTRECURSED
505 * Common lock type names.
507 #define MTX_NETWORK_LOCK "network driver"
510 #endif /* _SYS_MUTEX_H_ */