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
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. These functions should not be called directly by any
83 * code using the API. Their macros cover their functionality.
84 * Functions with a `_' suffix are the entrypoint for the common
85 * KPI covering both compat shims and fast path case. These can be
86 * used by consumers willing to pass options, file and line
87 * informations, in an option-independent way.
89 * [See below for descriptions]
92 void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
93 void mtx_destroy(struct mtx *m);
94 void mtx_sysinit(void *arg);
95 int mtx_trylock_flags_(struct mtx *m, int opts, const char *file,
97 void mutex_init(void);
98 void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts,
99 const char *file, int line);
100 void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
102 void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts,
103 const char *file, int line);
105 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
106 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
107 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
108 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
110 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
112 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
113 void _mtx_assert(const struct mtx *m, int what, const char *file, int line);
115 void thread_lock_flags_(struct thread *, int, const char *, int);
117 #define thread_lock(tdp) \
118 thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
119 #define thread_lock_flags(tdp, opt) \
120 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
121 #define thread_unlock(tdp) \
122 mtx_unlock_spin((tdp)->td_lock)
124 #define mtx_recurse lock_object.lo_data
126 /* Very simple operations on mtx_lock. */
128 /* Try to obtain mtx_lock once. */
129 #define _mtx_obtain_lock(mp, tid) \
130 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
132 /* Try to release mtx_lock if it is unrecursed and uncontested. */
133 #define _mtx_release_lock(mp, tid) \
134 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
136 /* Release mtx_lock quickly, assuming we own it. */
137 #define _mtx_release_lock_quick(mp) \
138 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
141 * Full lock operations that are suitable to be inlined in non-debug
142 * kernels. If the lock cannot be acquired or released trivially then
143 * the work is deferred to another function.
146 /* Lock a normal mutex. */
147 #define __mtx_lock(mp, tid, opts, file, line) do { \
148 uintptr_t _tid = (uintptr_t)(tid); \
150 if (!_mtx_obtain_lock((mp), _tid)) \
151 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
153 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \
154 mp, 0, 0, (file), (line)); \
158 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
159 * turns out that function calls can be significantly expensive on
160 * some architectures). Since spin locks are not _too_ common,
161 * inlining this code is not too big a deal.
164 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
165 uintptr_t _tid = (uintptr_t)(tid); \
168 if (!_mtx_obtain_lock((mp), _tid)) { \
169 if ((mp)->mtx_lock == _tid) \
170 (mp)->mtx_recurse++; \
172 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
174 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \
175 mp, 0, 0, (file), (line)); \
178 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
179 uintptr_t _tid = (uintptr_t)(tid); \
182 if ((mp)->mtx_lock == _tid) \
183 (mp)->mtx_recurse++; \
185 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
186 (mp)->mtx_lock = _tid; \
191 /* Unlock a normal mutex. */
192 #define __mtx_unlock(mp, tid, opts, file, line) do { \
193 uintptr_t _tid = (uintptr_t)(tid); \
195 if (!_mtx_release_lock((mp), _tid)) \
196 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
200 * Unlock a spin mutex. For spinlocks, we can handle everything
201 * inline, as it's pretty simple and a function call would be too
202 * expensive (at least on some architectures). Since spin locks are
203 * not _too_ common, inlining this code is not too big a deal.
205 * Since we always perform a spinlock_enter() when attempting to acquire a
206 * spin lock, we need to always perform a matching spinlock_exit() when
207 * releasing a spin lock. This includes the recursion cases.
210 #define __mtx_unlock_spin(mp) do { \
211 if (mtx_recursed((mp))) \
212 (mp)->mtx_recurse--; \
214 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
216 _mtx_release_lock_quick((mp)); \
221 #define __mtx_unlock_spin(mp) do { \
222 if (mtx_recursed((mp))) \
223 (mp)->mtx_recurse--; \
225 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
227 (mp)->mtx_lock = MTX_UNOWNED; \
234 * Exported lock manipulation interface.
236 * mtx_lock(m) locks MTX_DEF mutex `m'
238 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
240 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
242 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
244 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
245 * and passes option flags `opts' to the "hard" function, if required.
246 * With these routines, it is possible to pass flags such as MTX_QUIET
247 * to the appropriate lock manipulation routines.
249 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
250 * it cannot. Rather, it returns 0 on failure and non-zero on success.
251 * It does NOT handle recursion as we assume that if a caller is properly
252 * using this part of the interface, he will know that the lock in question
255 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
256 * relevant option flags `opts.'
258 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
260 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
262 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
264 #define mtx_lock(m) mtx_lock_flags((m), 0)
265 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
266 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
267 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
268 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
272 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
273 void mtx_pool_destroy(struct mtx_pool **poolp);
274 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
275 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
276 #define mtx_pool_lock(pool, ptr) \
277 mtx_lock(mtx_pool_find((pool), (ptr)))
278 #define mtx_pool_lock_spin(pool, ptr) \
279 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
280 #define mtx_pool_unlock(pool, ptr) \
281 mtx_unlock(mtx_pool_find((pool), (ptr)))
282 #define mtx_pool_unlock_spin(pool, ptr) \
283 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
286 * mtxpool_lockbuilder is a pool of sleep locks that is not witness
287 * checked and should only be used for building higher level locks.
289 * mtxpool_sleep is a general purpose pool of sleep mutexes.
291 extern struct mtx_pool *mtxpool_lockbuilder;
292 extern struct mtx_pool *mtxpool_sleep;
295 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
297 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
298 #define mtx_lock_flags_(m, opts, file, line) \
299 _mtx_lock_flags((m), (opts), (file), (line))
300 #define mtx_unlock_flags_(m, opts, file, line) \
301 _mtx_unlock_flags((m), (opts), (file), (line))
302 #define mtx_lock_spin_flags_(m, opts, file, line) \
303 _mtx_lock_spin_flags((m), (opts), (file), (line))
304 #define mtx_unlock_spin_flags_(m, opts, file, line) \
305 _mtx_unlock_spin_flags((m), (opts), (file), (line))
306 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
307 #define mtx_lock_flags_(m, opts, file, line) \
308 __mtx_lock((m), curthread, (opts), (file), (line))
309 #define mtx_unlock_flags_(m, opts, file, line) \
310 __mtx_unlock((m), curthread, (opts), (file), (line))
311 #define mtx_lock_spin_flags_(m, opts, file, line) \
312 __mtx_lock_spin((m), curthread, (opts), (file), (line))
313 #define mtx_unlock_spin_flags_(m, opts, file, line) \
314 __mtx_unlock_spin((m))
315 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
318 #define mtx_assert_(m, what, file, line) \
319 _mtx_assert((m), (what), (file), (line))
321 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
323 #else /* INVARIANTS */
324 #define mtx_assert_(m, what, file, line) (void)0
325 #define GIANT_REQUIRED
326 #endif /* INVARIANTS */
328 #define mtx_lock_flags(m, opts) \
329 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
330 #define mtx_unlock_flags(m, opts) \
331 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
332 #define mtx_lock_spin_flags(m, opts) \
333 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
334 #define mtx_unlock_spin_flags(m, opts) \
335 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
336 #define mtx_trylock_flags(m, opts) \
337 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
338 #define mtx_assert(m, what) \
339 mtx_assert_((m), (what), __FILE__, __LINE__)
341 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
342 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo))
344 #define mtx_initialized(m) lock_initalized(&(m)->lock_object)
346 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread)
348 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
350 #define mtx_name(m) ((m)->lock_object.lo_name)
355 extern struct mtx Giant;
356 extern struct mtx blocked_lock;
359 * Giant lock manipulation and clean exit macros.
360 * Used to replace return with an exit Giant and return.
362 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
363 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
366 #define DROP_GIANT() \
369 WITNESS_SAVE_DECL(Giant); \
371 if (mtx_owned(&Giant)) { \
372 WITNESS_SAVE(&Giant.lock_object, Giant); \
373 for (_giantcnt = 0; mtx_owned(&Giant) && \
374 !SCHEDULER_STOPPED(); _giantcnt++) \
375 mtx_unlock(&Giant); \
378 #define PICKUP_GIANT() \
379 PARTIAL_PICKUP_GIANT(); \
382 #define PARTIAL_PICKUP_GIANT() \
383 mtx_assert(&Giant, MA_NOTOWNED); \
384 if (_giantcnt > 0) { \
385 while (_giantcnt--) \
387 WITNESS_RESTORE(&Giant.lock_object, Giant); \
391 #define UGAR(rval) do { \
393 mtx_unlock(&Giant); \
403 #define MTX_SYSINIT(name, mtx, desc, opts) \
404 static struct mtx_args name##_args = { \
409 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
410 mtx_sysinit, &name##_args); \
411 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
415 * The INVARIANTS-enabled mtx_assert() functionality.
417 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
418 * support as _mtx_assert() itself uses them and the latter implies that
419 * _mtx_assert() must build.
421 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
422 #define MA_OWNED LA_XLOCKED
423 #define MA_NOTOWNED LA_UNLOCKED
424 #define MA_RECURSED LA_RECURSED
425 #define MA_NOTRECURSED LA_NOTRECURSED
429 * Common lock type names.
431 #define MTX_NETWORK_LOCK "network driver"
434 #endif /* _SYS_MUTEX_H_ */