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
11 * documentation and/or other materials provided with the distribution.
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)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.
85 * [See below for descriptions]
88 void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
89 void mtx_destroy(struct mtx *m);
90 void mtx_sysinit(void *arg);
91 void mutex_init(void);
92 void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts,
93 const char *file, int line);
94 void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
96 void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts,
97 const char *file, int line);
99 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
100 int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
101 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
102 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
103 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
105 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
107 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
108 void _mtx_assert(struct mtx *m, int what, const char *file, int line);
110 void _thread_lock_flags(struct thread *, int, const char *, int);
112 #define thread_lock(tdp) \
113 _thread_lock_flags((tdp), 0, __FILE__, __LINE__)
114 #define thread_lock_flags(tdp, opt) \
115 _thread_lock_flags((tdp), (opt), __FILE__, __LINE__)
116 #define thread_unlock(tdp) \
117 mtx_unlock_spin((tdp)->td_lock)
119 #define mtx_recurse lock_object.lo_data
121 /* Very simple operations on mtx_lock. */
123 /* Try to obtain mtx_lock once. */
124 #define _mtx_obtain_lock(mp, tid) \
125 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
127 /* Try to release mtx_lock if it is unrecursed and uncontested. */
128 #define _mtx_release_lock(mp, tid) \
129 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
131 /* Release mtx_lock quickly, assuming we own it. */
132 #define _mtx_release_lock_quick(mp) \
133 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
136 * Full lock operations that are suitable to be inlined in non-debug
137 * kernels. If the lock cannot be acquired or released trivially then
138 * the work is deferred to another function.
141 /* Lock a normal mutex. */
142 #define __mtx_lock(mp, tid, opts, file, line) do { \
143 uintptr_t _tid = (uintptr_t)(tid); \
145 if (!_mtx_obtain_lock((mp), _tid)) \
146 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
148 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \
149 mp, 0, 0, (file), (line)); \
153 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
154 * turns out that function calls can be significantly expensive on
155 * some architectures). Since spin locks are not _too_ common,
156 * inlining this code is not too big a deal.
159 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
160 uintptr_t _tid = (uintptr_t)(tid); \
163 if (!_mtx_obtain_lock((mp), _tid)) { \
164 if ((mp)->mtx_lock == _tid) \
165 (mp)->mtx_recurse++; \
167 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
169 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \
170 mp, 0, 0, (file), (line)); \
173 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
174 uintptr_t _tid = (uintptr_t)(tid); \
177 if ((mp)->mtx_lock == _tid) \
178 (mp)->mtx_recurse++; \
180 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
181 (mp)->mtx_lock = _tid; \
186 /* Unlock a normal mutex. */
187 #define __mtx_unlock(mp, tid, opts, file, line) do { \
188 uintptr_t _tid = (uintptr_t)(tid); \
190 if (!_mtx_release_lock((mp), _tid)) \
191 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
195 * Unlock a spin mutex. For spinlocks, we can handle everything
196 * inline, as it's pretty simple and a function call would be too
197 * expensive (at least on some architectures). Since spin locks are
198 * not _too_ common, inlining this code is not too big a deal.
200 * Since we always perform a spinlock_enter() when attempting to acquire a
201 * spin lock, we need to always perform a matching spinlock_exit() when
202 * releasing a spin lock. This includes the recursion cases.
205 #define __mtx_unlock_spin(mp) do { \
206 if (mtx_recursed((mp))) \
207 (mp)->mtx_recurse--; \
209 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
211 _mtx_release_lock_quick((mp)); \
216 #define __mtx_unlock_spin(mp) do { \
217 if (mtx_recursed((mp))) \
218 (mp)->mtx_recurse--; \
220 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \
222 (mp)->mtx_lock = MTX_UNOWNED; \
229 * Exported lock manipulation interface.
231 * mtx_lock(m) locks MTX_DEF mutex `m'
233 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
235 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
237 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
239 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
240 * and passes option flags `opts' to the "hard" function, if required.
241 * With these routines, it is possible to pass flags such as MTX_QUIET
242 * to the appropriate lock manipulation routines.
244 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
245 * it cannot. Rather, it returns 0 on failure and non-zero on success.
246 * It does NOT handle recursion as we assume that if a caller is properly
247 * using this part of the interface, he will know that the lock in question
250 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
251 * relevant option flags `opts.'
253 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
255 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
257 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
259 #define mtx_lock(m) mtx_lock_flags((m), 0)
260 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
261 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
262 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
263 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
267 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
268 void mtx_pool_destroy(struct mtx_pool **poolp);
269 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
270 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
271 #define mtx_pool_lock(pool, ptr) \
272 mtx_lock(mtx_pool_find((pool), (ptr)))
273 #define mtx_pool_lock_spin(pool, ptr) \
274 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
275 #define mtx_pool_unlock(pool, ptr) \
276 mtx_unlock(mtx_pool_find((pool), (ptr)))
277 #define mtx_pool_unlock_spin(pool, ptr) \
278 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
281 * mtxpool_lockbuilder is a pool of sleep locks that is not witness
282 * checked and should only be used for building higher level locks.
284 * mtxpool_sleep is a general purpose pool of sleep mutexes.
286 extern struct mtx_pool *mtxpool_lockbuilder;
287 extern struct mtx_pool *mtxpool_sleep;
290 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
292 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
293 #define mtx_lock_flags(m, opts) \
294 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
295 #define mtx_unlock_flags(m, opts) \
296 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
297 #define mtx_lock_spin_flags(m, opts) \
298 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
299 #define mtx_unlock_spin_flags(m, opts) \
300 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
301 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
302 #define mtx_lock_flags(m, opts) \
303 __mtx_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
304 #define mtx_unlock_flags(m, opts) \
305 __mtx_unlock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
306 #define mtx_lock_spin_flags(m, opts) \
307 __mtx_lock_spin((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
308 #define mtx_unlock_spin_flags(m, opts) \
309 __mtx_unlock_spin((m))
310 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
312 #define mtx_trylock_flags(m, opts) \
313 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
315 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
316 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo))
318 #define mtx_initialized(m) lock_initalized(&(m)->lock_object)
320 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread)
322 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
324 #define mtx_name(m) ((m)->lock_object.lo_name)
329 extern struct mtx Giant;
330 extern struct mtx blocked_lock;
333 * Giant lock manipulation and clean exit macros.
334 * Used to replace return with an exit Giant and return.
336 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
337 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
340 #define DROP_GIANT() \
343 WITNESS_SAVE_DECL(Giant); \
345 if (mtx_owned(&Giant)) { \
346 WITNESS_SAVE(&Giant.lock_object, Giant); \
347 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
348 mtx_unlock(&Giant); \
351 #define PICKUP_GIANT() \
352 PARTIAL_PICKUP_GIANT(); \
355 #define PARTIAL_PICKUP_GIANT() \
356 mtx_assert(&Giant, MA_NOTOWNED); \
357 if (_giantcnt > 0) { \
358 while (_giantcnt--) \
360 WITNESS_RESTORE(&Giant.lock_object, Giant); \
364 #define UGAR(rval) do { \
366 mtx_unlock(&Giant); \
376 #define MTX_SYSINIT(name, mtx, desc, opts) \
377 static struct mtx_args name##_args = { \
382 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
383 mtx_sysinit, &name##_args); \
384 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
388 * The INVARIANTS-enabled mtx_assert() functionality.
390 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
391 * support as _mtx_assert() itself uses them and the latter implies that
392 * _mtx_assert() must build.
394 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
395 #define MA_OWNED LA_XLOCKED
396 #define MA_NOTOWNED LA_UNLOCKED
397 #define MA_RECURSED LA_RECURSED
398 #define MA_NOTRECURSED LA_NOTRECURSED
402 #define mtx_assert(m, what) \
403 _mtx_assert((m), (what), __FILE__, __LINE__)
405 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
407 #else /* INVARIANTS */
408 #define mtx_assert(m, what) (void)0
409 #define GIANT_REQUIRED
410 #endif /* INVARIANTS */
413 * Common lock type names.
415 #define MTX_NETWORK_LOCK "network driver"
418 #endif /* _SYS_MUTEX_H_ */