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 */
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 tid, int opts,
102 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 tid, int opts,
107 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 void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts,
116 const char *file, int line);
117 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
118 void __mtx_assert(const volatile uintptr_t *c, int what, const char *file,
121 void thread_lock_flags_(struct thread *, int, const char *, int);
123 #define thread_lock(tdp) \
124 thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
125 #define thread_lock_flags(tdp, opt) \
126 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
127 #define thread_unlock(tdp) \
128 mtx_unlock_spin((tdp)->td_lock)
131 * Top-level macros to provide lock cookie once the actual mtx is passed.
132 * They will also prevent passing a malformed object to the mtx KPI by
133 * failing compilation as the mtx_lock reserved member will not be found.
135 #define mtx_init(m, n, t, o) \
136 _mtx_init(&(m)->mtx_lock, n, t, o)
137 #define mtx_destroy(m) \
138 _mtx_destroy(&(m)->mtx_lock)
139 #define mtx_trylock_flags_(m, o, f, l) \
140 _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l)
141 #define _mtx_lock_sleep(m, t, o, f, l) \
142 __mtx_lock_sleep(&(m)->mtx_lock, t, o, f, l)
143 #define _mtx_unlock_sleep(m, o, f, l) \
144 __mtx_unlock_sleep(&(m)->mtx_lock, o, f, l)
146 #define _mtx_lock_spin(m, t, o, f, l) \
147 _mtx_lock_spin_cookie(&(m)->mtx_lock, t, o, f, l)
149 #define _mtx_lock_flags(m, o, f, l) \
150 __mtx_lock_flags(&(m)->mtx_lock, o, f, l)
151 #define _mtx_unlock_flags(m, o, f, l) \
152 __mtx_unlock_flags(&(m)->mtx_lock, o, f, l)
153 #define _mtx_lock_spin_flags(m, o, f, l) \
154 __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l)
155 #define _mtx_unlock_spin_flags(m, o, f, l) \
156 __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l)
157 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
158 #define _mtx_assert(m, w, f, l) \
159 __mtx_assert(&(m)->mtx_lock, w, f, l)
162 #define mtx_recurse lock_object.lo_data
164 /* Very simple operations on mtx_lock. */
166 /* Try to obtain mtx_lock once. */
167 #define _mtx_obtain_lock(mp, tid) \
168 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
170 /* Try to release mtx_lock if it is unrecursed and uncontested. */
171 #define _mtx_release_lock(mp, tid) \
172 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
174 /* Release mtx_lock quickly, assuming we own it. */
175 #define _mtx_release_lock_quick(mp) \
176 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
179 * Full lock operations that are suitable to be inlined in non-debug
180 * kernels. If the lock cannot be acquired or released trivially then
181 * the work is deferred to another function.
184 /* Lock a normal mutex. */
185 #define __mtx_lock(mp, tid, opts, file, line) do { \
186 uintptr_t _tid = (uintptr_t)(tid); \
188 if (!_mtx_obtain_lock((mp), _tid)) \
189 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
191 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, \
192 mp, 0, 0, file, line); \
196 * Lock a spin mutex. For spinlocks, we handle recursion inline (it
197 * turns out that function calls can be significantly expensive on
198 * some architectures). Since spin locks are not _too_ common,
199 * inlining this code is not too big a deal.
202 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
203 uintptr_t _tid = (uintptr_t)(tid); \
206 if (!_mtx_obtain_lock((mp), _tid)) { \
207 if ((mp)->mtx_lock == _tid) \
208 (mp)->mtx_recurse++; \
210 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
212 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, \
213 mp, 0, 0, file, line); \
216 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \
217 uintptr_t _tid = (uintptr_t)(tid); \
220 if ((mp)->mtx_lock == _tid) \
221 (mp)->mtx_recurse++; \
223 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
224 (mp)->mtx_lock = _tid; \
229 /* Unlock a normal mutex. */
230 #define __mtx_unlock(mp, tid, opts, file, line) do { \
231 uintptr_t _tid = (uintptr_t)(tid); \
233 if ((mp)->mtx_recurse == 0) \
234 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, mp); \
235 if (!_mtx_release_lock((mp), _tid)) \
236 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
240 * Unlock a spin mutex. For spinlocks, we can handle everything
241 * inline, as it's pretty simple and a function call would be too
242 * expensive (at least on some architectures). Since spin locks are
243 * not _too_ common, inlining this code is not too big a deal.
245 * Since we always perform a spinlock_enter() when attempting to acquire a
246 * spin lock, we need to always perform a matching spinlock_exit() when
247 * releasing a spin lock. This includes the recursion cases.
250 #define __mtx_unlock_spin(mp) do { \
251 if (mtx_recursed((mp))) \
252 (mp)->mtx_recurse--; \
254 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp); \
255 _mtx_release_lock_quick((mp)); \
260 #define __mtx_unlock_spin(mp) do { \
261 if (mtx_recursed((mp))) \
262 (mp)->mtx_recurse--; \
264 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp); \
265 (mp)->mtx_lock = MTX_UNOWNED; \
272 * Exported lock manipulation interface.
274 * mtx_lock(m) locks MTX_DEF mutex `m'
276 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
278 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
280 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
282 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
283 * and passes option flags `opts' to the "hard" function, if required.
284 * With these routines, it is possible to pass flags such as MTX_QUIET
285 * to the appropriate lock manipulation routines.
287 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
288 * it cannot. Rather, it returns 0 on failure and non-zero on success.
289 * It does NOT handle recursion as we assume that if a caller is properly
290 * using this part of the interface, he will know that the lock in question
293 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
294 * relevant option flags `opts.'
296 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
298 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
300 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
302 #define mtx_lock(m) mtx_lock_flags((m), 0)
303 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
304 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
305 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
306 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
310 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
311 void mtx_pool_destroy(struct mtx_pool **poolp);
312 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
313 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
314 #define mtx_pool_lock(pool, ptr) \
315 mtx_lock(mtx_pool_find((pool), (ptr)))
316 #define mtx_pool_lock_spin(pool, ptr) \
317 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
318 #define mtx_pool_unlock(pool, ptr) \
319 mtx_unlock(mtx_pool_find((pool), (ptr)))
320 #define mtx_pool_unlock_spin(pool, ptr) \
321 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
324 * mtxpool_sleep is a general purpose pool of sleep mutexes.
326 extern struct mtx_pool *mtxpool_sleep;
329 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
331 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
332 #define mtx_lock_flags_(m, opts, file, line) \
333 _mtx_lock_flags((m), (opts), (file), (line))
334 #define mtx_unlock_flags_(m, opts, file, line) \
335 _mtx_unlock_flags((m), (opts), (file), (line))
336 #define mtx_lock_spin_flags_(m, opts, file, line) \
337 _mtx_lock_spin_flags((m), (opts), (file), (line))
338 #define mtx_unlock_spin_flags_(m, opts, file, line) \
339 _mtx_unlock_spin_flags((m), (opts), (file), (line))
340 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
341 #define mtx_lock_flags_(m, opts, file, line) \
342 __mtx_lock((m), curthread, (opts), (file), (line))
343 #define mtx_unlock_flags_(m, opts, file, line) \
344 __mtx_unlock((m), curthread, (opts), (file), (line))
345 #define mtx_lock_spin_flags_(m, opts, file, line) \
346 __mtx_lock_spin((m), curthread, (opts), (file), (line))
347 #define mtx_unlock_spin_flags_(m, opts, file, line) \
348 __mtx_unlock_spin((m))
349 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
352 #define mtx_assert_(m, what, file, line) \
353 _mtx_assert((m), (what), (file), (line))
355 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
357 #else /* INVARIANTS */
358 #define mtx_assert_(m, what, file, line) (void)0
359 #define GIANT_REQUIRED
360 #endif /* INVARIANTS */
362 #define mtx_lock_flags(m, opts) \
363 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
364 #define mtx_unlock_flags(m, opts) \
365 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
366 #define mtx_lock_spin_flags(m, opts) \
367 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
368 #define mtx_unlock_spin_flags(m, opts) \
369 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
370 #define mtx_trylock_flags(m, opts) \
371 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
372 #define mtx_assert(m, what) \
373 mtx_assert_((m), (what), __FILE__, __LINE__)
375 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
376 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), \
377 tick_sbt * (timo), 0, C_HARDCLOCK)
379 #define mtx_initialized(m) lock_initialized(&(m)->lock_object)
381 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread)
383 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
385 #define mtx_name(m) ((m)->lock_object.lo_name)
390 extern struct mtx Giant;
391 extern struct mtx blocked_lock;
394 * Giant lock manipulation and clean exit macros.
395 * Used to replace return with an exit Giant and return.
397 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
398 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
401 #define DROP_GIANT() \
404 WITNESS_SAVE_DECL(Giant); \
406 if (mtx_owned(&Giant)) { \
407 WITNESS_SAVE(&Giant.lock_object, Giant); \
408 for (_giantcnt = 0; mtx_owned(&Giant) && \
409 !SCHEDULER_STOPPED(); _giantcnt++) \
410 mtx_unlock(&Giant); \
413 #define PICKUP_GIANT() \
414 PARTIAL_PICKUP_GIANT(); \
417 #define PARTIAL_PICKUP_GIANT() \
418 mtx_assert(&Giant, MA_NOTOWNED); \
419 if (_giantcnt > 0) { \
420 while (_giantcnt--) \
422 WITNESS_RESTORE(&Giant.lock_object, Giant); \
432 #define MTX_SYSINIT(name, mtx, desc, opts) \
433 static struct mtx_args name##_args = { \
438 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
439 mtx_sysinit, &name##_args); \
440 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
441 _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
444 * The INVARIANTS-enabled mtx_assert() functionality.
446 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
447 * support as _mtx_assert() itself uses them and the latter implies that
448 * _mtx_assert() must build.
450 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
451 #define MA_OWNED LA_XLOCKED
452 #define MA_NOTOWNED LA_UNLOCKED
453 #define MA_RECURSED LA_RECURSED
454 #define MA_NOTRECURSED LA_NOTRECURSED
458 * Common lock type names.
460 #define MTX_NETWORK_LOCK "network driver"
463 #endif /* _SYS_MUTEX_H_ */