FreeBSD/Linux Kernel Cross Reference
sys/sys/mutex.h
1 /*-
2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
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
14 * written permission.
15 *
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
26 * SUCH DAMAGE.
27 *
28 * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
29 * $FreeBSD$
30 */
31
32 #ifndef _SYS_MUTEX_H_
33 #define _SYS_MUTEX_H_
34
35 #ifndef LOCORE
36 #include <sys/queue.h>
37 #include <sys/_lock.h>
38 #include <sys/_mutex.h>
39
40 #ifdef _KERNEL
41 #include <sys/pcpu.h>
42 #include <sys/lock_profile.h>
43 #include <machine/atomic.h>
44 #include <machine/cpufunc.h>
45 #endif /* _KERNEL_ */
46 #endif /* !LOCORE */
47
48 #include <machine/mutex.h>
49
50 #ifdef _KERNEL
51
52 /*
53 * Mutex types and options passed to mtx_init(). MTX_QUIET and MTX_DUPOK
54 * can also be passed in.
55 */
56 #define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
57 #define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
58 #define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
59 #define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
60 #define MTX_NOPROFILE 0x00000020 /* Don't profile this lock */
61
62 /*
63 * Option flags passed to certain lock/unlock routines, through the use
64 * of corresponding mtx_{lock,unlock}_flags() interface macros.
65 */
66 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
67 #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */
68
69 /*
70 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
71 * with the exception of MTX_UNOWNED, applies to spin locks.
72 */
73 #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
74 #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
75 #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
76 #define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED)
77
78 /*
79 * Value stored in mutex->mtx_lock to denote a destroyed mutex.
80 */
81 #define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED)
82
83 #endif /* _KERNEL */
84
85 #ifndef LOCORE
86
87 /*
88 * XXX: Friendly reminder to fix things in MP code that is presently being
89 * XXX: worked on.
90 */
91 #define mp_fixme(string)
92
93 #ifdef _KERNEL
94
95 /*
96 * Prototypes
97 *
98 * NOTE: Functions prepended with `_' (underscore) are exported to other parts
99 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
100 * and LOCK_LINE. These functions should not be called directly by any
101 * code using the API. Their macros cover their functionality.
102 *
103 * [See below for descriptions]
104 *
105 */
106 void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
107 void mtx_destroy(struct mtx *m);
108 void mtx_sysinit(void *arg);
109 void mutex_init(void);
110 void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts,
111 const char *file, int line);
112 void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
113 #ifdef SMP
114 void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts,
115 const char *file, int line);
116 #endif
117 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
118 int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
119 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
120 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
121 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
122 int line);
123 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
124 int line);
125 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
126 void _mtx_assert(struct mtx *m, int what, const char *file, int line);
127 #endif
128 void _thread_lock_flags(struct thread *, int, const char *, int);
129
130 #define thread_lock(tdp) \
131 _thread_lock_flags((tdp), 0, __FILE__, __LINE__)
132 #define thread_lock_flags(tdp, opt) \
133 _thread_lock_flags((tdp), (opt), __FILE__, __LINE__)
134 #define thread_unlock(tdp) \
135 mtx_unlock_spin((tdp)->td_lock)
136
137 /*
138 * We define our machine-independent (unoptimized) mutex micro-operations
139 * here, if they are not already defined in the machine-dependent mutex.h
140 */
141
142 /* Try to obtain mtx_lock once. */
143 #ifndef _obtain_lock
144 #define _obtain_lock(mp, tid) \
145 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
146 #endif
147
148 /* Try to release mtx_lock if it is unrecursed and uncontested. */
149 #ifndef _release_lock
150 #define _release_lock(mp, tid) \
151 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
152 #endif
153
154 /* Release mtx_lock quickly, assuming we own it. */
155 #ifndef _release_lock_quick
156 #define _release_lock_quick(mp) \
157 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
158 #endif
159
160 /*
161 * Obtain a sleep lock inline, or call the "hard" function if we can't get it
162 * easy.
163 */
164 #ifndef _get_sleep_lock
165 #define _get_sleep_lock(mp, tid, opts, file, line) do { \
166 uintptr_t _tid = (uintptr_t)(tid); \
167 if (!_obtain_lock((mp), _tid)) { \
168 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
169 } else \
170 lock_profile_obtain_lock_success(&(mp)->lock_object, 0, \
171 0, (file), (line)); \
172 } while (0)
173 #endif
174
175 /*
176 * Obtain a spin lock inline, or call the "hard" function if we can't get it
177 * easy. For spinlocks, we handle recursion inline (it turns out that function
178 * calls can be significantly expensive on some architectures).
179 * Since spin locks are not _too_ common, inlining this code is not too big
180 * a deal.
181 */
182 #ifndef _get_spin_lock
183 #ifdef SMP
184 #define _get_spin_lock(mp, tid, opts, file, line) do { \
185 uintptr_t _tid = (uintptr_t)(tid); \
186 spinlock_enter(); \
187 if (!_obtain_lock((mp), _tid)) { \
188 if ((mp)->mtx_lock == _tid) \
189 (mp)->mtx_recurse++; \
190 else { \
191 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
192 } \
193 } else \
194 lock_profile_obtain_lock_success(&(mp)->lock_object, 0, \
195 0, (file), (line)); \
196 } while (0)
197 #else /* SMP */
198 #define _get_spin_lock(mp, tid, opts, file, line) do { \
199 uintptr_t _tid = (uintptr_t)(tid); \
200 \
201 spinlock_enter(); \
202 if ((mp)->mtx_lock == _tid) \
203 (mp)->mtx_recurse++; \
204 else { \
205 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
206 (mp)->mtx_lock = _tid; \
207 } \
208 } while (0)
209 #endif /* SMP */
210 #endif
211
212 /*
213 * Release a sleep lock inline, or call the "hard" function if we can't do it
214 * easy.
215 */
216 #ifndef _rel_sleep_lock
217 #define _rel_sleep_lock(mp, tid, opts, file, line) do { \
218 uintptr_t _tid = (uintptr_t)(tid); \
219 \
220 if (!_release_lock((mp), _tid)) \
221 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
222 } while (0)
223 #endif
224
225 /*
226 * For spinlocks, we can handle everything inline, as it's pretty simple and
227 * a function call would be too expensive (at least on some architectures).
228 * Since spin locks are not _too_ common, inlining this code is not too big
229 * a deal.
230 *
231 * Since we always perform a spinlock_enter() when attempting to acquire a
232 * spin lock, we need to always perform a matching spinlock_exit() when
233 * releasing a spin lock. This includes the recursion cases.
234 */
235 #ifndef _rel_spin_lock
236 #ifdef SMP
237 #define _rel_spin_lock(mp) do { \
238 if (mtx_recursed((mp))) \
239 (mp)->mtx_recurse--; \
240 else { \
241 lock_profile_release_lock(&(mp)->lock_object); \
242 _release_lock_quick((mp)); \
243 } \
244 spinlock_exit(); \
245 } while (0)
246 #else /* SMP */
247 #define _rel_spin_lock(mp) do { \
248 if (mtx_recursed((mp))) \
249 (mp)->mtx_recurse--; \
250 else \
251 (mp)->mtx_lock = MTX_UNOWNED; \
252 spinlock_exit(); \
253 } while (0)
254 #endif /* SMP */
255 #endif
256
257 /*
258 * Exported lock manipulation interface.
259 *
260 * mtx_lock(m) locks MTX_DEF mutex `m'
261 *
262 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
263 *
264 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
265 *
266 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
267 *
268 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
269 * and passes option flags `opts' to the "hard" function, if required.
270 * With these routines, it is possible to pass flags such as MTX_QUIET
271 * to the appropriate lock manipulation routines.
272 *
273 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
274 * it cannot. Rather, it returns 0 on failure and non-zero on success.
275 * It does NOT handle recursion as we assume that if a caller is properly
276 * using this part of the interface, he will know that the lock in question
277 * is _not_ recursed.
278 *
279 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
280 * relevant option flags `opts.'
281 *
282 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
283 *
284 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
285 *
286 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
287 */
288 #define mtx_lock(m) mtx_lock_flags((m), 0)
289 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
290 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
291 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
292 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
293
294 struct mtx_pool;
295
296 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
297 void mtx_pool_destroy(struct mtx_pool **poolp);
298 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
299 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
300 #define mtx_pool_lock(pool, ptr) \
301 mtx_lock(mtx_pool_find((pool), (ptr)))
302 #define mtx_pool_lock_spin(pool, ptr) \
303 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
304 #define mtx_pool_unlock(pool, ptr) \
305 mtx_unlock(mtx_pool_find((pool), (ptr)))
306 #define mtx_pool_unlock_spin(pool, ptr) \
307 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
308
309 /*
310 * mtxpool_lockbuilder is a pool of sleep locks that is not witness
311 * checked and should only be used for building higher level locks.
312 *
313 * mtxpool_sleep is a general purpose pool of sleep mutexes.
314 */
315 extern struct mtx_pool *mtxpool_lockbuilder;
316 extern struct mtx_pool *mtxpool_sleep;
317
318 #ifndef LOCK_DEBUG
319 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
320 #endif
321 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
322 #define mtx_lock_flags(m, opts) \
323 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
324 #define mtx_unlock_flags(m, opts) \
325 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
326 #define mtx_lock_spin_flags(m, opts) \
327 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
328 #define mtx_unlock_spin_flags(m, opts) \
329 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
330 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
331 #define mtx_lock_flags(m, opts) \
332 _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
333 #define mtx_unlock_flags(m, opts) \
334 _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
335 #define mtx_lock_spin_flags(m, opts) \
336 _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
337 #define mtx_unlock_spin_flags(m, opts) \
338 _rel_spin_lock((m))
339 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
340
341 #define mtx_trylock_flags(m, opts) \
342 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
343
344 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \
345 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo))
346
347 #define mtx_initialized(m) lock_initalized(&(m)->lock_object)
348
349 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread)
350
351 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
352
353 #define mtx_name(m) ((m)->lock_object.lo_name)
354
355 /*
356 * Global locks.
357 */
358 extern struct mtx Giant;
359 extern struct mtx blocked_lock;
360
361 /*
362 * Giant lock manipulation and clean exit macros.
363 * Used to replace return with an exit Giant and return.
364 *
365 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
366 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
367 */
368 #ifndef DROP_GIANT
369 #define DROP_GIANT() \
370 do { \
371 int _giantcnt = 0; \
372 WITNESS_SAVE_DECL(Giant); \
373 \
374 if (mtx_owned(&Giant)) { \
375 WITNESS_SAVE(&Giant.lock_object, Giant); \
376 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
377 mtx_unlock(&Giant); \
378 }
379
380 #define PICKUP_GIANT() \
381 PARTIAL_PICKUP_GIANT(); \
382 } while (0)
383
384 #define PARTIAL_PICKUP_GIANT() \
385 mtx_assert(&Giant, MA_NOTOWNED); \
386 if (_giantcnt > 0) { \
387 while (_giantcnt--) \
388 mtx_lock(&Giant); \
389 WITNESS_RESTORE(&Giant.lock_object, Giant); \
390 }
391 #endif
392
393 #define UGAR(rval) do { \
394 int _val = (rval); \
395 mtx_unlock(&Giant); \
396 return (_val); \
397 } while (0)
398
399 struct mtx_args {
400 struct mtx *ma_mtx;
401 const char *ma_desc;
402 int ma_opts;
403 };
404
405 #define MTX_SYSINIT(name, mtx, desc, opts) \
406 static struct mtx_args name##_args = { \
407 (mtx), \
408 (desc), \
409 (opts) \
410 }; \
411 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
412 mtx_sysinit, &name##_args); \
413 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
414 mtx_destroy, (mtx))
415
416 /*
417 * The INVARIANTS-enabled mtx_assert() functionality.
418 *
419 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
420 * support as _mtx_assert() itself uses them and the latter implies that
421 * _mtx_assert() must build.
422 */
423 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
424 #define MA_OWNED LA_XLOCKED
425 #define MA_NOTOWNED LA_UNLOCKED
426 #define MA_RECURSED LA_RECURSED
427 #define MA_NOTRECURSED LA_NOTRECURSED
428 #endif
429
430 #ifdef INVARIANTS
431 #define mtx_assert(m, what) \
432 _mtx_assert((m), (what), __FILE__, __LINE__)
433
434 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
435
436 #else /* INVARIANTS */
437 #define mtx_assert(m, what)
438 #define GIANT_REQUIRED
439 #endif /* INVARIANTS */
440
441 /*
442 * Common lock type names.
443 */
444 #define MTX_NETWORK_LOCK "network driver"
445
446 #endif /* _KERNEL */
447 #endif /* !LOCORE */
448 #endif /* _SYS_MUTEX_H_ */
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