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: src/sys/sys/mutex.h,v 1.73.2.3 2005/03/28 20:17:30 jhb Exp $
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 <machine/atomic.h>
43 #include <machine/cpufunc.h>
44 #endif /* _KERNEL_ */
45 #endif /* !LOCORE */
46
47 #include <machine/mutex.h>
48
49 #ifdef _KERNEL
50
51 /*
52 * Mutex types and options passed to mtx_init(). MTX_QUIET can also be
53 * passed in.
54 */
55 #define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
56 #define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
57 #define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
58 #define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
59 #define MTX_DUPOK 0x00000020 /* Don't log a duplicate acquire */
60
61 /*
62 * Option flags passed to certain lock/unlock routines, through the use
63 * of corresponding mtx_{lock,unlock}_flags() interface macros.
64 */
65 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
66
67 /*
68 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
69 * with the exception of MTX_UNOWNED, applies to spin locks.
70 */
71 #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
72 #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
73 #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
74 #define MTX_FLAGMASK ~(MTX_RECURSED | MTX_CONTESTED)
75
76 #endif /* _KERNEL */
77
78 #ifndef LOCORE
79
80 /*
81 * XXX: Friendly reminder to fix things in MP code that is presently being
82 * XXX: worked on.
83 */
84 #define mp_fixme(string)
85
86 #ifdef _KERNEL
87
88 /*
89 * Prototypes
90 *
91 * NOTE: Functions prepended with `_' (underscore) are exported to other parts
92 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
93 * and LOCK_LINE. These functions should not be called directly by any
94 * code using the API. Their macros cover their functionality.
95 *
96 * [See below for descriptions]
97 *
98 */
99 void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
100 void mtx_destroy(struct mtx *m);
101 void mtx_sysinit(void *arg);
102 void mutex_init(void);
103 void _mtx_lock_sleep(struct mtx *m, struct thread *td, int opts,
104 const char *file, int line);
105 void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
106 #ifdef SMP
107 void _mtx_lock_spin(struct mtx *m, struct thread *td, int opts,
108 const char *file, int line);
109 #endif
110 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
111 int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
112 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
113 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
114 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
115 int line);
116 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
117 int line);
118 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
119 void _mtx_assert(struct mtx *m, int what, const char *file, int line);
120 #endif
121
122 /*
123 * We define our machine-independent (unoptimized) mutex micro-operations
124 * here, if they are not already defined in the machine-dependent mutex.h
125 */
126
127 /* Actually obtain mtx_lock */
128 #ifndef _obtain_lock
129 #define _obtain_lock(mp, tid) \
130 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid))
131 #endif
132
133 /* Actually release mtx_lock */
134 #ifndef _release_lock
135 #define _release_lock(mp, tid) \
136 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED)
137 #endif
138
139 /* Actually release mtx_lock quickly, assuming we own it. */
140 #ifndef _release_lock_quick
141 #define _release_lock_quick(mp) \
142 atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED)
143 #endif
144
145 /*
146 * Obtain a sleep lock inline, or call the "hard" function if we can't get it
147 * easy.
148 */
149 #ifndef _get_sleep_lock
150 #define _get_sleep_lock(mp, tid, opts, file, line) do { \
151 struct thread *_tid = (tid); \
152 \
153 if (!_obtain_lock((mp), _tid)) \
154 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
155 } while (0)
156 #endif
157
158 /*
159 * Obtain a spin lock inline, or call the "hard" function if we can't get it
160 * easy. For spinlocks, we handle recursion inline (it turns out that function
161 * calls can be significantly expensive on some architectures).
162 * Since spin locks are not _too_ common, inlining this code is not too big
163 * a deal.
164 */
165 #ifndef _get_spin_lock
166 #ifdef SMP
167 #define _get_spin_lock(mp, tid, opts, file, line) do { \
168 struct thread *_tid = (tid); \
169 \
170 critical_enter(); \
171 if (!_obtain_lock((mp), _tid)) { \
172 if ((mp)->mtx_lock == (uintptr_t)_tid) \
173 (mp)->mtx_recurse++; \
174 else \
175 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
176 } \
177 } while (0)
178 #else /* SMP */
179 #define _get_spin_lock(mp, tid, opts, file, line) do { \
180 struct thread *_tid = (tid); \
181 \
182 critical_enter(); \
183 if ((mp)->mtx_lock == (uintptr_t)_tid) \
184 (mp)->mtx_recurse++; \
185 else { \
186 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
187 (mp)->mtx_lock = (uintptr_t)_tid; \
188 } \
189 } while (0)
190 #endif /* SMP */
191 #endif
192
193 /*
194 * Release a sleep lock inline, or call the "hard" function if we can't do it
195 * easy.
196 */
197 #ifndef _rel_sleep_lock
198 #define _rel_sleep_lock(mp, tid, opts, file, line) do { \
199 if (!_release_lock((mp), (tid))) \
200 _mtx_unlock_sleep((mp), (opts), (file), (line)); \
201 } while (0)
202 #endif
203
204 /*
205 * For spinlocks, we can handle everything inline, as it's pretty simple and
206 * a function call would be too expensive (at least on some architectures).
207 * Since spin locks are not _too_ common, inlining this code is not too big
208 * a deal.
209 *
210 * Since we always perform a critical_enter() when attempting to acquire a
211 * spin lock, we need to always perform a matching critical_exit() when
212 * releasing a spin lock. This includes the recursion cases.
213 */
214 #ifndef _rel_spin_lock
215 #ifdef SMP
216 #define _rel_spin_lock(mp) do { \
217 if (mtx_recursed((mp))) \
218 (mp)->mtx_recurse--; \
219 else \
220 _release_lock_quick((mp)); \
221 critical_exit(); \
222 } while (0)
223 #else /* SMP */
224 #define _rel_spin_lock(mp) do { \
225 if (mtx_recursed((mp))) \
226 (mp)->mtx_recurse--; \
227 else \
228 (mp)->mtx_lock = MTX_UNOWNED; \
229 critical_exit(); \
230 } while (0)
231 #endif /* SMP */
232 #endif
233
234 /*
235 * Exported lock manipulation interface.
236 *
237 * mtx_lock(m) locks MTX_DEF mutex `m'
238 *
239 * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
240 *
241 * mtx_unlock(m) unlocks MTX_DEF mutex `m'
242 *
243 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
244 *
245 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
246 * and passes option flags `opts' to the "hard" function, if required.
247 * With these routines, it is possible to pass flags such as MTX_QUIET
248 * to the appropriate lock manipulation routines.
249 *
250 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
251 * it cannot. Rather, it returns 0 on failure and non-zero on success.
252 * It does NOT handle recursion as we assume that if a caller is properly
253 * using this part of the interface, he will know that the lock in question
254 * is _not_ recursed.
255 *
256 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
257 * relevant option flags `opts.'
258 *
259 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
260 *
261 * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
262 *
263 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
264 */
265 #define mtx_lock(m) mtx_lock_flags((m), 0)
266 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
267 #define mtx_trylock(m) mtx_trylock_flags((m), 0)
268 #define mtx_unlock(m) mtx_unlock_flags((m), 0)
269 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
270
271 struct mtx_pool;
272
273 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
274 void mtx_pool_destroy(struct mtx_pool **poolp);
275 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
276 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
277 #define mtx_pool_lock(pool, ptr) \
278 mtx_lock(mtx_pool_find((pool), (ptr)))
279 #define mtx_pool_lock_spin(pool, ptr) \
280 mtx_lock_spin(mtx_pool_find((pool), (ptr)))
281 #define mtx_pool_unlock(pool, ptr) \
282 mtx_unlock(mtx_pool_find((pool), (ptr)))
283 #define mtx_pool_unlock_spin(pool, ptr) \
284 mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
285
286 /*
287 * mtxpool_lockbuilder is a pool of sleep locks that is not witness
288 * checked and should only be used for building higher level locks.
289 *
290 * mtxpool_sleep is a general purpose pool of sleep mutexes.
291 */
292 extern struct mtx_pool *mtxpool_lockbuilder;
293 extern struct mtx_pool *mtxpool_sleep;
294
295 #ifndef LOCK_DEBUG
296 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
297 #endif
298 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
299 #define mtx_lock_flags(m, opts) \
300 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
301 #define mtx_unlock_flags(m, opts) \
302 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
303 #define mtx_lock_spin_flags(m, opts) \
304 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
305 #define mtx_unlock_spin_flags(m, opts) \
306 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
307 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
308 #define mtx_lock_flags(m, opts) \
309 _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
310 #define mtx_unlock_flags(m, opts) \
311 _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
312 #define mtx_lock_spin_flags(m, opts) \
313 _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
314 #define mtx_unlock_spin_flags(m, opts) \
315 _rel_spin_lock((m))
316 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
317
318 #define mtx_trylock_flags(m, opts) \
319 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
320
321 #define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED)
322
323 #define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread)
324
325 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
326
327 #define mtx_name(m) ((m)->mtx_object.lo_name)
328
329 /*
330 * Global locks.
331 */
332 extern struct mtx sched_lock;
333 extern struct mtx Giant;
334
335 /*
336 * Giant lock manipulation and clean exit macros.
337 * Used to replace return with an exit Giant and return.
338 *
339 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
340 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
341 */
342 #ifndef DROP_GIANT
343 #define DROP_GIANT() \
344 do { \
345 int _giantcnt; \
346 WITNESS_SAVE_DECL(Giant); \
347 \
348 if (mtx_owned(&Giant)) \
349 WITNESS_SAVE(&Giant.mtx_object, Giant); \
350 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
351 mtx_unlock(&Giant)
352
353 #define PICKUP_GIANT() \
354 mtx_assert(&Giant, MA_NOTOWNED); \
355 while (_giantcnt--) \
356 mtx_lock(&Giant); \
357 if (mtx_owned(&Giant)) \
358 WITNESS_RESTORE(&Giant.mtx_object, Giant); \
359 } while (0)
360
361 #define PARTIAL_PICKUP_GIANT() \
362 mtx_assert(&Giant, MA_NOTOWNED); \
363 while (_giantcnt--) \
364 mtx_lock(&Giant); \
365 if (mtx_owned(&Giant)) \
366 WITNESS_RESTORE(&Giant.mtx_object, Giant)
367 #endif
368
369 /*
370 * Network MPSAFE temporary workarounds. When debug_mpsafenet
371 * is 1 the network is assumed to operate without Giant on the
372 * input path and protocols that require Giant must collect it
373 * on entry. When 0 Giant is grabbed in the network interface
374 * ISR's and in the netisr path and there is no need to grab
375 * the Giant lock. Note that, unlike GIANT_PICKUP() and
376 * GIANT_DROP(), these macros directly wrap mutex operations
377 * without special recursion handling.
378 *
379 * This mechanism is intended as temporary until everything of
380 * importance is properly locked. Note: the semantics for
381 * NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT()
382 * and PICKUP_GIANT(), as they are plain mutex operations
383 * without a recursion counter.
384 */
385 extern int debug_mpsafenet; /* defined in net/netisr.c */
386 #define NET_LOCK_GIANT() do { \
387 if (!debug_mpsafenet) \
388 mtx_lock(&Giant); \
389 } while (0)
390 #define NET_UNLOCK_GIANT() do { \
391 if (!debug_mpsafenet) \
392 mtx_unlock(&Giant); \
393 } while (0)
394 #define NET_ASSERT_GIANT() do { \
395 if (!debug_mpsafenet) \
396 mtx_assert(&Giant, MA_OWNED); \
397 } while (0)
398 #define NET_CALLOUT_MPSAFE (debug_mpsafenet ? CALLOUT_MPSAFE : 0)
399
400 #define UGAR(rval) do { \
401 int _val = (rval); \
402 mtx_unlock(&Giant); \
403 return (_val); \
404 } while (0)
405
406 struct mtx_args {
407 struct mtx *ma_mtx;
408 const char *ma_desc;
409 int ma_opts;
410 };
411
412 #define MTX_SYSINIT(name, mtx, desc, opts) \
413 static struct mtx_args name##_args = { \
414 (mtx), \
415 (desc), \
416 (opts) \
417 }; \
418 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
419 mtx_sysinit, &name##_args)
420
421 /*
422 * The INVARIANTS-enabled mtx_assert() functionality.
423 *
424 * The constants need to be defined for INVARIANT_SUPPORT infrastructure
425 * support as _mtx_assert() itself uses them and the latter implies that
426 * _mtx_assert() must build.
427 */
428 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
429 #define MA_OWNED 0x01
430 #define MA_NOTOWNED 0x02
431 #define MA_RECURSED 0x04
432 #define MA_NOTRECURSED 0x08
433 #endif
434
435 #ifdef INVARIANTS
436 #define mtx_assert(m, what) \
437 _mtx_assert((m), (what), __FILE__, __LINE__)
438
439 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
440
441 #else /* INVARIANTS */
442 #define mtx_assert(m, what)
443 #define GIANT_REQUIRED
444 #endif /* INVARIANTS */
445
446 /*
447 * Common lock type names.
448 */
449 #define MTX_NETWORK_LOCK "network driver"
450
451 #endif /* _KERNEL */
452 #endif /* !LOCORE */
453 #endif /* _SYS_MUTEX_H_ */
Cache object: 2925dfca6df3b1734c48a495801fdf40
|