Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/sys/mutex.h
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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: releng/6.1/sys/sys/mutex.h 158179 2006-04-30 16:44:43Z cvs2svn $ 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 and MTX_DUPOK 53 * can also be 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 60 /* 61 * Option flags passed to certain lock/unlock routines, through the use 62 * of corresponding mtx_{lock,unlock}_flags() interface macros. 63 */ 64 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */ 65 #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */ 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, uintptr_t tid, 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, uintptr_t tid, 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 /* Try to obtain mtx_lock once. */ 128 #ifndef _obtain_lock 129 #define _obtain_lock(mp, tid) \ 130 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid)) 131 #endif 132 133 /* Try to release mtx_lock if it is unrecursed and uncontested. */ 134 #ifndef _release_lock 135 #define _release_lock(mp, tid) \ 136 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED) 137 #endif 138 139 /* 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, 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 uintptr_t _tid = (uintptr_t)(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 uintptr_t _tid = (uintptr_t)(tid); \ 169 \ 170 spinlock_enter(); \ 171 if (!_obtain_lock((mp), _tid)) { \ 172 if ((mp)->mtx_lock == _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 uintptr_t _tid = (uintptr_t)(tid); \ 181 \ 182 spinlock_enter(); \ 183 if ((mp)->mtx_lock == _tid) \ 184 (mp)->mtx_recurse++; \ 185 else { \ 186 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \ 187 (mp)->mtx_lock = _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 uintptr_t _tid = (uintptr_t)(tid); \ 200 \ 201 if (!_release_lock((mp), _tid)) \ 202 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 203 } while (0) 204 #endif 205 206 /* 207 * For spinlocks, we can handle everything inline, as it's pretty simple and 208 * a function call would be too expensive (at least on some architectures). 209 * Since spin locks are not _too_ common, inlining this code is not too big 210 * a deal. 211 * 212 * Since we always perform a spinlock_enter() when attempting to acquire a 213 * spin lock, we need to always perform a matching spinlock_exit() when 214 * releasing a spin lock. This includes the recursion cases. 215 */ 216 #ifndef _rel_spin_lock 217 #ifdef SMP 218 #define _rel_spin_lock(mp) do { \ 219 if (mtx_recursed((mp))) \ 220 (mp)->mtx_recurse--; \ 221 else \ 222 _release_lock_quick((mp)); \ 223 spinlock_exit(); \ 224 } while (0) 225 #else /* SMP */ 226 #define _rel_spin_lock(mp) do { \ 227 if (mtx_recursed((mp))) \ 228 (mp)->mtx_recurse--; \ 229 else \ 230 (mp)->mtx_lock = MTX_UNOWNED; \ 231 spinlock_exit(); \ 232 } while (0) 233 #endif /* SMP */ 234 #endif 235 236 /* 237 * Exported lock manipulation interface. 238 * 239 * mtx_lock(m) locks MTX_DEF mutex `m' 240 * 241 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 242 * 243 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 244 * 245 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 246 * 247 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 248 * and passes option flags `opts' to the "hard" function, if required. 249 * With these routines, it is possible to pass flags such as MTX_QUIET 250 * to the appropriate lock manipulation routines. 251 * 252 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 253 * it cannot. Rather, it returns 0 on failure and non-zero on success. 254 * It does NOT handle recursion as we assume that if a caller is properly 255 * using this part of the interface, he will know that the lock in question 256 * is _not_ recursed. 257 * 258 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 259 * relevant option flags `opts.' 260 * 261 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. 262 * 263 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 264 * 265 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 266 */ 267 #define mtx_lock(m) mtx_lock_flags((m), 0) 268 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 269 #define mtx_trylock(m) mtx_trylock_flags((m), 0) 270 #define mtx_unlock(m) mtx_unlock_flags((m), 0) 271 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 272 273 struct mtx_pool; 274 275 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); 276 void mtx_pool_destroy(struct mtx_pool **poolp); 277 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); 278 struct mtx *mtx_pool_alloc(struct mtx_pool *pool); 279 #define mtx_pool_lock(pool, ptr) \ 280 mtx_lock(mtx_pool_find((pool), (ptr))) 281 #define mtx_pool_lock_spin(pool, ptr) \ 282 mtx_lock_spin(mtx_pool_find((pool), (ptr))) 283 #define mtx_pool_unlock(pool, ptr) \ 284 mtx_unlock(mtx_pool_find((pool), (ptr))) 285 #define mtx_pool_unlock_spin(pool, ptr) \ 286 mtx_unlock_spin(mtx_pool_find((pool), (ptr))) 287 288 /* 289 * mtxpool_lockbuilder is a pool of sleep locks that is not witness 290 * checked and should only be used for building higher level locks. 291 * 292 * mtxpool_sleep is a general purpose pool of sleep mutexes. 293 */ 294 extern struct mtx_pool *mtxpool_lockbuilder; 295 extern struct mtx_pool *mtxpool_sleep; 296 297 #ifndef LOCK_DEBUG 298 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h> 299 #endif 300 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) 301 #define mtx_lock_flags(m, opts) \ 302 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 303 #define mtx_unlock_flags(m, opts) \ 304 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 305 #define mtx_lock_spin_flags(m, opts) \ 306 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 307 #define mtx_unlock_spin_flags(m, opts) \ 308 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 309 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ 310 #define mtx_lock_flags(m, opts) \ 311 _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 312 #define mtx_unlock_flags(m, opts) \ 313 _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 314 #define mtx_lock_spin_flags(m, opts) \ 315 _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 316 #define mtx_unlock_spin_flags(m, opts) \ 317 _rel_spin_lock((m)) 318 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ 319 320 #define mtx_trylock_flags(m, opts) \ 321 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE) 322 323 #define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED) 324 325 #define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread) 326 327 #define mtx_recursed(m) ((m)->mtx_recurse != 0) 328 329 #define mtx_name(m) ((m)->mtx_object.lo_name) 330 331 /* 332 * Global locks. 333 */ 334 extern struct mtx sched_lock; 335 extern struct mtx Giant; 336 337 /* 338 * Giant lock manipulation and clean exit macros. 339 * Used to replace return with an exit Giant and return. 340 * 341 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 342 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. 343 */ 344 #ifndef DROP_GIANT 345 #define DROP_GIANT() \ 346 do { \ 347 int _giantcnt; \ 348 WITNESS_SAVE_DECL(Giant); \ 349 \ 350 if (mtx_owned(&Giant)) \ 351 WITNESS_SAVE(&Giant.mtx_object, Giant); \ 352 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 353 mtx_unlock(&Giant) 354 355 #define PICKUP_GIANT() \ 356 mtx_assert(&Giant, MA_NOTOWNED); \ 357 while (_giantcnt--) \ 358 mtx_lock(&Giant); \ 359 if (mtx_owned(&Giant)) \ 360 WITNESS_RESTORE(&Giant.mtx_object, Giant); \ 361 } while (0) 362 363 #define PARTIAL_PICKUP_GIANT() \ 364 mtx_assert(&Giant, MA_NOTOWNED); \ 365 while (_giantcnt--) \ 366 mtx_lock(&Giant); \ 367 if (mtx_owned(&Giant)) \ 368 WITNESS_RESTORE(&Giant.mtx_object, Giant) 369 #endif 370 371 /* 372 * Network MPSAFE temporary workarounds. When debug_mpsafenet 373 * is 1 the network is assumed to operate without Giant on the 374 * input path and protocols that require Giant must collect it 375 * on entry. When 0 Giant is grabbed in the network interface 376 * ISR's and in the netisr path and there is no need to grab 377 * the Giant lock. Note that, unlike GIANT_PICKUP() and 378 * GIANT_DROP(), these macros directly wrap mutex operations 379 * without special recursion handling. 380 * 381 * This mechanism is intended as temporary until everything of 382 * importance is properly locked. Note: the semantics for 383 * NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT() 384 * and PICKUP_GIANT(), as they are plain mutex operations 385 * without a recursion counter. 386 */ 387 extern int debug_mpsafenet; /* defined in net/netisr.c */ 388 #define NET_LOCK_GIANT() do { \ 389 if (!debug_mpsafenet) \ 390 mtx_lock(&Giant); \ 391 } while (0) 392 #define NET_UNLOCK_GIANT() do { \ 393 if (!debug_mpsafenet) \ 394 mtx_unlock(&Giant); \ 395 } while (0) 396 #define NET_ASSERT_GIANT() do { \ 397 if (!debug_mpsafenet) \ 398 mtx_assert(&Giant, MA_OWNED); \ 399 } while (0) 400 #define NET_CALLOUT_MPSAFE (debug_mpsafenet ? CALLOUT_MPSAFE : 0) 401 402 #define UGAR(rval) do { \ 403 int _val = (rval); \ 404 mtx_unlock(&Giant); \ 405 return (_val); \ 406 } while (0) 407 408 struct mtx_args { 409 struct mtx *ma_mtx; 410 const char *ma_desc; 411 int ma_opts; 412 }; 413 414 #define MTX_SYSINIT(name, mtx, desc, opts) \ 415 static struct mtx_args name##_args = { \ 416 (mtx), \ 417 (desc), \ 418 (opts) \ 419 }; \ 420 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 421 mtx_sysinit, &name##_args); \ 422 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 423 mtx_destroy, (mtx)) 424 425 /* 426 * The INVARIANTS-enabled mtx_assert() functionality. 427 * 428 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 429 * support as _mtx_assert() itself uses them and the latter implies that 430 * _mtx_assert() must build. 431 */ 432 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 433 #define MA_OWNED 0x01 434 #define MA_NOTOWNED 0x02 435 #define MA_RECURSED 0x04 436 #define MA_NOTRECURSED 0x08 437 #endif 438 439 #ifdef INVARIANTS 440 #define mtx_assert(m, what) \ 441 _mtx_assert((m), (what), __FILE__, __LINE__) 442 443 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED) 444 445 #else /* INVARIANTS */ 446 #define mtx_assert(m, what) 447 #define GIANT_REQUIRED 448 #endif /* INVARIANTS */ 449 450 /* 451 * Common lock type names. 452 */ 453 #define MTX_NETWORK_LOCK "network driver" 454 455 #endif /* _KERNEL */ 456 #endif /* !LOCORE */ 457 #endif /* _SYS_MUTEX_H_ */
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