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/5.3/sys/sys/mutex.h 136588 2004-10-16 08:43:07Z 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 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 void _mtx_lock_spin(struct mtx *m, struct thread *td, int opts, 107 const char *file, int line); 108 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line); 109 int _mtx_trylock(struct mtx *m, int opts, const char *file, int line); 110 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line); 111 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line); 112 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, 113 int line); 114 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, 115 int line); 116 #ifdef INVARIANT_SUPPORT 117 void _mtx_assert(struct mtx *m, int what, const char *file, int line); 118 #endif 119 120 /* 121 * We define our machine-independent (unoptimized) mutex micro-operations 122 * here, if they are not already defined in the machine-dependent mutex.h 123 */ 124 125 /* Actually obtain mtx_lock */ 126 #ifndef _obtain_lock 127 #define _obtain_lock(mp, tid) \ 128 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid)) 129 #endif 130 131 /* Actually release mtx_lock */ 132 #ifndef _release_lock 133 #define _release_lock(mp, tid) \ 134 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED) 135 #endif 136 137 /* Actually release mtx_lock quickly, assuming we own it. */ 138 #ifndef _release_lock_quick 139 #define _release_lock_quick(mp) \ 140 atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED) 141 #endif 142 143 /* 144 * Obtain a sleep lock inline, or call the "hard" function if we can't get it 145 * easy. 146 */ 147 #ifndef _get_sleep_lock 148 #define _get_sleep_lock(mp, tid, opts, file, line) do { \ 149 struct thread *_tid = (tid); \ 150 \ 151 if (!_obtain_lock((mp), _tid)) \ 152 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \ 153 } while (0) 154 #endif 155 156 /* 157 * Obtain a spin lock inline, or call the "hard" function if we can't get it 158 * easy. For spinlocks, we handle recursion inline (it turns out that function 159 * calls can be significantly expensive on some architectures). 160 * Since spin locks are not _too_ common, inlining this code is not too big 161 * a deal. 162 */ 163 #ifndef _get_spin_lock 164 #define _get_spin_lock(mp, tid, opts, file, line) do { \ 165 struct thread *_tid = (tid); \ 166 \ 167 critical_enter(); \ 168 if (!_obtain_lock((mp), _tid)) { \ 169 if ((mp)->mtx_lock == (uintptr_t)_tid) \ 170 (mp)->mtx_recurse++; \ 171 else \ 172 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \ 173 } \ 174 } while (0) 175 #endif 176 177 /* 178 * Release a sleep lock inline, or call the "hard" function if we can't do it 179 * easy. 180 */ 181 #ifndef _rel_sleep_lock 182 #define _rel_sleep_lock(mp, tid, opts, file, line) do { \ 183 if (!_release_lock((mp), (tid))) \ 184 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 185 } while (0) 186 #endif 187 188 /* 189 * For spinlocks, we can handle everything inline, as it's pretty simple and 190 * a function call would be too expensive (at least on some architectures). 191 * Since spin locks are not _too_ common, inlining this code is not too big 192 * a deal. 193 * 194 * Since we always perform a critical_enter() when attempting to acquire a 195 * spin lock, we need to always perform a matching critical_exit() when 196 * releasing a spin lock. This includes the recursion cases. 197 */ 198 #ifndef _rel_spin_lock 199 #define _rel_spin_lock(mp) do { \ 200 if (mtx_recursed((mp))) \ 201 (mp)->mtx_recurse--; \ 202 else \ 203 _release_lock_quick((mp)); \ 204 critical_exit(); \ 205 } while (0) 206 #endif 207 208 /* 209 * Exported lock manipulation interface. 210 * 211 * mtx_lock(m) locks MTX_DEF mutex `m' 212 * 213 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 214 * 215 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 216 * 217 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 218 * 219 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 220 * and passes option flags `opts' to the "hard" function, if required. 221 * With these routines, it is possible to pass flags such as MTX_QUIET 222 * to the appropriate lock manipulation routines. 223 * 224 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 225 * it cannot. Rather, it returns 0 on failure and non-zero on success. 226 * It does NOT handle recursion as we assume that if a caller is properly 227 * using this part of the interface, he will know that the lock in question 228 * is _not_ recursed. 229 * 230 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 231 * relevant option flags `opts.' 232 * 233 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. 234 * 235 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 236 * 237 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 238 */ 239 #define mtx_lock(m) mtx_lock_flags((m), 0) 240 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 241 #define mtx_trylock(m) mtx_trylock_flags((m), 0) 242 #define mtx_unlock(m) mtx_unlock_flags((m), 0) 243 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 244 245 struct mtx_pool; 246 247 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); 248 void mtx_pool_destroy(struct mtx_pool **poolp); 249 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); 250 struct mtx *mtx_pool_alloc(struct mtx_pool *pool); 251 #define mtx_pool_lock(pool, ptr) \ 252 mtx_lock(mtx_pool_find((pool), (ptr))) 253 #define mtx_pool_lock_spin(pool, ptr) \ 254 mtx_lock_spin(mtx_pool_find((pool), (ptr))) 255 #define mtx_pool_unlock(pool, ptr) \ 256 mtx_unlock(mtx_pool_find((pool), (ptr))) 257 #define mtx_pool_unlock_spin(pool, ptr) \ 258 mtx_unlock_spin(mtx_pool_find((pool), (ptr))) 259 260 /* 261 * mtxpool_lockbuilder is a pool of sleep locks that is not witness 262 * checked and should only be used for building higher level locks. 263 * 264 * mtxpool_sleep is a general purpose pool of sleep mutexes. 265 */ 266 extern struct mtx_pool *mtxpool_lockbuilder; 267 extern struct mtx_pool *mtxpool_sleep; 268 269 #ifndef LOCK_DEBUG 270 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h> 271 #endif 272 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) 273 #define mtx_lock_flags(m, opts) \ 274 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 275 #define mtx_unlock_flags(m, opts) \ 276 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 277 #define mtx_lock_spin_flags(m, opts) \ 278 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 279 #define mtx_unlock_spin_flags(m, opts) \ 280 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 281 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ 282 #define mtx_lock_flags(m, opts) \ 283 _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 284 #define mtx_unlock_flags(m, opts) \ 285 _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 286 #ifndef SMPnotyet 287 #define mtx_lock_spin_flags(m, opts) \ 288 _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 289 #define mtx_unlock_spin_flags(m, opts) \ 290 _rel_spin_lock((m)) 291 #else /* SMP */ 292 #define mtx_lock_spin_flags(m, opts) critical_enter() 293 #define mtx_unlock_spin_flags(m, opts) critical_exit() 294 #endif /* SMP */ 295 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ 296 297 #define mtx_trylock_flags(m, opts) \ 298 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE) 299 300 #define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED) 301 302 #define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread) 303 304 #define mtx_recursed(m) ((m)->mtx_recurse != 0) 305 306 #define mtx_name(m) ((m)->mtx_object.lo_name) 307 308 /* 309 * Global locks. 310 */ 311 extern struct mtx sched_lock; 312 extern struct mtx Giant; 313 314 /* 315 * Giant lock manipulation and clean exit macros. 316 * Used to replace return with an exit Giant and return. 317 * 318 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 319 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. 320 */ 321 #ifndef DROP_GIANT 322 #define DROP_GIANT() \ 323 do { \ 324 int _giantcnt; \ 325 WITNESS_SAVE_DECL(Giant); \ 326 \ 327 if (mtx_owned(&Giant)) \ 328 WITNESS_SAVE(&Giant.mtx_object, Giant); \ 329 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 330 mtx_unlock(&Giant) 331 332 #define PICKUP_GIANT() \ 333 mtx_assert(&Giant, MA_NOTOWNED); \ 334 while (_giantcnt--) \ 335 mtx_lock(&Giant); \ 336 if (mtx_owned(&Giant)) \ 337 WITNESS_RESTORE(&Giant.mtx_object, Giant); \ 338 } while (0) 339 340 #define PARTIAL_PICKUP_GIANT() \ 341 mtx_assert(&Giant, MA_NOTOWNED); \ 342 while (_giantcnt--) \ 343 mtx_lock(&Giant); \ 344 if (mtx_owned(&Giant)) \ 345 WITNESS_RESTORE(&Giant.mtx_object, Giant) 346 #endif 347 348 /* 349 * Network MPSAFE temporary workarounds. When debug_mpsafenet 350 * is 1 the network is assumed to operate without Giant on the 351 * input path and protocols that require Giant must collect it 352 * on entry. When 0 Giant is grabbed in the network interface 353 * ISR's and in the netisr path and there is no need to grab 354 * the Giant lock. Note that, unlike GIANT_PICKUP() and 355 * GIANT_DROP(), these macros directly wrap mutex operations 356 * without special recursion handling. 357 * 358 * This mechanism is intended as temporary until everything of 359 * importance is properly locked. Note: the semantics for 360 * NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT() 361 * and PICKUP_GIANT(), as they are plain mutex operations 362 * without a recursion counter. 363 */ 364 extern int debug_mpsafenet; /* defined in net/netisr.c */ 365 #define NET_LOCK_GIANT() do { \ 366 if (!debug_mpsafenet) \ 367 mtx_lock(&Giant); \ 368 } while (0) 369 #define NET_UNLOCK_GIANT() do { \ 370 if (!debug_mpsafenet) \ 371 mtx_unlock(&Giant); \ 372 } while (0) 373 #define NET_ASSERT_GIANT() do { \ 374 if (!debug_mpsafenet) \ 375 mtx_assert(&Giant, MA_OWNED); \ 376 } while (0) 377 378 #define UGAR(rval) do { \ 379 int _val = (rval); \ 380 mtx_unlock(&Giant); \ 381 return (_val); \ 382 } while (0) 383 384 struct mtx_args { 385 struct mtx *ma_mtx; 386 const char *ma_desc; 387 int ma_opts; 388 }; 389 390 #define MTX_SYSINIT(name, mtx, desc, opts) \ 391 static struct mtx_args name##_args = { \ 392 (mtx), \ 393 (desc), \ 394 (opts) \ 395 }; \ 396 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 397 mtx_sysinit, &name##_args) 398 399 /* 400 * The INVARIANTS-enabled mtx_assert() functionality. 401 * 402 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 403 * support as _mtx_assert() itself uses them and the latter implies that 404 * _mtx_assert() must build. 405 */ 406 #ifdef INVARIANT_SUPPORT 407 #define MA_OWNED 0x01 408 #define MA_NOTOWNED 0x02 409 #define MA_RECURSED 0x04 410 #define MA_NOTRECURSED 0x08 411 #endif /* INVARIANT_SUPPORT */ 412 413 #ifdef INVARIANTS 414 #define mtx_assert(m, what) \ 415 _mtx_assert((m), (what), __FILE__, __LINE__) 416 417 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED) 418 419 #else /* INVARIANTS */ 420 #define mtx_assert(m, what) 421 #define GIANT_REQUIRED 422 #endif /* INVARIANTS */ 423 424 /* 425 * Common lock type names. 426 */ 427 #define MTX_NETWORK_LOCK "network driver" 428 429 #endif /* _KERNEL */ 430 #endif /* !LOCORE */ 431 #endif /* _SYS_MUTEX_H_ */
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