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/9.0/sys/sys/mutex.h 218673 2011-02-14 02:37:27Z alc $ 30 */ 31 32 #ifndef _SYS_MUTEX_H_ 33 #define _SYS_MUTEX_H_ 34 35 #include <sys/queue.h> 36 #include <sys/_lock.h> 37 #include <sys/_mutex.h> 38 39 #ifdef _KERNEL 40 #include <sys/pcpu.h> 41 #include <sys/lock_profile.h> 42 #include <sys/lockstat.h> 43 #include <machine/atomic.h> 44 #include <machine/cpufunc.h> 45 46 /* 47 * Mutex types and options passed to mtx_init(). MTX_QUIET and MTX_DUPOK 48 * can also be passed in. 49 */ 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 56 /* 57 * Option flags passed to certain lock/unlock routines, through the use 58 * of corresponding mtx_{lock,unlock}_flags() interface macros. 59 */ 60 #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */ 61 #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */ 62 63 /* 64 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this, 65 * with the exception of MTX_UNOWNED, applies to spin locks. 66 */ 67 #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */ 68 #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */ 69 #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */ 70 #define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED) 71 72 /* 73 * Value stored in mutex->mtx_lock to denote a destroyed mutex. 74 */ 75 #define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED) 76 77 /* 78 * Prototypes 79 * 80 * NOTE: Functions prepended with `_' (underscore) are exported to other parts 81 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE 82 * and LOCK_LINE. These functions should not be called directly by any 83 * code using the API. Their macros cover their functionality. 84 * 85 * [See below for descriptions] 86 * 87 */ 88 void mtx_init(struct mtx *m, const char *name, const char *type, int opts); 89 void mtx_destroy(struct mtx *m); 90 void mtx_sysinit(void *arg); 91 void mutex_init(void); 92 void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, 93 const char *file, int line); 94 void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line); 95 #ifdef SMP 96 void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, 97 const char *file, int line); 98 #endif 99 void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line); 100 int _mtx_trylock(struct mtx *m, int opts, const char *file, int line); 101 void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line); 102 void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line); 103 void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, 104 int line); 105 void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, 106 int line); 107 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 108 void _mtx_assert(struct mtx *m, int what, const char *file, int line); 109 #endif 110 void _thread_lock_flags(struct thread *, int, const char *, int); 111 112 #define thread_lock(tdp) \ 113 _thread_lock_flags((tdp), 0, __FILE__, __LINE__) 114 #define thread_lock_flags(tdp, opt) \ 115 _thread_lock_flags((tdp), (opt), __FILE__, __LINE__) 116 #define thread_unlock(tdp) \ 117 mtx_unlock_spin((tdp)->td_lock) 118 119 #define mtx_recurse lock_object.lo_data 120 121 /* Very simple operations on mtx_lock. */ 122 123 /* Try to obtain mtx_lock once. */ 124 #define _mtx_obtain_lock(mp, tid) \ 125 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid)) 126 127 /* Try to release mtx_lock if it is unrecursed and uncontested. */ 128 #define _mtx_release_lock(mp, tid) \ 129 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED) 130 131 /* Release mtx_lock quickly, assuming we own it. */ 132 #define _mtx_release_lock_quick(mp) \ 133 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED) 134 135 /* 136 * Full lock operations that are suitable to be inlined in non-debug 137 * kernels. If the lock cannot be acquired or released trivially then 138 * the work is deferred to another function. 139 */ 140 141 /* Lock a normal mutex. */ 142 #define __mtx_lock(mp, tid, opts, file, line) do { \ 143 uintptr_t _tid = (uintptr_t)(tid); \ 144 \ 145 if (!_mtx_obtain_lock((mp), _tid)) \ 146 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \ 147 else \ 148 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \ 149 mp, 0, 0, (file), (line)); \ 150 } while (0) 151 152 /* 153 * Lock a spin mutex. For spinlocks, we handle recursion inline (it 154 * turns out that function calls can be significantly expensive on 155 * some architectures). Since spin locks are not _too_ common, 156 * inlining this code is not too big a deal. 157 */ 158 #ifdef SMP 159 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ 160 uintptr_t _tid = (uintptr_t)(tid); \ 161 \ 162 spinlock_enter(); \ 163 if (!_mtx_obtain_lock((mp), _tid)) { \ 164 if ((mp)->mtx_lock == _tid) \ 165 (mp)->mtx_recurse++; \ 166 else \ 167 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \ 168 } else \ 169 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \ 170 mp, 0, 0, (file), (line)); \ 171 } while (0) 172 #else /* SMP */ 173 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ 174 uintptr_t _tid = (uintptr_t)(tid); \ 175 \ 176 spinlock_enter(); \ 177 if ((mp)->mtx_lock == _tid) \ 178 (mp)->mtx_recurse++; \ 179 else { \ 180 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \ 181 (mp)->mtx_lock = _tid; \ 182 } \ 183 } while (0) 184 #endif /* SMP */ 185 186 /* Unlock a normal mutex. */ 187 #define __mtx_unlock(mp, tid, opts, file, line) do { \ 188 uintptr_t _tid = (uintptr_t)(tid); \ 189 \ 190 if (!_mtx_release_lock((mp), _tid)) \ 191 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 192 } while (0) 193 194 /* 195 * Unlock a spin mutex. For spinlocks, we can handle everything 196 * inline, as it's pretty simple and a function call would be too 197 * expensive (at least on some architectures). Since spin locks are 198 * not _too_ common, inlining this code is not too big a deal. 199 * 200 * Since we always perform a spinlock_enter() when attempting to acquire a 201 * spin lock, we need to always perform a matching spinlock_exit() when 202 * releasing a spin lock. This includes the recursion cases. 203 */ 204 #ifdef SMP 205 #define __mtx_unlock_spin(mp) do { \ 206 if (mtx_recursed((mp))) \ 207 (mp)->mtx_recurse--; \ 208 else { \ 209 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ 210 mp); \ 211 _mtx_release_lock_quick((mp)); \ 212 } \ 213 spinlock_exit(); \ 214 } while (0) 215 #else /* SMP */ 216 #define __mtx_unlock_spin(mp) do { \ 217 if (mtx_recursed((mp))) \ 218 (mp)->mtx_recurse--; \ 219 else { \ 220 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ 221 mp); \ 222 (mp)->mtx_lock = MTX_UNOWNED; \ 223 } \ 224 spinlock_exit(); \ 225 } while (0) 226 #endif /* SMP */ 227 228 /* 229 * Exported lock manipulation interface. 230 * 231 * mtx_lock(m) locks MTX_DEF mutex `m' 232 * 233 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 234 * 235 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 236 * 237 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 238 * 239 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 240 * and passes option flags `opts' to the "hard" function, if required. 241 * With these routines, it is possible to pass flags such as MTX_QUIET 242 * to the appropriate lock manipulation routines. 243 * 244 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 245 * it cannot. Rather, it returns 0 on failure and non-zero on success. 246 * It does NOT handle recursion as we assume that if a caller is properly 247 * using this part of the interface, he will know that the lock in question 248 * is _not_ recursed. 249 * 250 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 251 * relevant option flags `opts.' 252 * 253 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. 254 * 255 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 256 * 257 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 258 */ 259 #define mtx_lock(m) mtx_lock_flags((m), 0) 260 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 261 #define mtx_trylock(m) mtx_trylock_flags((m), 0) 262 #define mtx_unlock(m) mtx_unlock_flags((m), 0) 263 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 264 265 struct mtx_pool; 266 267 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); 268 void mtx_pool_destroy(struct mtx_pool **poolp); 269 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); 270 struct mtx *mtx_pool_alloc(struct mtx_pool *pool); 271 #define mtx_pool_lock(pool, ptr) \ 272 mtx_lock(mtx_pool_find((pool), (ptr))) 273 #define mtx_pool_lock_spin(pool, ptr) \ 274 mtx_lock_spin(mtx_pool_find((pool), (ptr))) 275 #define mtx_pool_unlock(pool, ptr) \ 276 mtx_unlock(mtx_pool_find((pool), (ptr))) 277 #define mtx_pool_unlock_spin(pool, ptr) \ 278 mtx_unlock_spin(mtx_pool_find((pool), (ptr))) 279 280 /* 281 * mtxpool_lockbuilder is a pool of sleep locks that is not witness 282 * checked and should only be used for building higher level locks. 283 * 284 * mtxpool_sleep is a general purpose pool of sleep mutexes. 285 */ 286 extern struct mtx_pool *mtxpool_lockbuilder; 287 extern struct mtx_pool *mtxpool_sleep; 288 289 #ifndef LOCK_DEBUG 290 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h> 291 #endif 292 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) 293 #define mtx_lock_flags(m, opts) \ 294 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 295 #define mtx_unlock_flags(m, opts) \ 296 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 297 #define mtx_lock_spin_flags(m, opts) \ 298 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 299 #define mtx_unlock_spin_flags(m, opts) \ 300 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 301 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ 302 #define mtx_lock_flags(m, opts) \ 303 __mtx_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 304 #define mtx_unlock_flags(m, opts) \ 305 __mtx_unlock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 306 #define mtx_lock_spin_flags(m, opts) \ 307 __mtx_lock_spin((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 308 #define mtx_unlock_spin_flags(m, opts) \ 309 __mtx_unlock_spin((m)) 310 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ 311 312 #define mtx_trylock_flags(m, opts) \ 313 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE) 314 315 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \ 316 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo)) 317 318 #define mtx_initialized(m) lock_initalized(&(m)->lock_object) 319 320 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread) 321 322 #define mtx_recursed(m) ((m)->mtx_recurse != 0) 323 324 #define mtx_name(m) ((m)->lock_object.lo_name) 325 326 /* 327 * Global locks. 328 */ 329 extern struct mtx Giant; 330 extern struct mtx blocked_lock; 331 332 /* 333 * Giant lock manipulation and clean exit macros. 334 * Used to replace return with an exit Giant and return. 335 * 336 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 337 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. 338 */ 339 #ifndef DROP_GIANT 340 #define DROP_GIANT() \ 341 do { \ 342 int _giantcnt = 0; \ 343 WITNESS_SAVE_DECL(Giant); \ 344 \ 345 if (mtx_owned(&Giant)) { \ 346 WITNESS_SAVE(&Giant.lock_object, Giant); \ 347 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 348 mtx_unlock(&Giant); \ 349 } 350 351 #define PICKUP_GIANT() \ 352 PARTIAL_PICKUP_GIANT(); \ 353 } while (0) 354 355 #define PARTIAL_PICKUP_GIANT() \ 356 mtx_assert(&Giant, MA_NOTOWNED); \ 357 if (_giantcnt > 0) { \ 358 while (_giantcnt--) \ 359 mtx_lock(&Giant); \ 360 WITNESS_RESTORE(&Giant.lock_object, Giant); \ 361 } 362 #endif 363 364 #define UGAR(rval) do { \ 365 int _val = (rval); \ 366 mtx_unlock(&Giant); \ 367 return (_val); \ 368 } while (0) 369 370 struct mtx_args { 371 struct mtx *ma_mtx; 372 const char *ma_desc; 373 int ma_opts; 374 }; 375 376 #define MTX_SYSINIT(name, mtx, desc, opts) \ 377 static struct mtx_args name##_args = { \ 378 (mtx), \ 379 (desc), \ 380 (opts) \ 381 }; \ 382 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 383 mtx_sysinit, &name##_args); \ 384 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 385 mtx_destroy, (mtx)) 386 387 /* 388 * The INVARIANTS-enabled mtx_assert() functionality. 389 * 390 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 391 * support as _mtx_assert() itself uses them and the latter implies that 392 * _mtx_assert() must build. 393 */ 394 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 395 #define MA_OWNED LA_XLOCKED 396 #define MA_NOTOWNED LA_UNLOCKED 397 #define MA_RECURSED LA_RECURSED 398 #define MA_NOTRECURSED LA_NOTRECURSED 399 #endif 400 401 #ifdef INVARIANTS 402 #define mtx_assert(m, what) \ 403 _mtx_assert((m), (what), __FILE__, __LINE__) 404 405 #define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED) 406 407 #else /* INVARIANTS */ 408 #define mtx_assert(m, what) (void)0 409 #define GIANT_REQUIRED 410 #endif /* INVARIANTS */ 411 412 /* 413 * Common lock type names. 414 */ 415 #define MTX_NETWORK_LOCK "network driver" 416 417 #endif /* _KERNEL */ 418 #endif /* _SYS_MUTEX_H_ */
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