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/10.3/sys/sys/mutex.h 251220 2013-06-01 11:31:09Z jhb $ 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 or for hiding the lock cookie crunching to the 83 * consumers. These functions should not be called directly by any 84 * code using the API. Their macros cover their functionality. 85 * Functions with a `_' suffix are the entrypoint for the common 86 * KPI covering both compat shims and fast path case. These can be 87 * used by consumers willing to pass options, file and line 88 * informations, in an option-independent way. 89 * 90 * [See below for descriptions] 91 * 92 */ 93 void _mtx_init(volatile uintptr_t *c, const char *name, const char *type, 94 int opts); 95 void _mtx_destroy(volatile uintptr_t *c); 96 void mtx_sysinit(void *arg); 97 int _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, 98 int line); 99 void mutex_init(void); 100 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t tid, int opts, 101 const char *file, int line); 102 void __mtx_unlock_sleep(volatile uintptr_t *c, int opts, const char *file, 103 int line); 104 #ifdef SMP 105 void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts, 106 const char *file, int line); 107 #endif 108 void __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, 109 int line); 110 void __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, 111 int line); 112 void __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 113 int line); 114 void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, 115 const char *file, int line); 116 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 117 void __mtx_assert(const volatile uintptr_t *c, int what, const char *file, 118 int line); 119 #endif 120 void thread_lock_flags_(struct thread *, int, const char *, int); 121 122 #define thread_lock(tdp) \ 123 thread_lock_flags_((tdp), 0, __FILE__, __LINE__) 124 #define thread_lock_flags(tdp, opt) \ 125 thread_lock_flags_((tdp), (opt), __FILE__, __LINE__) 126 #define thread_unlock(tdp) \ 127 mtx_unlock_spin((tdp)->td_lock) 128 129 /* 130 * Top-level macros to provide lock cookie once the actual mtx is passed. 131 * They will also prevent passing a malformed object to the mtx KPI by 132 * failing compilation as the mtx_lock reserved member will not be found. 133 */ 134 #define mtx_init(m, n, t, o) \ 135 _mtx_init(&(m)->mtx_lock, n, t, o) 136 #define mtx_destroy(m) \ 137 _mtx_destroy(&(m)->mtx_lock) 138 #define mtx_trylock_flags_(m, o, f, l) \ 139 _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l) 140 #define _mtx_lock_sleep(m, t, o, f, l) \ 141 __mtx_lock_sleep(&(m)->mtx_lock, t, o, f, l) 142 #define _mtx_unlock_sleep(m, o, f, l) \ 143 __mtx_unlock_sleep(&(m)->mtx_lock, o, f, l) 144 #ifdef SMP 145 #define _mtx_lock_spin(m, t, o, f, l) \ 146 _mtx_lock_spin_cookie(&(m)->mtx_lock, t, o, f, l) 147 #endif 148 #define _mtx_lock_flags(m, o, f, l) \ 149 __mtx_lock_flags(&(m)->mtx_lock, o, f, l) 150 #define _mtx_unlock_flags(m, o, f, l) \ 151 __mtx_unlock_flags(&(m)->mtx_lock, o, f, l) 152 #define _mtx_lock_spin_flags(m, o, f, l) \ 153 __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l) 154 #define _mtx_unlock_spin_flags(m, o, f, l) \ 155 __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l) 156 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 157 #define _mtx_assert(m, w, f, l) \ 158 __mtx_assert(&(m)->mtx_lock, w, f, l) 159 #endif 160 161 #define mtx_recurse lock_object.lo_data 162 163 /* Very simple operations on mtx_lock. */ 164 165 /* Try to obtain mtx_lock once. */ 166 #define _mtx_obtain_lock(mp, tid) \ 167 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid)) 168 169 /* Try to release mtx_lock if it is unrecursed and uncontested. */ 170 #define _mtx_release_lock(mp, tid) \ 171 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED) 172 173 /* Release mtx_lock quickly, assuming we own it. */ 174 #define _mtx_release_lock_quick(mp) \ 175 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED) 176 177 /* 178 * Full lock operations that are suitable to be inlined in non-debug 179 * kernels. If the lock cannot be acquired or released trivially then 180 * the work is deferred to another function. 181 */ 182 183 /* Lock a normal mutex. */ 184 #define __mtx_lock(mp, tid, opts, file, line) do { \ 185 uintptr_t _tid = (uintptr_t)(tid); \ 186 \ 187 if (!_mtx_obtain_lock((mp), _tid)) \ 188 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \ 189 else \ 190 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \ 191 mp, 0, 0, (file), (line)); \ 192 } while (0) 193 194 /* 195 * Lock a spin mutex. For spinlocks, we handle recursion inline (it 196 * turns out that function calls can be significantly expensive on 197 * some architectures). Since spin locks are not _too_ common, 198 * inlining this code is not too big a deal. 199 */ 200 #ifdef SMP 201 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ 202 uintptr_t _tid = (uintptr_t)(tid); \ 203 \ 204 spinlock_enter(); \ 205 if (!_mtx_obtain_lock((mp), _tid)) { \ 206 if ((mp)->mtx_lock == _tid) \ 207 (mp)->mtx_recurse++; \ 208 else \ 209 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \ 210 } else \ 211 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \ 212 mp, 0, 0, (file), (line)); \ 213 } while (0) 214 #else /* SMP */ 215 #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ 216 uintptr_t _tid = (uintptr_t)(tid); \ 217 \ 218 spinlock_enter(); \ 219 if ((mp)->mtx_lock == _tid) \ 220 (mp)->mtx_recurse++; \ 221 else { \ 222 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \ 223 (mp)->mtx_lock = _tid; \ 224 } \ 225 } while (0) 226 #endif /* SMP */ 227 228 /* Unlock a normal mutex. */ 229 #define __mtx_unlock(mp, tid, opts, file, line) do { \ 230 uintptr_t _tid = (uintptr_t)(tid); \ 231 \ 232 if (!_mtx_release_lock((mp), _tid)) \ 233 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 234 } while (0) 235 236 /* 237 * Unlock a spin mutex. For spinlocks, we can handle everything 238 * inline, as it's pretty simple and a function call would be too 239 * expensive (at least on some architectures). Since spin locks are 240 * not _too_ common, inlining this code is not too big a deal. 241 * 242 * Since we always perform a spinlock_enter() when attempting to acquire a 243 * spin lock, we need to always perform a matching spinlock_exit() when 244 * releasing a spin lock. This includes the recursion cases. 245 */ 246 #ifdef SMP 247 #define __mtx_unlock_spin(mp) do { \ 248 if (mtx_recursed((mp))) \ 249 (mp)->mtx_recurse--; \ 250 else { \ 251 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ 252 mp); \ 253 _mtx_release_lock_quick((mp)); \ 254 } \ 255 spinlock_exit(); \ 256 } while (0) 257 #else /* SMP */ 258 #define __mtx_unlock_spin(mp) do { \ 259 if (mtx_recursed((mp))) \ 260 (mp)->mtx_recurse--; \ 261 else { \ 262 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ 263 mp); \ 264 (mp)->mtx_lock = MTX_UNOWNED; \ 265 } \ 266 spinlock_exit(); \ 267 } while (0) 268 #endif /* SMP */ 269 270 /* 271 * Exported lock manipulation interface. 272 * 273 * mtx_lock(m) locks MTX_DEF mutex `m' 274 * 275 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 276 * 277 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 278 * 279 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 280 * 281 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 282 * and passes option flags `opts' to the "hard" function, if required. 283 * With these routines, it is possible to pass flags such as MTX_QUIET 284 * to the appropriate lock manipulation routines. 285 * 286 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 287 * it cannot. Rather, it returns 0 on failure and non-zero on success. 288 * It does NOT handle recursion as we assume that if a caller is properly 289 * using this part of the interface, he will know that the lock in question 290 * is _not_ recursed. 291 * 292 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 293 * relevant option flags `opts.' 294 * 295 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. 296 * 297 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 298 * 299 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 300 */ 301 #define mtx_lock(m) mtx_lock_flags((m), 0) 302 #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 303 #define mtx_trylock(m) mtx_trylock_flags((m), 0) 304 #define mtx_unlock(m) mtx_unlock_flags((m), 0) 305 #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 306 307 struct mtx_pool; 308 309 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); 310 void mtx_pool_destroy(struct mtx_pool **poolp); 311 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); 312 struct mtx *mtx_pool_alloc(struct mtx_pool *pool); 313 #define mtx_pool_lock(pool, ptr) \ 314 mtx_lock(mtx_pool_find((pool), (ptr))) 315 #define mtx_pool_lock_spin(pool, ptr) \ 316 mtx_lock_spin(mtx_pool_find((pool), (ptr))) 317 #define mtx_pool_unlock(pool, ptr) \ 318 mtx_unlock(mtx_pool_find((pool), (ptr))) 319 #define mtx_pool_unlock_spin(pool, ptr) \ 320 mtx_unlock_spin(mtx_pool_find((pool), (ptr))) 321 322 /* 323 * mtxpool_lockbuilder is a pool of sleep locks that is not witness 324 * checked and should only be used for building higher level locks. 325 * 326 * mtxpool_sleep is a general purpose pool of sleep mutexes. 327 */ 328 extern struct mtx_pool *mtxpool_lockbuilder; 329 extern struct mtx_pool *mtxpool_sleep; 330 331 #ifndef LOCK_DEBUG 332 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h> 333 #endif 334 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) 335 #define mtx_lock_flags_(m, opts, file, line) \ 336 _mtx_lock_flags((m), (opts), (file), (line)) 337 #define mtx_unlock_flags_(m, opts, file, line) \ 338 _mtx_unlock_flags((m), (opts), (file), (line)) 339 #define mtx_lock_spin_flags_(m, opts, file, line) \ 340 _mtx_lock_spin_flags((m), (opts), (file), (line)) 341 #define mtx_unlock_spin_flags_(m, opts, file, line) \ 342 _mtx_unlock_spin_flags((m), (opts), (file), (line)) 343 #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ 344 #define mtx_lock_flags_(m, opts, file, line) \ 345 __mtx_lock((m), curthread, (opts), (file), (line)) 346 #define mtx_unlock_flags_(m, opts, file, line) \ 347 __mtx_unlock((m), curthread, (opts), (file), (line)) 348 #define mtx_lock_spin_flags_(m, opts, file, line) \ 349 __mtx_lock_spin((m), curthread, (opts), (file), (line)) 350 #define mtx_unlock_spin_flags_(m, opts, file, line) \ 351 __mtx_unlock_spin((m)) 352 #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ 353 354 #ifdef INVARIANTS 355 #define mtx_assert_(m, what, file, line) \ 356 _mtx_assert((m), (what), (file), (line)) 357 358 #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__) 359 360 #else /* INVARIANTS */ 361 #define mtx_assert_(m, what, file, line) (void)0 362 #define GIANT_REQUIRED 363 #endif /* INVARIANTS */ 364 365 #define mtx_lock_flags(m, opts) \ 366 mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) 367 #define mtx_unlock_flags(m, opts) \ 368 mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) 369 #define mtx_lock_spin_flags(m, opts) \ 370 mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE) 371 #define mtx_unlock_spin_flags(m, opts) \ 372 mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE) 373 #define mtx_trylock_flags(m, opts) \ 374 mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) 375 #define mtx_assert(m, what) \ 376 mtx_assert_((m), (what), __FILE__, __LINE__) 377 378 #define mtx_sleep(chan, mtx, pri, wmesg, timo) \ 379 _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), \ 380 tick_sbt * (timo), 0, C_HARDCLOCK) 381 382 #define mtx_initialized(m) lock_initalized(&(m)->lock_object) 383 384 #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread) 385 386 #define mtx_recursed(m) ((m)->mtx_recurse != 0) 387 388 #define mtx_name(m) ((m)->lock_object.lo_name) 389 390 /* 391 * Global locks. 392 */ 393 extern struct mtx Giant; 394 extern struct mtx blocked_lock; 395 396 /* 397 * Giant lock manipulation and clean exit macros. 398 * Used to replace return with an exit Giant and return. 399 * 400 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 401 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. 402 */ 403 #ifndef DROP_GIANT 404 #define DROP_GIANT() \ 405 do { \ 406 int _giantcnt = 0; \ 407 WITNESS_SAVE_DECL(Giant); \ 408 \ 409 if (mtx_owned(&Giant)) { \ 410 WITNESS_SAVE(&Giant.lock_object, Giant); \ 411 for (_giantcnt = 0; mtx_owned(&Giant) && \ 412 !SCHEDULER_STOPPED(); _giantcnt++) \ 413 mtx_unlock(&Giant); \ 414 } 415 416 #define PICKUP_GIANT() \ 417 PARTIAL_PICKUP_GIANT(); \ 418 } while (0) 419 420 #define PARTIAL_PICKUP_GIANT() \ 421 mtx_assert(&Giant, MA_NOTOWNED); \ 422 if (_giantcnt > 0) { \ 423 while (_giantcnt--) \ 424 mtx_lock(&Giant); \ 425 WITNESS_RESTORE(&Giant.lock_object, Giant); \ 426 } 427 #endif 428 429 struct mtx_args { 430 void *ma_mtx; 431 const char *ma_desc; 432 int ma_opts; 433 }; 434 435 #define MTX_SYSINIT(name, mtx, desc, opts) \ 436 static struct mtx_args name##_args = { \ 437 (mtx), \ 438 (desc), \ 439 (opts) \ 440 }; \ 441 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 442 mtx_sysinit, &name##_args); \ 443 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 444 _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock)) 445 446 /* 447 * The INVARIANTS-enabled mtx_assert() functionality. 448 * 449 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 450 * support as _mtx_assert() itself uses them and the latter implies that 451 * _mtx_assert() must build. 452 */ 453 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 454 #define MA_OWNED LA_XLOCKED 455 #define MA_NOTOWNED LA_UNLOCKED 456 #define MA_RECURSED LA_RECURSED 457 #define MA_NOTRECURSED LA_NOTRECURSED 458 #endif 459 460 /* 461 * Common lock type names. 462 */ 463 #define MTX_NETWORK_LOCK "network driver" 464 465 #endif /* _KERNEL */ 466 #endif /* _SYS_MUTEX_H_ */
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