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