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/11.2/sys/sys/mutex.h 331722 2018-03-29 02:50:57Z eadler $
   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 #define MTX_NEW         0x00000040      /* Don't check for double-init */
   56 
   57 /*
   58  * Option flags passed to certain lock/unlock routines, through the use
   59  * of corresponding mtx_{lock,unlock}_flags() interface macros.
   60  */
   61 #define MTX_QUIET       LOP_QUIET       /* Don't log a mutex event */
   62 #define MTX_DUPOK       LOP_DUPOK       /* Don't log a duplicate acquire */
   63 
   64 /*
   65  * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
   66  * with the exception of MTX_UNOWNED, applies to spin locks.
   67  */
   68 #define MTX_UNOWNED     0x00000000      /* Cookie for free mutex */
   69 #define MTX_RECURSED    0x00000001      /* lock recursed (for MTX_DEF only) */
   70 #define MTX_CONTESTED   0x00000002      /* lock contested (for MTX_DEF only) */
   71 #define MTX_DESTROYED   0x00000004      /* lock destroyed */
   72 #define MTX_FLAGMASK    (MTX_RECURSED | MTX_CONTESTED | MTX_DESTROYED)
   73 
   74 /*
   75  * Prototypes
   76  *
   77  * NOTE: Functions prepended with `_' (underscore) are exported to other parts
   78  *       of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
   79  *       and LOCK_LINE or for hiding the lock cookie crunching to the
   80  *       consumers. These functions should not be called directly by any
   81  *       code using the API. Their macros cover their functionality.
   82  *       Functions with a `_' suffix are the entrypoint for the common
   83  *       KPI covering both compat shims and fast path case.  These can be
   84  *       used by consumers willing to pass options, file and line
   85  *       informations, in an option-independent way.
   86  *
   87  * [See below for descriptions]
   88  *
   89  */
   90 void    _mtx_init(volatile uintptr_t *c, const char *name, const char *type,
   91             int opts);
   92 void    _mtx_destroy(volatile uintptr_t *c);
   93 void    mtx_sysinit(void *arg);
   94 int     _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF);
   95 int     _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file,
   96             int line);
   97 void    mutex_init(void);
   98 #if LOCK_DEBUG > 0
   99 void    __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
  100             const char *file, int line);
  101 void    __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
  102             const char *file, int line);
  103 #else
  104 void    __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v);
  105 void    __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v);
  106 #endif
  107 
  108 #ifdef SMP
  109 #if LOCK_DEBUG > 0
  110 void    _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts,
  111             const char *file, int line);
  112 #else
  113 void    _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v);
  114 #endif
  115 #endif
  116 void    __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file,
  117             int line);
  118 void    __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file,
  119             int line);
  120 void    __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
  121              int line);
  122 int     __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts,
  123              const char *file, int line);
  124 void    __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts,
  125             const char *file, int line);
  126 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
  127 void    __mtx_assert(const volatile uintptr_t *c, int what, const char *file,
  128             int line);
  129 #endif
  130 void    thread_lock_flags_(struct thread *, int, const char *, int);
  131 #if LOCK_DEBUG > 0
  132 void    _thread_lock(struct thread *td, int opts, const char *file, int line);
  133 #else
  134 void    _thread_lock(struct thread *);
  135 #endif
  136 
  137 #if defined(LOCK_PROFILING) || defined(KLD_MODULE)
  138 #define thread_lock(tdp)                                                \
  139         thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
  140 #elif LOCK_DEBUG > 0
  141 #define thread_lock(tdp)                                                \
  142         _thread_lock((tdp), 0, __FILE__, __LINE__)
  143 #else
  144 #define thread_lock(tdp)                                                \
  145         _thread_lock((tdp))
  146 #endif
  147 
  148 #if LOCK_DEBUG > 0
  149 #define thread_lock_flags(tdp, opt)                                     \
  150         thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
  151 #else
  152 #define thread_lock_flags(tdp, opt)                                     \
  153         _thread_lock(tdp)
  154 #endif
  155 
  156 #define thread_unlock(tdp)                                              \
  157        mtx_unlock_spin((tdp)->td_lock)
  158 
  159 /*
  160  * Top-level macros to provide lock cookie once the actual mtx is passed.
  161  * They will also prevent passing a malformed object to the mtx KPI by
  162  * failing compilation as the mtx_lock reserved member will not be found.
  163  */
  164 #define mtx_init(m, n, t, o)                                            \
  165         _mtx_init(&(m)->mtx_lock, n, t, o)
  166 #define mtx_destroy(m)                                                  \
  167         _mtx_destroy(&(m)->mtx_lock)
  168 #define mtx_trylock_flags_(m, o, f, l)                                  \
  169         _mtx_trylock_flags_(&(m)->mtx_lock, o, f, l)
  170 #if LOCK_DEBUG > 0
  171 #define _mtx_lock_sleep(m, v, o, f, l)                                  \
  172         __mtx_lock_sleep(&(m)->mtx_lock, v, o, f, l)
  173 #define _mtx_unlock_sleep(m, v, o, f, l)                                \
  174         __mtx_unlock_sleep(&(m)->mtx_lock, v, o, f, l)
  175 #else
  176 #define _mtx_lock_sleep(m, v, o, f, l)                                  \
  177         __mtx_lock_sleep(&(m)->mtx_lock, v)
  178 #define _mtx_unlock_sleep(m, v, o, f, l)                                \
  179         __mtx_unlock_sleep(&(m)->mtx_lock, v)
  180 #endif
  181 #ifdef SMP
  182 #if LOCK_DEBUG > 0
  183 #define _mtx_lock_spin(m, v, o, f, l)                                   \
  184         _mtx_lock_spin_cookie(&(m)->mtx_lock, v, o, f, l)
  185 #else
  186 #define _mtx_lock_spin(m, v, o, f, l)                                   \
  187         _mtx_lock_spin_cookie(&(m)->mtx_lock, v)
  188 #endif
  189 #endif
  190 #define _mtx_lock_flags(m, o, f, l)                                     \
  191         __mtx_lock_flags(&(m)->mtx_lock, o, f, l)
  192 #define _mtx_unlock_flags(m, o, f, l)                                   \
  193         __mtx_unlock_flags(&(m)->mtx_lock, o, f, l)
  194 #define _mtx_lock_spin_flags(m, o, f, l)                                \
  195         __mtx_lock_spin_flags(&(m)->mtx_lock, o, f, l)
  196 #define _mtx_trylock_spin_flags(m, o, f, l)                             \
  197         __mtx_trylock_spin_flags(&(m)->mtx_lock, o, f, l)
  198 #define _mtx_unlock_spin_flags(m, o, f, l)                              \
  199         __mtx_unlock_spin_flags(&(m)->mtx_lock, o, f, l)
  200 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
  201 #define _mtx_assert(m, w, f, l)                                         \
  202         __mtx_assert(&(m)->mtx_lock, w, f, l)
  203 #endif
  204 
  205 #define mtx_recurse     lock_object.lo_data
  206 
  207 /* Very simple operations on mtx_lock. */
  208 
  209 /* Try to obtain mtx_lock once. */
  210 #define _mtx_obtain_lock(mp, tid)                                       \
  211         atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
  212 
  213 #define _mtx_obtain_lock_fetch(mp, vp, tid)                             \
  214         atomic_fcmpset_acq_ptr(&(mp)->mtx_lock, vp, (tid))
  215 
  216 /* Try to release mtx_lock if it is unrecursed and uncontested. */
  217 #define _mtx_release_lock(mp, tid)                                      \
  218         atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
  219 
  220 /* Release mtx_lock quickly, assuming we own it. */
  221 #define _mtx_release_lock_quick(mp)                                     \
  222         atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
  223 
  224 #define _mtx_release_lock_fetch(mp, vp)                                 \
  225         atomic_fcmpset_rel_ptr(&(mp)->mtx_lock, (vp), MTX_UNOWNED)
  226 
  227 /*
  228  * Full lock operations that are suitable to be inlined in non-debug
  229  * kernels.  If the lock cannot be acquired or released trivially then
  230  * the work is deferred to another function.
  231  */
  232 
  233 /* Lock a normal mutex. */
  234 #define __mtx_lock(mp, tid, opts, file, line) do {                      \
  235         uintptr_t _tid = (uintptr_t)(tid);                              \
  236         uintptr_t _v = MTX_UNOWNED;                                     \
  237                                                                         \
  238         if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__acquire) ||\
  239             !_mtx_obtain_lock_fetch((mp), &_v, _tid)))                  \
  240                 _mtx_lock_sleep((mp), _v, (opts), (file), (line));      \
  241 } while (0)
  242 
  243 /*
  244  * Lock a spin mutex.  For spinlocks, we handle recursion inline (it
  245  * turns out that function calls can be significantly expensive on
  246  * some architectures).  Since spin locks are not _too_ common,
  247  * inlining this code is not too big a deal.
  248  */
  249 #ifdef SMP
  250 #define __mtx_lock_spin(mp, tid, opts, file, line) do {                 \
  251         uintptr_t _tid = (uintptr_t)(tid);                              \
  252         uintptr_t _v = MTX_UNOWNED;                                     \
  253                                                                         \
  254         spinlock_enter();                                               \
  255         if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire) ||  \
  256             !_mtx_obtain_lock_fetch((mp), &_v, _tid)))                  \
  257                 _mtx_lock_spin((mp), _v, (opts), (file), (line));       \
  258 } while (0)
  259 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__  ({ \
  260         uintptr_t _tid = (uintptr_t)(tid);                              \
  261         int _ret;                                                       \
  262                                                                         \
  263         spinlock_enter();                                               \
  264         if (((mp)->mtx_lock != MTX_UNOWNED || !_mtx_obtain_lock((mp), _tid))) {\
  265                 spinlock_exit();                                        \
  266                 _ret = 0;                                               \
  267         } else {                                                        \
  268                 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire,     \
  269                     mp, 0, 0, file, line);                              \
  270                 _ret = 1;                                               \
  271         }                                                               \
  272         _ret;                                                           \
  273 })
  274 #else /* SMP */
  275 #define __mtx_lock_spin(mp, tid, opts, file, line) do {                 \
  276         uintptr_t _tid = (uintptr_t)(tid);                              \
  277                                                                         \
  278         spinlock_enter();                                               \
  279         if ((mp)->mtx_lock == _tid)                                     \
  280                 (mp)->mtx_recurse++;                                    \
  281         else {                                                          \
  282                 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
  283                 (mp)->mtx_lock = _tid;                                  \
  284         }                                                               \
  285 } while (0)
  286 #define __mtx_trylock_spin(mp, tid, opts, file, line) __extension__  ({ \
  287         uintptr_t _tid = (uintptr_t)(tid);                              \
  288         int _ret;                                                       \
  289                                                                         \
  290         spinlock_enter();                                               \
  291         if ((mp)->mtx_lock != MTX_UNOWNED) {                            \
  292                 spinlock_exit();                                        \
  293                 _ret = 0;                                               \
  294         } else {                                                        \
  295                 (mp)->mtx_lock = _tid;                                  \
  296                 _ret = 1;                                               \
  297         }                                                               \
  298         _ret;                                                           \
  299 })
  300 #endif /* SMP */
  301 
  302 /* Unlock a normal mutex. */
  303 #define __mtx_unlock(mp, tid, opts, file, line) do {                    \
  304         uintptr_t _v = (uintptr_t)(tid);                                \
  305                                                                         \
  306         if (__predict_false(LOCKSTAT_PROFILE_ENABLED(adaptive__release) ||\
  307             !_mtx_release_lock_fetch((mp), &_v)))                       \
  308                 _mtx_unlock_sleep((mp), _v, (opts), (file), (line));    \
  309 } while (0)
  310 
  311 /*
  312  * Unlock a spin mutex.  For spinlocks, we can handle everything
  313  * inline, as it's pretty simple and a function call would be too
  314  * expensive (at least on some architectures).  Since spin locks are
  315  * not _too_ common, inlining this code is not too big a deal.
  316  *
  317  * Since we always perform a spinlock_enter() when attempting to acquire a
  318  * spin lock, we need to always perform a matching spinlock_exit() when
  319  * releasing a spin lock.  This includes the recursion cases.
  320  */
  321 #ifdef SMP
  322 #define __mtx_unlock_spin(mp) do {                                      \
  323         if (mtx_recursed((mp)))                                         \
  324                 (mp)->mtx_recurse--;                                    \
  325         else {                                                          \
  326                 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp);       \
  327                 _mtx_release_lock_quick((mp));                          \
  328         }                                                               \
  329         spinlock_exit();                                                \
  330 } while (0)
  331 #else /* SMP */
  332 #define __mtx_unlock_spin(mp) do {                                      \
  333         if (mtx_recursed((mp)))                                         \
  334                 (mp)->mtx_recurse--;                                    \
  335         else {                                                          \
  336                 LOCKSTAT_PROFILE_RELEASE_LOCK(spin__release, mp);       \
  337                 (mp)->mtx_lock = MTX_UNOWNED;                           \
  338         }                                                               \
  339         spinlock_exit();                                                \
  340 } while (0)
  341 #endif /* SMP */
  342 
  343 /*
  344  * Exported lock manipulation interface.
  345  *
  346  * mtx_lock(m) locks MTX_DEF mutex `m'
  347  *
  348  * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
  349  *
  350  * mtx_unlock(m) unlocks MTX_DEF mutex `m'
  351  *
  352  * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
  353  *
  354  * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
  355  *     and passes option flags `opts' to the "hard" function, if required.
  356  *     With these routines, it is possible to pass flags such as MTX_QUIET
  357  *     to the appropriate lock manipulation routines.
  358  *
  359  * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
  360  *     it cannot. Rather, it returns 0 on failure and non-zero on success.
  361  *     It does NOT handle recursion as we assume that if a caller is properly
  362  *     using this part of the interface, he will know that the lock in question
  363  *     is _not_ recursed.
  364  *
  365  * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
  366  *     relevant option flags `opts.'
  367  *
  368  * mtx_trylock_spin(m) attempts to acquire MTX_SPIN mutex `m' but doesn't
  369  *     spin if it cannot.  Rather, it returns 0 on failure and non-zero on
  370  *     success.  It always returns failure for recursed lock attempts.
  371  *
  372  * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
  373  *
  374  * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
  375  *
  376  * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
  377  */ 
  378 #define mtx_lock(m)             mtx_lock_flags((m), 0)
  379 #define mtx_lock_spin(m)        mtx_lock_spin_flags((m), 0)
  380 #define mtx_trylock(m)          mtx_trylock_flags((m), 0)
  381 #define mtx_trylock_spin(m)     mtx_trylock_spin_flags((m), 0)
  382 #define mtx_unlock(m)           mtx_unlock_flags((m), 0)
  383 #define mtx_unlock_spin(m)      mtx_unlock_spin_flags((m), 0)
  384 
  385 struct mtx_pool;
  386 
  387 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
  388 void mtx_pool_destroy(struct mtx_pool **poolp);
  389 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
  390 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
  391 #define mtx_pool_lock(pool, ptr)                                        \
  392         mtx_lock(mtx_pool_find((pool), (ptr)))
  393 #define mtx_pool_lock_spin(pool, ptr)                                   \
  394         mtx_lock_spin(mtx_pool_find((pool), (ptr)))
  395 #define mtx_pool_unlock(pool, ptr)                                      \
  396         mtx_unlock(mtx_pool_find((pool), (ptr)))
  397 #define mtx_pool_unlock_spin(pool, ptr)                                 \
  398         mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
  399 
  400 /*
  401  * mtxpool_sleep is a general purpose pool of sleep mutexes.
  402  */
  403 extern struct mtx_pool *mtxpool_sleep;
  404 
  405 #ifndef LOCK_DEBUG
  406 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
  407 #endif
  408 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
  409 #define mtx_lock_flags_(m, opts, file, line)                            \
  410         _mtx_lock_flags((m), (opts), (file), (line))
  411 #define mtx_unlock_flags_(m, opts, file, line)                          \
  412         _mtx_unlock_flags((m), (opts), (file), (line))
  413 #define mtx_lock_spin_flags_(m, opts, file, line)                       \
  414         _mtx_lock_spin_flags((m), (opts), (file), (line))
  415 #define mtx_trylock_spin_flags_(m, opts, file, line)                    \
  416         _mtx_trylock_spin_flags((m), (opts), (file), (line))
  417 #define mtx_unlock_spin_flags_(m, opts, file, line)                     \
  418         _mtx_unlock_spin_flags((m), (opts), (file), (line))
  419 #else   /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
  420 #define mtx_lock_flags_(m, opts, file, line)                            \
  421         __mtx_lock((m), curthread, (opts), (file), (line))
  422 #define mtx_unlock_flags_(m, opts, file, line)                          \
  423         __mtx_unlock((m), curthread, (opts), (file), (line))
  424 #define mtx_lock_spin_flags_(m, opts, file, line)                       \
  425         __mtx_lock_spin((m), curthread, (opts), (file), (line))
  426 #define mtx_trylock_spin_flags_(m, opts, file, line)                    \
  427         __mtx_trylock_spin((m), curthread, (opts), (file), (line))
  428 #define mtx_unlock_spin_flags_(m, opts, file, line)                     \
  429         __mtx_unlock_spin((m))
  430 #endif  /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
  431 
  432 #ifdef INVARIANTS
  433 #define mtx_assert_(m, what, file, line)                                \
  434         _mtx_assert((m), (what), (file), (line))
  435 
  436 #define GIANT_REQUIRED  mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
  437 
  438 #else   /* INVARIANTS */
  439 #define mtx_assert_(m, what, file, line)        (void)0
  440 #define GIANT_REQUIRED
  441 #endif  /* INVARIANTS */
  442 
  443 #define mtx_lock_flags(m, opts)                                         \
  444         mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  445 #define mtx_unlock_flags(m, opts)                                       \
  446         mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  447 #define mtx_lock_spin_flags(m, opts)                                    \
  448         mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  449 #define mtx_unlock_spin_flags(m, opts)                                  \
  450         mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  451 #define mtx_trylock_flags(m, opts)                                      \
  452         mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  453 #define mtx_trylock_spin_flags(m, opts)                                 \
  454         mtx_trylock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
  455 #define mtx_assert(m, what)                                             \
  456         mtx_assert_((m), (what), __FILE__, __LINE__)
  457 
  458 #define mtx_sleep(chan, mtx, pri, wmesg, timo)                          \
  459         _sleep((chan), &(mtx)->lock_object, (pri), (wmesg),             \
  460             tick_sbt * (timo), 0, C_HARDCLOCK)
  461 
  462 #define MTX_READ_VALUE(m)       ((m)->mtx_lock)
  463 
  464 #define mtx_initialized(m)      lock_initialized(&(m)->lock_object)
  465 
  466 #define lv_mtx_owner(v) ((struct thread *)((v) & ~MTX_FLAGMASK))
  467 
  468 #define mtx_owner(m)    lv_mtx_owner(MTX_READ_VALUE(m))
  469 
  470 #define mtx_owned(m)    (mtx_owner(m) == curthread)
  471 
  472 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
  473 
  474 #define mtx_name(m)     ((m)->lock_object.lo_name)
  475 
  476 /*
  477  * Global locks.
  478  */
  479 extern struct mtx Giant;
  480 extern struct mtx blocked_lock;
  481 
  482 /*
  483  * Giant lock manipulation and clean exit macros.
  484  * Used to replace return with an exit Giant and return.
  485  *
  486  * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 
  487  * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
  488  */
  489 #ifndef DROP_GIANT
  490 #define DROP_GIANT()                                                    \
  491 do {                                                                    \
  492         int _giantcnt = 0;                                              \
  493         WITNESS_SAVE_DECL(Giant);                                       \
  494                                                                         \
  495         if (mtx_owned(&Giant)) {                                        \
  496                 WITNESS_SAVE(&Giant.lock_object, Giant);                \
  497                 for (_giantcnt = 0; mtx_owned(&Giant) &&                \
  498                     !SCHEDULER_STOPPED(); _giantcnt++)                  \
  499                         mtx_unlock(&Giant);                             \
  500         }
  501 
  502 #define PICKUP_GIANT()                                                  \
  503         PARTIAL_PICKUP_GIANT();                                         \
  504 } while (0)
  505 
  506 #define PARTIAL_PICKUP_GIANT()                                          \
  507         mtx_assert(&Giant, MA_NOTOWNED);                                \
  508         if (_giantcnt > 0) {                                            \
  509                 while (_giantcnt--)                                     \
  510                         mtx_lock(&Giant);                               \
  511                 WITNESS_RESTORE(&Giant.lock_object, Giant);             \
  512         }
  513 #endif
  514 
  515 struct mtx_args {
  516         void            *ma_mtx;
  517         const char      *ma_desc;
  518         int              ma_opts;
  519 };
  520 
  521 #define MTX_SYSINIT(name, mtx, desc, opts)                              \
  522         static struct mtx_args name##_args = {                          \
  523                 (mtx),                                                  \
  524                 (desc),                                                 \
  525                 (opts)                                                  \
  526         };                                                              \
  527         SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,       \
  528             mtx_sysinit, &name##_args);                                 \
  529         SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,   \
  530             _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
  531 
  532 /*
  533  * The INVARIANTS-enabled mtx_assert() functionality.
  534  *
  535  * The constants need to be defined for INVARIANT_SUPPORT infrastructure
  536  * support as _mtx_assert() itself uses them and the latter implies that
  537  * _mtx_assert() must build.
  538  */
  539 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
  540 #define MA_OWNED        LA_XLOCKED
  541 #define MA_NOTOWNED     LA_UNLOCKED
  542 #define MA_RECURSED     LA_RECURSED
  543 #define MA_NOTRECURSED  LA_NOTRECURSED
  544 #endif
  545 
  546 /*
  547  * Common lock type names.
  548  */
  549 #define MTX_NETWORK_LOCK        "network driver"
  550 
  551 #endif  /* _KERNEL */
  552 #endif  /* _SYS_MUTEX_H_ */

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