The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/sys/mutex.h

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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/6.2/sys/sys/mutex.h 164286 2006-11-14 20:42:41Z 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 and MTX_DUPOK
   53  * can also be 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 
   60 /*
   61  * Option flags passed to certain lock/unlock routines, through the use
   62  * of corresponding mtx_{lock,unlock}_flags() interface macros.
   63  */
   64 #define MTX_QUIET       LOP_QUIET       /* Don't log a mutex event */
   65 #define MTX_DUPOK       LOP_DUPOK       /* Don't log a duplicate acquire */
   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 /*
   77  * Value stored in mutex->mtx_lock to denote a destroyed mutex.
   78  */
   79 #define MTX_DESTROYED   (MTX_CONTESTED | MTX_UNOWNED)
   80 
   81 #endif  /* _KERNEL */
   82 
   83 #ifndef LOCORE
   84 
   85 /*
   86  * XXX: Friendly reminder to fix things in MP code that is presently being
   87  * XXX: worked on.
   88  */
   89 #define mp_fixme(string)
   90 
   91 #ifdef _KERNEL
   92 
   93 /*
   94  * Prototypes
   95  *
   96  * NOTE: Functions prepended with `_' (underscore) are exported to other parts
   97  *       of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
   98  *       and LOCK_LINE. These functions should not be called directly by any
   99  *       code using the API. Their macros cover their functionality.
  100  *
  101  * [See below for descriptions]
  102  *
  103  */
  104 void    mtx_init(struct mtx *m, const char *name, const char *type, int opts);
  105 void    mtx_destroy(struct mtx *m);
  106 void    mtx_sysinit(void *arg);
  107 void    mutex_init(void);
  108 void    _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts,
  109             const char *file, int line);
  110 void    _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
  111 #ifdef SMP
  112 void    _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts,
  113             const char *file, int line);
  114 #endif
  115 void    _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
  116 int     _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
  117 void    _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
  118 void    _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
  119 void    _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
  120              int line);
  121 void    _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
  122              int line);
  123 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
  124 void    _mtx_assert(struct mtx *m, int what, const char *file, int line);
  125 #endif
  126 
  127 /*
  128  * We define our machine-independent (unoptimized) mutex micro-operations
  129  * here, if they are not already defined in the machine-dependent mutex.h 
  130  */
  131 
  132 /* Try to obtain mtx_lock once. */
  133 #ifndef _obtain_lock
  134 #define _obtain_lock(mp, tid)                                           \
  135         atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid))
  136 #endif
  137 
  138 /* Try to release mtx_lock if it is unrecursed and uncontested. */
  139 #ifndef _release_lock
  140 #define _release_lock(mp, tid)                                          \
  141         atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED)
  142 #endif
  143 
  144 /* Release mtx_lock quickly, assuming we own it. */
  145 #ifndef _release_lock_quick
  146 #define _release_lock_quick(mp)                                         \
  147         atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED)
  148 #endif
  149 
  150 /*
  151  * Obtain a sleep lock inline, or call the "hard" function if we can't get it
  152  * easy.
  153  */
  154 #ifndef _get_sleep_lock
  155 #define _get_sleep_lock(mp, tid, opts, file, line) do {                 \
  156         uintptr_t _tid = (uintptr_t)(tid);                              \
  157                                                                         \
  158         if (!_obtain_lock((mp), _tid))                                  \
  159                 _mtx_lock_sleep((mp), _tid, (opts), (file), (line));    \
  160 } while (0)
  161 #endif
  162 
  163 /*
  164  * Obtain a spin lock inline, or call the "hard" function if we can't get it
  165  * easy. For spinlocks, we handle recursion inline (it turns out that function
  166  * calls can be significantly expensive on some architectures).
  167  * Since spin locks are not _too_ common, inlining this code is not too big 
  168  * a deal.
  169  */
  170 #ifndef _get_spin_lock
  171 #ifdef SMP
  172 #define _get_spin_lock(mp, tid, opts, file, line) do {                  \
  173         uintptr_t _tid = (uintptr_t)(tid);                              \
  174                                                                         \
  175         spinlock_enter();                                               \
  176         if (!_obtain_lock((mp), _tid)) {                                \
  177                 if ((mp)->mtx_lock == _tid)                             \
  178                         (mp)->mtx_recurse++;                            \
  179                 else                                                    \
  180                         _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
  181         }                                                               \
  182 } while (0)
  183 #else /* SMP */
  184 #define _get_spin_lock(mp, tid, opts, file, line) do {                  \
  185         uintptr_t _tid = (uintptr_t)(tid);                              \
  186                                                                         \
  187         spinlock_enter();                                               \
  188         if ((mp)->mtx_lock == _tid)                                     \
  189                 (mp)->mtx_recurse++;                                    \
  190         else {                                                          \
  191                 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
  192                 (mp)->mtx_lock = _tid;                          \
  193         }                                                               \
  194 } while (0)
  195 #endif /* SMP */
  196 #endif
  197 
  198 /*
  199  * Release a sleep lock inline, or call the "hard" function if we can't do it
  200  * easy.
  201  */
  202 #ifndef _rel_sleep_lock
  203 #define _rel_sleep_lock(mp, tid, opts, file, line) do {                 \
  204         uintptr_t _tid = (uintptr_t)(tid);                              \
  205                                                                         \
  206         if (!_release_lock((mp), _tid))                                 \
  207                 _mtx_unlock_sleep((mp), (opts), (file), (line));        \
  208 } while (0)
  209 #endif
  210 
  211 /*
  212  * For spinlocks, we can handle everything inline, as it's pretty simple and
  213  * a function call would be too expensive (at least on some architectures).
  214  * Since spin locks are not _too_ common, inlining this code is not too big 
  215  * a deal.
  216  *
  217  * Since we always perform a spinlock_enter() when attempting to acquire a
  218  * spin lock, we need to always perform a matching spinlock_exit() when
  219  * releasing a spin lock.  This includes the recursion cases.
  220  */
  221 #ifndef _rel_spin_lock
  222 #ifdef SMP
  223 #define _rel_spin_lock(mp) do {                                         \
  224         if (mtx_recursed((mp)))                                         \
  225                 (mp)->mtx_recurse--;                                    \
  226         else                                                            \
  227                 _release_lock_quick((mp));                              \
  228         spinlock_exit();                                                \
  229 } while (0)
  230 #else /* SMP */
  231 #define _rel_spin_lock(mp) do {                                         \
  232         if (mtx_recursed((mp)))                                         \
  233                 (mp)->mtx_recurse--;                                    \
  234         else                                                            \
  235                 (mp)->mtx_lock = MTX_UNOWNED;                           \
  236         spinlock_exit();                                                \
  237 } while (0)
  238 #endif /* SMP */
  239 #endif
  240 
  241 /*
  242  * Exported lock manipulation interface.
  243  *
  244  * mtx_lock(m) locks MTX_DEF mutex `m'
  245  *
  246  * mtx_lock_spin(m) locks MTX_SPIN mutex `m'
  247  *
  248  * mtx_unlock(m) unlocks MTX_DEF mutex `m'
  249  *
  250  * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
  251  *
  252  * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
  253  *     and passes option flags `opts' to the "hard" function, if required.
  254  *     With these routines, it is possible to pass flags such as MTX_QUIET
  255  *     to the appropriate lock manipulation routines.
  256  *
  257  * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
  258  *     it cannot. Rather, it returns 0 on failure and non-zero on success.
  259  *     It does NOT handle recursion as we assume that if a caller is properly
  260  *     using this part of the interface, he will know that the lock in question
  261  *     is _not_ recursed.
  262  *
  263  * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
  264  *     relevant option flags `opts.'
  265  *
  266  * mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
  267  *
  268  * mtx_owned(m) returns non-zero if the current thread owns the lock `m'
  269  *
  270  * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
  271  */ 
  272 #define mtx_lock(m)             mtx_lock_flags((m), 0)
  273 #define mtx_lock_spin(m)        mtx_lock_spin_flags((m), 0)
  274 #define mtx_trylock(m)          mtx_trylock_flags((m), 0)
  275 #define mtx_unlock(m)           mtx_unlock_flags((m), 0)
  276 #define mtx_unlock_spin(m)      mtx_unlock_spin_flags((m), 0)
  277 
  278 struct mtx_pool;
  279 
  280 struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
  281 void mtx_pool_destroy(struct mtx_pool **poolp);
  282 struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
  283 struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
  284 #define mtx_pool_lock(pool, ptr)                                        \
  285         mtx_lock(mtx_pool_find((pool), (ptr)))
  286 #define mtx_pool_lock_spin(pool, ptr)                                   \
  287         mtx_lock_spin(mtx_pool_find((pool), (ptr)))
  288 #define mtx_pool_unlock(pool, ptr)                                      \
  289         mtx_unlock(mtx_pool_find((pool), (ptr)))
  290 #define mtx_pool_unlock_spin(pool, ptr)                                 \
  291         mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
  292 
  293 /*
  294  * mtxpool_lockbuilder is a pool of sleep locks that is not witness
  295  * checked and should only be used for building higher level locks.
  296  *
  297  * mtxpool_sleep is a general purpose pool of sleep mutexes.
  298  */
  299 extern struct mtx_pool *mtxpool_lockbuilder;
  300 extern struct mtx_pool *mtxpool_sleep;
  301 
  302 #ifndef LOCK_DEBUG
  303 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
  304 #endif
  305 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
  306 #define mtx_lock_flags(m, opts)                                         \
  307         _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
  308 #define mtx_unlock_flags(m, opts)                                       \
  309         _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
  310 #define mtx_lock_spin_flags(m, opts)                                    \
  311         _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
  312 #define mtx_unlock_spin_flags(m, opts)                                  \
  313         _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
  314 #else   /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
  315 #define mtx_lock_flags(m, opts)                                         \
  316         _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
  317 #define mtx_unlock_flags(m, opts)                                       \
  318         _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
  319 #define mtx_lock_spin_flags(m, opts)                                    \
  320         _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
  321 #define mtx_unlock_spin_flags(m, opts)                                  \
  322         _rel_spin_lock((m))
  323 #endif  /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
  324 
  325 #define mtx_trylock_flags(m, opts)                                      \
  326         _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
  327 
  328 #define mtx_initialized(m)      lock_initalized(&(m)->mtx_object)
  329 
  330 #define mtx_owned(m)    (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread)
  331 
  332 #define mtx_recursed(m) ((m)->mtx_recurse != 0)
  333 
  334 #define mtx_name(m)     ((m)->mtx_object.lo_name)
  335 
  336 /*
  337  * Global locks.
  338  */
  339 extern struct mtx sched_lock;
  340 extern struct mtx Giant;
  341 
  342 /*
  343  * Giant lock manipulation and clean exit macros.
  344  * Used to replace return with an exit Giant and return.
  345  *
  346  * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 
  347  * The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
  348  */
  349 #ifndef DROP_GIANT
  350 #define DROP_GIANT()                                                    \
  351 do {                                                                    \
  352         int _giantcnt;                                                  \
  353         WITNESS_SAVE_DECL(Giant);                                       \
  354                                                                         \
  355         if (mtx_owned(&Giant))                                          \
  356                 WITNESS_SAVE(&Giant.mtx_object, Giant);                 \
  357         for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++)             \
  358                 mtx_unlock(&Giant)
  359 
  360 #define PICKUP_GIANT()                                                  \
  361         mtx_assert(&Giant, MA_NOTOWNED);                                \
  362         while (_giantcnt--)                                             \
  363                 mtx_lock(&Giant);                                       \
  364         if (mtx_owned(&Giant))                                          \
  365                 WITNESS_RESTORE(&Giant.mtx_object, Giant);              \
  366 } while (0)
  367 
  368 #define PARTIAL_PICKUP_GIANT()                                          \
  369         mtx_assert(&Giant, MA_NOTOWNED);                                \
  370         while (_giantcnt--)                                             \
  371                 mtx_lock(&Giant);                                       \
  372         if (mtx_owned(&Giant))                                          \
  373                 WITNESS_RESTORE(&Giant.mtx_object, Giant)
  374 #endif
  375 
  376 /*
  377  * Network MPSAFE temporary workarounds.  When debug_mpsafenet
  378  * is 1 the network is assumed to operate without Giant on the
  379  * input path and protocols that require Giant must collect it
  380  * on entry.  When 0 Giant is grabbed in the network interface
  381  * ISR's and in the netisr path and there is no need to grab
  382  * the Giant lock.  Note that, unlike GIANT_PICKUP() and
  383  * GIANT_DROP(), these macros directly wrap mutex operations
  384  * without special recursion handling.
  385  *
  386  * This mechanism is intended as temporary until everything of
  387  * importance is properly locked.  Note: the semantics for
  388  * NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT()
  389  * and PICKUP_GIANT(), as they are plain mutex operations
  390  * without a recursion counter.
  391  */
  392 extern  int debug_mpsafenet;            /* defined in net/netisr.c */
  393 #define NET_LOCK_GIANT() do {                                           \
  394         if (!debug_mpsafenet)                                           \
  395                 mtx_lock(&Giant);                                       \
  396 } while (0)
  397 #define NET_UNLOCK_GIANT() do {                                         \
  398         if (!debug_mpsafenet)                                           \
  399                 mtx_unlock(&Giant);                                     \
  400 } while (0)
  401 #define NET_ASSERT_GIANT() do {                                         \
  402         if (!debug_mpsafenet)                                           \
  403                 mtx_assert(&Giant, MA_OWNED);                           \
  404 } while (0)
  405 #define NET_CALLOUT_MPSAFE      (debug_mpsafenet ? CALLOUT_MPSAFE : 0)
  406 
  407 #define UGAR(rval) do {                                                 \
  408         int _val = (rval);                                              \
  409         mtx_unlock(&Giant);                                             \
  410         return (_val);                                                  \
  411 } while (0)
  412 
  413 struct mtx_args {
  414         struct mtx      *ma_mtx;
  415         const char      *ma_desc;
  416         int              ma_opts;
  417 };
  418 
  419 #define MTX_SYSINIT(name, mtx, desc, opts)                              \
  420         static struct mtx_args name##_args = {                          \
  421                 (mtx),                                                  \
  422                 (desc),                                                 \
  423                 (opts)                                                  \
  424         };                                                              \
  425         SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,       \
  426             mtx_sysinit, &name##_args);                                 \
  427         SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,   \
  428             mtx_destroy, (mtx))
  429 
  430 /*
  431  * The INVARIANTS-enabled mtx_assert() functionality.
  432  *
  433  * The constants need to be defined for INVARIANT_SUPPORT infrastructure
  434  * support as _mtx_assert() itself uses them and the latter implies that
  435  * _mtx_assert() must build.
  436  */
  437 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
  438 #define MA_OWNED        0x01
  439 #define MA_NOTOWNED     0x02
  440 #define MA_RECURSED     0x04
  441 #define MA_NOTRECURSED  0x08
  442 #endif
  443 
  444 #ifdef INVARIANTS
  445 #define mtx_assert(m, what)                                             \
  446         _mtx_assert((m), (what), __FILE__, __LINE__)
  447 
  448 #define GIANT_REQUIRED  mtx_assert(&Giant, MA_OWNED)
  449 
  450 #else   /* INVARIANTS */
  451 #define mtx_assert(m, what)
  452 #define GIANT_REQUIRED
  453 #endif  /* INVARIANTS */
  454 
  455 /*
  456  * Common lock type names.
  457  */
  458 #define MTX_NETWORK_LOCK        "network driver"
  459 
  460 #endif  /* _KERNEL */
  461 #endif  /* !LOCORE */
  462 #endif  /* _SYS_MUTEX_H_ */

Cache object: 236e0bb00d19e96b9257baa9093c989e


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.