FreeBSD-5.3/sys/sys/mutex.h
/*-
* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
* $FreeBSD: src/sys/sys/mutex.h,v 1.73 2004/08/04 20:18:45 jhb Exp $
*/
#ifndef _SYS_MUTEX_H_
#define _SYS_MUTEX_H_
#ifndef LOCORE
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#ifdef _KERNEL
#include <sys/pcpu.h>
#include <machine/atomic.h>
#include <machine/cpufunc.h>
#endif /* _KERNEL_ */
#endif /* !LOCORE */
#include <machine/mutex.h>
#ifdef _KERNEL
/*
* Mutex types and options passed to mtx_init(). MTX_QUIET can also be
* passed in.
*/
#define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
#define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
#define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
#define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
#define MTX_DUPOK 0x00000020 /* Don't log a duplicate acquire */
/*
* Option flags passed to certain lock/unlock routines, through the use
* of corresponding mtx_{lock,unlock}_flags() interface macros.
*/
#define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
/*
* State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
* with the exception of MTX_UNOWNED, applies to spin locks.
*/
#define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
#define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
#define MTX_FLAGMASK ~(MTX_RECURSED | MTX_CONTESTED)
#endif /* _KERNEL */
#ifndef LOCORE
/*
* XXX: Friendly reminder to fix things in MP code that is presently being
* XXX: worked on.
*/
#define mp_fixme(string)
#ifdef _KERNEL
/*
* Prototypes
*
* NOTE: Functions prepended with `_' (underscore) are exported to other parts
* of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
* and LOCK_LINE. These functions should not be called directly by any
* code using the API. Their macros cover their functionality.
*
* [See below for descriptions]
*
*/
void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
void mtx_destroy(struct mtx *m);
void mtx_sysinit(void *arg);
void mutex_init(void);
void _mtx_lock_sleep(struct mtx *m, struct thread *td, int opts,
const char *file, int line);
void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
void _mtx_lock_spin(struct mtx *m, struct thread *td, int opts,
const char *file, int line);
void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
int line);
void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
int line);
#ifdef INVARIANT_SUPPORT
void _mtx_assert(struct mtx *m, int what, const char *file, int line);
#endif
/*
* We define our machine-independent (unoptimized) mutex micro-operations
* here, if they are not already defined in the machine-dependent mutex.h
*/
/* Actually obtain mtx_lock */
#ifndef _obtain_lock
#define _obtain_lock(mp, tid) \
atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid))
#endif
/* Actually release mtx_lock */
#ifndef _release_lock
#define _release_lock(mp, tid) \
atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED)
#endif
/* Actually release mtx_lock quickly, assuming we own it. */
#ifndef _release_lock_quick
#define _release_lock_quick(mp) \
atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED)
#endif
/*
* Obtain a sleep lock inline, or call the "hard" function if we can't get it
* easy.
*/
#ifndef _get_sleep_lock
#define _get_sleep_lock(mp, tid, opts, file, line) do { \
struct thread *_tid = (tid); \
\
if (!_obtain_lock((mp), _tid)) \
_mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
} while (0)
#endif
/*
* Obtain a spin lock inline, or call the "hard" function if we can't get it
* easy. For spinlocks, we handle recursion inline (it turns out that function
* calls can be significantly expensive on some architectures).
* Since spin locks are not _too_ common, inlining this code is not too big
* a deal.
*/
#ifndef _get_spin_lock
#define _get_spin_lock(mp, tid, opts, file, line) do { \
struct thread *_tid = (tid); \
\
critical_enter(); \
if (!_obtain_lock((mp), _tid)) { \
if ((mp)->mtx_lock == (uintptr_t)_tid) \
(mp)->mtx_recurse++; \
else \
_mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
} \
} while (0)
#endif
/*
* Release a sleep lock inline, or call the "hard" function if we can't do it
* easy.
*/
#ifndef _rel_sleep_lock
#define _rel_sleep_lock(mp, tid, opts, file, line) do { \
if (!_release_lock((mp), (tid))) \
_mtx_unlock_sleep((mp), (opts), (file), (line)); \
} while (0)
#endif
/*
* For spinlocks, we can handle everything inline, as it's pretty simple and
* a function call would be too expensive (at least on some architectures).
* Since spin locks are not _too_ common, inlining this code is not too big
* a deal.
*
* Since we always perform a critical_enter() when attempting to acquire a
* spin lock, we need to always perform a matching critical_exit() when
* releasing a spin lock. This includes the recursion cases.
*/
#ifndef _rel_spin_lock
#define _rel_spin_lock(mp) do { \
if (mtx_recursed((mp))) \
(mp)->mtx_recurse--; \
else \
_release_lock_quick((mp)); \
critical_exit(); \
} while (0)
#endif
/*
* Exported lock manipulation interface.
*
* mtx_lock(m) locks MTX_DEF mutex `m'
*
* mtx_lock_spin(m) locks MTX_SPIN mutex `m'
*
* mtx_unlock(m) unlocks MTX_DEF mutex `m'
*
* mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
*
* mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
* and passes option flags `opts' to the "hard" function, if required.
* With these routines, it is possible to pass flags such as MTX_QUIET
* to the appropriate lock manipulation routines.
*
* mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
* it cannot. Rather, it returns 0 on failure and non-zero on success.
* It does NOT handle recursion as we assume that if a caller is properly
* using this part of the interface, he will know that the lock in question
* is _not_ recursed.
*
* mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
* relevant option flags `opts.'
*
* mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
*
* mtx_owned(m) returns non-zero if the current thread owns the lock `m'
*
* mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
*/
#define mtx_lock(m) mtx_lock_flags((m), 0)
#define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
#define mtx_trylock(m) mtx_trylock_flags((m), 0)
#define mtx_unlock(m) mtx_unlock_flags((m), 0)
#define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
struct mtx_pool;
struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
void mtx_pool_destroy(struct mtx_pool **poolp);
struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
#define mtx_pool_lock(pool, ptr) \
mtx_lock(mtx_pool_find((pool), (ptr)))
#define mtx_pool_lock_spin(pool, ptr) \
mtx_lock_spin(mtx_pool_find((pool), (ptr)))
#define mtx_pool_unlock(pool, ptr) \
mtx_unlock(mtx_pool_find((pool), (ptr)))
#define mtx_pool_unlock_spin(pool, ptr) \
mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
/*
* mtxpool_lockbuilder is a pool of sleep locks that is not witness
* checked and should only be used for building higher level locks.
*
* mtxpool_sleep is a general purpose pool of sleep mutexes.
*/
extern struct mtx_pool *mtxpool_lockbuilder;
extern struct mtx_pool *mtxpool_sleep;
#ifndef LOCK_DEBUG
#error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
#endif
#if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
#define mtx_lock_flags(m, opts) \
_mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
#define mtx_unlock_flags(m, opts) \
_mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
#define mtx_lock_spin_flags(m, opts) \
_mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
#define mtx_unlock_spin_flags(m, opts) \
_mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
#else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
#define mtx_lock_flags(m, opts) \
_get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
#define mtx_unlock_flags(m, opts) \
_rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
#ifndef SMPnotyet
#define mtx_lock_spin_flags(m, opts) \
_get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
#define mtx_unlock_spin_flags(m, opts) \
_rel_spin_lock((m))
#else /* SMP */
#define mtx_lock_spin_flags(m, opts) critical_enter()
#define mtx_unlock_spin_flags(m, opts) critical_exit()
#endif /* SMP */
#endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
#define mtx_trylock_flags(m, opts) \
_mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
#define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED)
#define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread)
#define mtx_recursed(m) ((m)->mtx_recurse != 0)
#define mtx_name(m) ((m)->mtx_object.lo_name)
/*
* Global locks.
*/
extern struct mtx sched_lock;
extern struct mtx Giant;
/*
* Giant lock manipulation and clean exit macros.
* Used to replace return with an exit Giant and return.
*
* Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
* The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
*/
#ifndef DROP_GIANT
#define DROP_GIANT() \
do { \
int _giantcnt; \
WITNESS_SAVE_DECL(Giant); \
\
if (mtx_owned(&Giant)) \
WITNESS_SAVE(&Giant.mtx_object, Giant); \
for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
mtx_unlock(&Giant)
#define PICKUP_GIANT() \
mtx_assert(&Giant, MA_NOTOWNED); \
while (_giantcnt--) \
mtx_lock(&Giant); \
if (mtx_owned(&Giant)) \
WITNESS_RESTORE(&Giant.mtx_object, Giant); \
} while (0)
#define PARTIAL_PICKUP_GIANT() \
mtx_assert(&Giant, MA_NOTOWNED); \
while (_giantcnt--) \
mtx_lock(&Giant); \
if (mtx_owned(&Giant)) \
WITNESS_RESTORE(&Giant.mtx_object, Giant)
#endif
/*
* Network MPSAFE temporary workarounds. When debug_mpsafenet
* is 1 the network is assumed to operate without Giant on the
* input path and protocols that require Giant must collect it
* on entry. When 0 Giant is grabbed in the network interface
* ISR's and in the netisr path and there is no need to grab
* the Giant lock. Note that, unlike GIANT_PICKUP() and
* GIANT_DROP(), these macros directly wrap mutex operations
* without special recursion handling.
*
* This mechanism is intended as temporary until everything of
* importance is properly locked. Note: the semantics for
* NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT()
* and PICKUP_GIANT(), as they are plain mutex operations
* without a recursion counter.
*/
extern int debug_mpsafenet; /* defined in net/netisr.c */
#define NET_LOCK_GIANT() do { \
if (!debug_mpsafenet) \
mtx_lock(&Giant); \
} while (0)
#define NET_UNLOCK_GIANT() do { \
if (!debug_mpsafenet) \
mtx_unlock(&Giant); \
} while (0)
#define NET_ASSERT_GIANT() do { \
if (!debug_mpsafenet) \
mtx_assert(&Giant, MA_OWNED); \
} while (0)
#define UGAR(rval) do { \
int _val = (rval); \
mtx_unlock(&Giant); \
return (_val); \
} while (0)
struct mtx_args {
struct mtx *ma_mtx;
const char *ma_desc;
int ma_opts;
};
#define MTX_SYSINIT(name, mtx, desc, opts) \
static struct mtx_args name##_args = { \
(mtx), \
(desc), \
(opts) \
}; \
SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
mtx_sysinit, &name##_args)
/*
* The INVARIANTS-enabled mtx_assert() functionality.
*
* The constants need to be defined for INVARIANT_SUPPORT infrastructure
* support as _mtx_assert() itself uses them and the latter implies that
* _mtx_assert() must build.
*/
#ifdef INVARIANT_SUPPORT
#define MA_OWNED 0x01
#define MA_NOTOWNED 0x02
#define MA_RECURSED 0x04
#define MA_NOTRECURSED 0x08
#endif /* INVARIANT_SUPPORT */
#ifdef INVARIANTS
#define mtx_assert(m, what) \
_mtx_assert((m), (what), __FILE__, __LINE__)
#define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
#else /* INVARIANTS */
#define mtx_assert(m, what)
#define GIANT_REQUIRED
#endif /* INVARIANTS */
/*
* Common lock type names.
*/
#define MTX_NETWORK_LOCK "network driver"
#endif /* _KERNEL */
#endif /* !LOCORE */
#endif /* _SYS_MUTEX_H_ */