4d4057d8a2
. fsck driver parses /etc/fstab and invokes sub-fscks . further simplifies fs handling in rc
216 lines
6.3 KiB
C
216 lines
6.3 KiB
C
/* $NetBSD: mutex.h,v 1.20 2010/02/08 09:54:27 skrll Exp $ */
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/*-
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* Copyright (c) 2002, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe and Andrew Doran.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _SYS_MUTEX_H_
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#define _SYS_MUTEX_H_
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/*
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* There are 2 types of mutexes:
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*
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* * Adaptive -- If the lock is already held, the thread attempting
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* to acquire the lock determines if the thread that holds it is
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* currently running. If so, it spins, else it sleeps.
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*
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* * Spin -- If the lock is already held, the thread attempting to
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* acquire the lock spins. The IPL will be raised on entry.
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*
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* Machine dependent code must provide the following:
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*
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* struct mutex
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* The actual mutex structure. This structure is mostly
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* opaque to machine-independent code; most access are done
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* through macros. However, machine-independent code must
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* be able to access the following members:
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*
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* uintptr_t mtx_owner
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* ipl_cookie_t mtx_ipl
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* __cpu_simple_lock_t mtx_lock
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*
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* If an architecture can be considered 'simple' (no interlock required in
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* the MP case, or no MP) it need only define __HAVE_SIMPLE_MUTEXES and
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* provide the following:
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*
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* struct mutex
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*
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* [additionally:]
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* volatile integer mtx_id
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*
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* MUTEX_RECEIVE(mtx)
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* Post a load fence after acquiring the mutex, if necessary.
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*
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* MUTEX_GIVE(mtx)
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* Post a load/store fence after releasing the mutex, if
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* necessary.
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*
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* MUTEX_CAS(ptr, old, new)
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* Perform an atomic "compare and swap" operation and
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* evaluate to true or false according to the success
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*
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* Otherwise, the following must be defined:
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*
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* MUTEX_INITIALIZE_SPIN(mtx, dodebug, minipl)
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* Initialize a spin mutex.
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*
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* MUTEX_INITIALIZE_ADAPTIVE(mtx, dodebug)
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* Initialize an adaptive mutex.
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*
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* MUTEX_DESTROY(mtx)
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* Tear down a mutex.
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*
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* MUTEX_ADAPTIVE_P(mtx)
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* Evaluates to true if the mutex is an adaptive mutex.
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*
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* MUTEX_SPIN_P(mtx)
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* Evaluates to true if the mutex is a spin mutex.
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*
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* MUTEX_OWNER(owner)
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* Returns the owner of the adaptive mutex (LWP address).
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*
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* MUTEX_OWNED(owner)
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* Returns non-zero if an adaptive mutex is currently
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* held by an LWP.
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*
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* MUTEX_HAS_WAITERS(mtx)
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* Returns true if the mutex has waiters.
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*
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* MUTEX_SET_WAITERS(mtx)
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* Mark the mutex has having waiters.
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*
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* MUTEX_ACQUIRE(mtx, owner)
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* Try to acquire an adaptive mutex such that:
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* if (lock held OR waiters)
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* return 0;
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* else
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* return 1;
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* Must be MP/interrupt atomic.
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*
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* MUTEX_RELEASE(mtx)
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* Release the lock and clear the "has waiters" indication.
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* Must be interrupt atomic, need not be MP safe.
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*
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* MUTEX_DEBUG_P(mtx)
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* Evaluates to true if the mutex is initialized with
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* dodebug==true. Only used in the LOCKDEBUG case.
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*
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* Machine dependent code may optionally provide stubs for the following
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* functions to implement the easy (unlocked / no waiters) cases. If
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* these stubs are provided, __HAVE_MUTEX_STUBS should be defined.
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*
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* mutex_enter()
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* mutex_exit()
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*
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* Two additional stubs may be implemented that handle only the spinlock
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* case, primarily for the scheduler. __HAVE_SPIN_MUTEX_STUBS should be
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* defined if these are provided:
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*
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* mutex_spin_enter()
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* mutex_spin_exit()
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*/
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#if defined(_KERNEL_OPT)
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#include "opt_lockdebug.h"
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#endif
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#if !defined(_KERNEL)
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#include <sys/types.h>
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#include <sys/inttypes.h>
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#endif
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typedef enum kmutex_type_t {
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MUTEX_SPIN = 0, /* To get a spin mutex at IPL_NONE */
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MUTEX_ADAPTIVE = 1, /* For porting code written for Solaris */
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MUTEX_DEFAULT = 2, /* The only native, endorsed type */
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MUTEX_DRIVER = 3, /* For porting code written for Solaris */
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MUTEX_NODEBUG = 4 /* Disables LOCKDEBUG; use with care */
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} kmutex_type_t;
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typedef struct kmutex kmutex_t;
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#if defined(__MUTEX_PRIVATE)
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#define MUTEX_THREAD ((uintptr_t)-16L)
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#define MUTEX_BIT_SPIN 0x01
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#define MUTEX_BIT_WAITERS 0x02
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#if defined(LOCKDEBUG)
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#define MUTEX_BIT_NODEBUG 0x04 /* LOCKDEBUG disabled */
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#else
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#define MUTEX_BIT_NODEBUG 0x00 /* do nothing */
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#endif /* LOCKDEBUG */
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#define MUTEX_SPIN_IPL(mtx) ((mtx)->mtx_ipl)
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#define MUTEX_SPIN_OLDSPL(ci) ((ci)->ci_mtx_oldspl)
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void mutex_vector_enter(kmutex_t *);
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void mutex_vector_exit(kmutex_t *);
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void mutex_spin_retry(kmutex_t *);
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void mutex_wakeup(kmutex_t *);
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#endif /* __MUTEX_PRIVATE */
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#ifdef _KERNEL
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#include <sys/intr.h>
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#endif
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#include <machine/mutex.h>
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/*
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* Return true if no spin mutexes are held by the current CPU.
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*/
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#ifndef MUTEX_NO_SPIN_ACTIVE_P
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#define MUTEX_NO_SPIN_ACTIVE_P(ci) ((ci)->ci_mtx_count == 0)
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#endif
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#ifdef _KERNEL
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void mutex_init(kmutex_t *, kmutex_type_t, int);
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void mutex_destroy(kmutex_t *);
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void mutex_enter(kmutex_t *);
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void mutex_exit(kmutex_t *);
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void mutex_spin_enter(kmutex_t *);
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void mutex_spin_exit(kmutex_t *);
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int mutex_tryenter(kmutex_t *);
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int mutex_owned(kmutex_t *);
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lwp_t *mutex_owner(kmutex_t *);
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void mutex_obj_init(void);
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kmutex_t *mutex_obj_alloc(kmutex_type_t, int);
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void mutex_obj_hold(kmutex_t *);
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bool mutex_obj_free(kmutex_t *);
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#endif /* _KERNEL */
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#endif /* _SYS_MUTEX_H_ */
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