iokit/Kernel/IOLocks.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  24  *
  25  * HISTORY
  26  *
  27  */
  28
  29
  30 #include <IOKit/system.h>
  31
  32 #include <IOKit/IOReturn.h>
  33 #include <IOKit/IOLib.h>
  34 #include <IOKit/assert.h>
  35
  36 extern "C" {
  37 #include <kern/simple_lock.h>
  38 #include <machine/machine_routines.h>
  39
  40 IOLock * IOLockAlloc( void )
  41 {
  42     return( mutex_alloc(ETAP_IO_AHA) );
  43 }
  44
  45 void    IOLockFree( IOLock * lock)
  46 {
  47     mutex_free( lock );
  48 }
  49
  50 void    IOLockInitWithState( IOLock * lock, IOLockState state)
  51 {
  52     mutex_init( lock, ETAP_IO_AHA);
  53
  54     if( state == kIOLockStateLocked)
  55         IOLockLock( lock);
  56 }
  57
  58 struct _IORecursiveLock {
  59     mutex_t  *  mutex;
  60     thread_t    thread;
  61     UInt32      count;
  62 };
  63
  64 IORecursiveLock * IORecursiveLockAlloc( void )
  65 {
  66     _IORecursiveLock * lock;
  67
  68     lock = IONew( _IORecursiveLock, 1);
  69     if( !lock)
  70         return( 0 );
  71
  72     lock->mutex = mutex_alloc(ETAP_IO_AHA);
  73     if( lock->mutex) {
  74         lock->thread = 0;
  75         lock->count  = 0;
  76     } else {
  77         IODelete( lock, _IORecursiveLock, 1);
  78         lock = 0;
  79     }
  80
  81     return( (IORecursiveLock *) lock );
  82 }
  83
  84 void IORecursiveLockFree( IORecursiveLock * _lock )
  85 {
  86     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
  87
  88     mutex_free( lock->mutex );
  89     IODelete( lock, _IORecursiveLock, 1);
  90 }
  91
  92 void IORecursiveLockLock( IORecursiveLock * _lock)
  93 {
  94     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
  95
  96     if( lock->thread == IOThreadSelf())
  97         lock->count++;
  98     else {
  99         _mutex_lock( lock->mutex );
 100         assert( lock->thread == 0 );
 101         assert( lock->count == 0 );
 102         lock->thread = IOThreadSelf();
 103         lock->count = 1;
 104     }
 105 }
 106
 107 boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
 108 {
 109     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 110
 111     if( lock->thread == IOThreadSelf()) {
 112         lock->count++;
 113         return( true );
 114     } else {
 115         if( _mutex_try( lock->mutex )) {
 116             assert( lock->thread == 0 );
 117             assert( lock->count == 0 );
 118             lock->thread = IOThreadSelf();
 119             lock->count = 1;
 120             return( true );
 121         }
 122     }
 123     return( false );
 124 }
 125
 126 void IORecursiveLockUnlock( IORecursiveLock * _lock)
 127 {
 128     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 129
 130     assert( lock->thread == IOThreadSelf() );
 131
 132     if( 0 == (--lock->count)) {
 133         lock->thread = 0;
 134         mutex_unlock( lock->mutex );
 135     }
 136 }
 137
 138 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
 139 {
 140     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 141
 142     return( lock->thread == IOThreadSelf());
 143 }
 144
 145 int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
 146 {
 147     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 148     UInt32 count = lock->count;
 149     int res;
 150
 151     assert(lock->thread == IOThreadSelf());
 152     assert(lock->count == 1 || interType == THREAD_UNINT);
 153
 154     assert_wait((event_t) event, (int) interType);
 155     lock->count = 0;
 156     lock->thread = 0;
 157     mutex_unlock(lock->mutex);
 158
 159     res = thread_block(0);
 160
 161     if (THREAD_AWAKENED == res) {
 162         _mutex_lock(lock->mutex);
 163         assert(lock->thread == 0);
 164         assert(lock->count == 0);
 165         lock->thread = IOThreadSelf();
 166         lock->count = count;
 167     }
 168
 169     return res;
 170 }
 171
 172 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
 173 {
 174     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
 175 }
 176
 177 /*
 178  * Complex (read/write) lock operations
 179  */
 180
 181 IORWLock * IORWLockAlloc( void )
 182 {
 183     IORWLock * lock;
 184
 185     lock = lock_alloc( true, ETAP_IO_AHA, ETAP_IO_AHA);
 186
 187     return( lock);
 188 }
 189
 190 void    IORWLockFree( IORWLock * lock)
 191 {
 192     lock_free( lock );
 193 }
 194
 195
 196 /*
 197  * Spin locks
 198  */
 199
 200 IOSimpleLock * IOSimpleLockAlloc( void )
 201 {
 202     IOSimpleLock *      lock;
 203
 204     lock = (IOSimpleLock *) IOMalloc( sizeof(IOSimpleLock));
 205     if( lock)
 206         IOSimpleLockInit( lock );
 207
 208     return( lock );
 209 }
 210
 211 void IOSimpleLockInit( IOSimpleLock * lock)
 212 {
 213     simple_lock_init( (simple_lock_t) lock, ETAP_IO_AHA );
 214 }
 215
 216 void IOSimpleLockFree( IOSimpleLock * lock )
 217 {
 218     IOFree( lock, sizeof(IOSimpleLock));
 219 }
 220
 221 } /* extern "C" */
 222
 223