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     if( state == kIOLockStateLocked)
  53         IOLockLock( lock);
  54 }
  55
  56 struct _IORecursiveLock {
  57     mutex_t  *  mutex;
  58     thread_t    thread;
  59     UInt32      count;
  60 };
  61
  62 IORecursiveLock * IORecursiveLockAlloc( void )
  63 {
  64     _IORecursiveLock * lock;
  65
  66     lock = IONew( _IORecursiveLock, 1);
  67     if( !lock)
  68         return( 0 );
  69
  70     lock->mutex = mutex_alloc(ETAP_IO_AHA);
  71     if( lock->mutex) {
  72         lock->thread = 0;
  73         lock->count  = 0;
  74     } else {
  75         IODelete( lock, _IORecursiveLock, 1);
  76         lock = 0;
  77     }
  78
  79     return( (IORecursiveLock *) lock );
  80 }
  81
  82 void IORecursiveLockFree( IORecursiveLock * _lock )
  83 {
  84     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
  85
  86     mutex_free( lock->mutex );
  87     IODelete( lock, _IORecursiveLock, 1);
  88 }
  89
  90 void IORecursiveLockLock( IORecursiveLock * _lock)
  91 {
  92     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
  93
  94     if( lock->thread == IOThreadSelf())
  95         lock->count++;
  96     else {
  97         mutex_lock( lock->mutex );
  98         assert( lock->thread == 0 );
  99         assert( lock->count == 0 );
 100         lock->thread = IOThreadSelf();
 101         lock->count = 1;
 102     }
 103 }
 104
 105 boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
 106 {
 107     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 108
 109     if( lock->thread == IOThreadSelf()) {
 110         lock->count++;
 111         return( true );
 112     } else {
 113         if( mutex_try( lock->mutex )) {
 114             assert( lock->thread == 0 );
 115             assert( lock->count == 0 );
 116             lock->thread = IOThreadSelf();
 117             lock->count = 1;
 118             return( true );
 119         }
 120     }
 121     return( false );
 122 }
 123
 124 void IORecursiveLockUnlock( IORecursiveLock * _lock)
 125 {
 126     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 127
 128     assert( lock->thread == IOThreadSelf() );
 129
 130     if( 0 == (--lock->count)) {
 131         lock->thread = 0;
 132         mutex_unlock( lock->mutex );
 133     }
 134 }
 135
 136 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
 137 {
 138     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 139
 140     return( lock->thread == IOThreadSelf());
 141 }
 142
 143 int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
 144 {
 145     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 146     UInt32 count = lock->count;
 147     int res;
 148
 149     assert(lock->thread == IOThreadSelf());
 150     assert(lock->count == 1 || interType == THREAD_UNINT);
 151
 152     assert_wait((event_t) event, (int) interType);
 153     lock->count = 0;
 154     lock->thread = 0;
 155     mutex_unlock(lock->mutex);
 156
 157     res = thread_block(0);
 158
 159     // Must re-establish the recursive lock no matter why we woke up
 160     // otherwise we would potentially leave the return path corrupted.
 161     mutex_lock(lock->mutex);
 162     assert(lock->thread == 0);
 163     assert(lock->count == 0);
 164     lock->thread = IOThreadSelf();
 165     lock->count = count;
 166
 167     return res;
 168 }
 169
 170 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
 171 {
 172     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
 173 }
 174
 175 /*
 176  * Complex (read/write) lock operations
 177  */
 178
 179 IORWLock * IORWLockAlloc( void )
 180 {
 181     IORWLock * lock;
 182
 183     lock = lock_alloc( true, ETAP_IO_AHA, ETAP_IO_AHA);
 184
 185     return( lock);
 186 }
 187
 188 void    IORWLockFree( IORWLock * lock)
 189 {
 190     lock_free( lock );
 191 }
 192
 193
 194 /*
 195  * Spin locks
 196  */
 197
 198 IOSimpleLock * IOSimpleLockAlloc( void )
 199 {
 200     IOSimpleLock *      lock;
 201
 202     lock = (IOSimpleLock *) IOMalloc( sizeof(IOSimpleLock));
 203     if( lock)
 204         IOSimpleLockInit( lock );
 205
 206     return( lock );
 207 }
 208
 209 void IOSimpleLockInit( IOSimpleLock * lock)
 210 {
 211     simple_lock_init( (simple_lock_t) lock, ETAP_IO_AHA );
 212 }
 213
 214 void IOSimpleLockFree( IOSimpleLock * lock )
 215 {
 216     IOFree( lock, sizeof(IOSimpleLock));
 217 }
 218
 219 } /* extern "C" */
 220
 221