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Annotation of XNU/iokit/Kernel/IOLocks.cpp, revision 1.1

1.1     ! root        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 IORecursiveLockTry( 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: /*
        !           146:  * Complex (read/write) lock operations
        !           147:  */
        !           148: 
        !           149: IORWLock * IORWLockAlloc( void )
        !           150: {
        !           151:     IORWLock * lock;
        !           152: 
        !           153:     lock = lock_alloc( true, ETAP_IO_AHA, ETAP_IO_AHA);
        !           154: 
        !           155:     return( lock);
        !           156: }
        !           157: 
        !           158: void   IORWLockFree( IORWLock * lock)
        !           159: {
        !           160:     lock_free( lock );
        !           161: }
        !           162: 
        !           163: 
        !           164: /*
        !           165:  * Spin locks
        !           166:  */
        !           167: 
        !           168: IOSimpleLock * IOSimpleLockAlloc( void )
        !           169: {
        !           170:     IOSimpleLock *     lock;
        !           171: 
        !           172:     lock = (IOSimpleLock *) IOMalloc( sizeof(IOSimpleLock));
        !           173:     if( lock)
        !           174:        IOSimpleLockInit( lock );
        !           175: 
        !           176:     return( lock );
        !           177: }
        !           178: 
        !           179: void IOSimpleLockInit( IOSimpleLock * lock)
        !           180: {
        !           181:     simple_lock_init( (simple_lock_t) lock, ETAP_IO_AHA );
        !           182: }
        !           183: 
        !           184: void IOSimpleLockFree( IOSimpleLock * lock )
        !           185: {
        !           186:     IOFree( lock, sizeof(IOSimpleLock));
        !           187: }
        !           188: 
        !           189: } /* extern "C" */
        !           190: 
        !           191: 

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