FreeBSD/Linux Kernel Cross Reference
sys/iokit/Kernel/IOLocks.cpp

     /*
      * Copyright (c) 1998-2007 Apple Inc. All rights reserved.
      *
      * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
      * Version 2.0 (the 'License'). You may not use this file except in
      * compliance with the License. The rights granted to you under the License
     * may not be used to create, or enable the creation or redistribution of,
     * unlawful or unlicensed copies of an Apple operating system, or to
     * circumvent, violate, or enable the circumvention or violation of, any
     * terms of an Apple operating system software license agreement.
     * 
     * Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
     */
    /*
     * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
     *
     * HISTORY
     *
     */
    
    
    #define IOLOCKS_CPP     1
    
    #include <IOKit/system.h>
    
    #include <IOKit/IOReturn.h>
    #include <IOKit/IOLib.h> 
    #include <IOKit/assert.h>
    
    #include <IOKit/IOLocksPrivate.h>
    
    extern "C" {
    #include <kern/locks.h>
    
    void    IOLockInitWithState( IOLock * lock, IOLockState state)
    {
        if( state == kIOLockStateLocked)
            lck_mtx_lock( lock);
    }
    
    IOLock * IOLockAlloc( void )
    {
        return( lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL) );
    }
    
    void    IOLockFree( IOLock * lock)
    {
        lck_mtx_free( lock, IOLockGroup);
    }
    
    lck_mtx_t * IOLockGetMachLock( IOLock * lock)
    {
        return( (lck_mtx_t *)lock);
    }
    
    int     IOLockSleep( IOLock * lock, void *event, UInt32 interType)
    {
        return (int) lck_mtx_sleep(lock, LCK_SLEEP_DEFAULT, (event_t) event, (wait_interrupt_t) interType);
    }
    
    int     IOLockSleepDeadline( IOLock * lock, void *event,
                                    AbsoluteTime deadline, UInt32 interType)
    {
        return (int) lck_mtx_sleep_deadline(lock, LCK_SLEEP_DEFAULT, (event_t) event,
                                            (wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
    }
    
    void    IOLockWakeup(IOLock * lock, void *event, bool oneThread)
    {   
            thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
    }   
    
    
    struct _IORecursiveLock {
            lck_mtx_t       *mutex;
            lck_grp_t       *group;
            thread_t        thread;
            UInt32          count;
    };
    
    IORecursiveLock * IORecursiveLockAllocWithLockGroup( lck_grp_t * lockGroup )
    {
        _IORecursiveLock * lock;
    
        if( lockGroup == 0 )
           return( 0 );
   
       lock = IONew( _IORecursiveLock, 1 );
       if( !lock )
           return( 0 );
   
       lock->mutex = lck_mtx_alloc_init( lockGroup, LCK_ATTR_NULL );
       if( lock->mutex ) {
                   lock->group = lockGroup;
           lock->thread = 0;
           lock->count  = 0;
       } else {
           IODelete( lock, _IORecursiveLock, 1 );
           lock = 0;
       }
   
       return( (IORecursiveLock *) lock );
   }
   
   
   IORecursiveLock * IORecursiveLockAlloc( void )
   {
       return IORecursiveLockAllocWithLockGroup( IOLockGroup );
   }
   
   void IORecursiveLockFree( IORecursiveLock * _lock )
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
           
       lck_mtx_free( lock->mutex, lock->group );
       IODelete( lock, _IORecursiveLock, 1 );
   }
   
   lck_mtx_t * IORecursiveLockGetMachLock( IORecursiveLock * lock )
   {
       return( lock->mutex );
   }
   
   void IORecursiveLockLock( IORecursiveLock * _lock)
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
   
       if( lock->thread == IOThreadSelf())
           lock->count++;
       else {
           lck_mtx_lock( lock->mutex );
           assert( lock->thread == 0 );
           assert( lock->count == 0 );
           lock->thread = IOThreadSelf();
           lock->count = 1;
       }
   }
   
   boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
   
       if( lock->thread == IOThreadSelf()) {
           lock->count++;
           return( true );
       } else {
           if( lck_mtx_try_lock( lock->mutex )) {
               assert( lock->thread == 0 );
               assert( lock->count == 0 );
               lock->thread = IOThreadSelf();
               lock->count = 1;
               return( true );
           }
       }
       return( false );
   }
   
   void IORecursiveLockUnlock( IORecursiveLock * _lock)
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
   
       assert( lock->thread == IOThreadSelf() );
   
       if( 0 == (--lock->count)) {
           lock->thread = 0;
           lck_mtx_unlock( lock->mutex );
       }
   }
   
   boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
   
       return( lock->thread == IOThreadSelf());
   }
   
   int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
   {
       _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
       UInt32 count = lock->count;
       int res;
   
       assert(lock->thread == IOThreadSelf());
       assert(lock->count == 1 || interType == THREAD_UNINT);
       
       lock->count = 0;
       lock->thread = 0;
       res = lck_mtx_sleep(lock->mutex, LCK_SLEEP_DEFAULT, (event_t) event, (wait_interrupt_t) interType);
   
       // Must re-establish the recursive lock no matter why we woke up
       // otherwise we would potentially leave the return path corrupted.
       assert(lock->thread == 0);
       assert(lock->count == 0);
       lock->thread = IOThreadSelf();
       lock->count = count;
       return res;
   }
   
   void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
   {
       thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
   }
   
   /*
    * Complex (read/write) lock operations
    */
   
   IORWLock * IORWLockAlloc( void )
   {
       return(  lck_rw_alloc_init(IOLockGroup, LCK_ATTR_NULL)  );
   }
   
   void    IORWLockFree( IORWLock * lock)
   {
       lck_rw_free( lock, IOLockGroup);
   }
   
   lck_rw_t * IORWLockGetMachLock( IORWLock * lock)
   {
       return( (lck_rw_t *)lock);
   }
   
   
   /*
    * Spin locks
    */
   
   IOSimpleLock * IOSimpleLockAlloc( void )
   {
       return( lck_spin_alloc_init( IOLockGroup, LCK_ATTR_NULL) );
   }
   
   void IOSimpleLockInit( IOSimpleLock * lock)
   {
       lck_spin_init( lock, IOLockGroup, LCK_ATTR_NULL);
   }
   
   void IOSimpleLockFree( IOSimpleLock * lock )
   {
       lck_spin_free( lock, IOLockGroup);
   }
   
   lck_spin_t * IOSimpleLockGetMachLock( IOSimpleLock * lock)
   {
       return( (lck_spin_t *)lock);
   }
   
   } /* extern "C" */
   
   

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