reactos/drivers/network/tcpip/recmutex/recmutex.c

   1 #include <ntddk.h>
   2 #include "recmutex.h"
   3
   4 VOID RecursiveMutexInit( PRECURSIVE_MUTEX RecMutex ) {
   5     RtlZeroMemory( RecMutex, sizeof(*RecMutex) );
   6     ExInitializeFastMutex( &RecMutex->Mutex );
   7     KeInitializeEvent( &RecMutex->StateLockedEvent,
   8         NotificationEvent, FALSE );
   9 }
  10
  11 /* NOTE: When we leave, the FAST_MUTEX must have been released.  The result
  12 * is that we always exit in the same irql as entering */
  13 VOID RecursiveMutexEnter( PRECURSIVE_MUTEX RecMutex ) {
  14     NTSTATUS Status = STATUS_SUCCESS;
  15     PVOID CurrentThread = KeGetCurrentThread();
  16
  17     ASSERT(RecMutex);
  18     ASSERT(KeGetCurrentIrql() <= APC_LEVEL);
  19
  20     /* Wait for the previous user to unlock the RecMutex state.  There might be
  21     * multiple waiters waiting to change the state.  We need to check each
  22     * time we get the event whether somebody still has the state locked */
  23
  24     ExAcquireFastMutex( &RecMutex->Mutex );
  25
  26     if( CurrentThread == RecMutex->CurrentThread ) {
  27             RecMutex->LockCount++;
  28             ExReleaseFastMutex( &RecMutex->Mutex );
  29             return;
  30     }
  31
  32     while( RecMutex->LockCount != 0 ) {
  33          ExReleaseFastMutex( &RecMutex->Mutex );
  34          Status = KeWaitForSingleObject( &RecMutex->StateLockedEvent,
  35              UserRequest,
  36              KernelMode,
  37              FALSE,
  38              NULL );
  39          ExAcquireFastMutex( &RecMutex->Mutex );
  40     }
  41     RecMutex->CurrentThread = CurrentThread;
  42     RecMutex->LockCount++;
  43     ExReleaseFastMutex( &RecMutex->Mutex );
  44 }
  45
  46 VOID RecursiveMutexLeave( PRECURSIVE_MUTEX RecMutex ) {
  47     ASSERT(RecMutex);
  48
  49     ExAcquireFastMutex( &RecMutex->Mutex );
  50
  51     ASSERT(RecMutex->LockCount > 0);
  52     RecMutex->LockCount--;
  53
  54     if( !RecMutex->LockCount ) {
  55         KePulseEvent( &RecMutex->StateLockedEvent, IO_NETWORK_INCREMENT,
  56             FALSE );
  57     }
  58
  59     ExReleaseFastMutex( &RecMutex->Mutex );
  60 }
  61