reactos/ntoskrnl/io/iomgr/iotimer.c

   1 /*
   2  * PROJECT:         ReactOS Kernel
   3  * LICENSE:         GPL - See COPYING in the top level directory
   4  * FILE:            ntoskrnl/io/iocomp.c
   5  * PURPOSE:         I/O Wrappers for Executive Timers
   6  * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
   7  */
   8
   9 /* INCLUDES *****************************************************************/
  10
  11 #include <ntoskrnl.h>
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 /* GLOBALS *******************************************************************/
  16
  17 /* Timer Database */
  18 KSPIN_LOCK IopTimerLock;
  19 LIST_ENTRY IopTimerQueueHead;
  20
  21 /* Timer Firing */
  22 KDPC IopTimerDpc;
  23 KTIMER IopTimer;
  24
  25 /* Keep count of how many timers we have */
  26 ULONG IopTimerCount = 0;
  27
  28 /* PRIVATE FUNCTIONS *********************************************************/
  29
  30 VOID
  31 NTAPI
  32 IopTimerDispatch(IN PKDPC Dpc,
  33                  IN PVOID DeferredContext,
  34                  IN PVOID SystemArgument1,
  35                  IN PVOID SystemArgument2)
  36 {
  37     KIRQL OldIrql;
  38     PLIST_ENTRY TimerEntry;
  39     PIO_TIMER Timer;
  40     ULONG i;
  41
  42     /* Check if any Timers are actualyl enabled as of now */
  43     if (IopTimerCount)
  44     {
  45         /* Lock the Timers */
  46         KeAcquireSpinLock(&IopTimerLock, &OldIrql);
  47
  48         /* Call the Timer Routine of each enabled Timer */
  49         for (TimerEntry = IopTimerQueueHead.Flink, i = IopTimerCount;
  50             (TimerEntry != &IopTimerQueueHead) && i;
  51             TimerEntry = TimerEntry->Flink)
  52         {
  53             /* Get the timer and check if it's enabled */
  54             Timer = CONTAINING_RECORD(TimerEntry, IO_TIMER, IoTimerList);
  55             if (Timer->TimerEnabled)
  56             {
  57                 /* Call the timer routine */
  58                 Timer->TimerRoutine(Timer->DeviceObject, Timer->Context);
  59                 i--;
  60             }
  61         }
  62
  63         /* Unlock the Timers */
  64         KeReleaseSpinLock(&IopTimerLock, OldIrql);
  65     }
  66 }
  67
  68 VOID
  69 NTAPI
  70 IopRemoveTimerFromTimerList(IN PIO_TIMER Timer)
  71 {
  72     KIRQL OldIrql;
  73
  74     /* Lock Timers */
  75     KeAcquireSpinLock(&IopTimerLock, &OldIrql);
  76
  77     /* Remove Timer from the List and Drop the Timer Count if Enabled */
  78     RemoveEntryList(&Timer->IoTimerList);
  79     if (Timer->TimerEnabled) IopTimerCount--;
  80
  81     /* Unlock the Timers */
  82     KeReleaseSpinLock(&IopTimerLock, OldIrql);
  83 }
  84
  85 /* PUBLIC FUNCTIONS **********************************************************/
  86
  87 /*
  88  * @implemented
  89  */
  90 NTSTATUS
  91 NTAPI
  92 IoInitializeTimer(IN PDEVICE_OBJECT DeviceObject,
  93                   IN PIO_TIMER_ROUTINE TimerRoutine,
  94                   IN PVOID Context)
  95 {
  96     PIO_TIMER IoTimer = DeviceObject->Timer;
  97     PAGED_CODE();
  98
  99     /* Check if we don't have a timer yet */
 100     if (!IoTimer)
 101     {
 102         /* Allocate Timer */
 103         IoTimer = ExAllocatePoolWithTag(NonPagedPool,
 104                                         sizeof(IO_TIMER),
 105                                         TAG_IO_TIMER);
 106         if (!IoTimer) return STATUS_INSUFFICIENT_RESOURCES;
 107
 108         /* Set up the Timer Structure */
 109         RtlZeroMemory(IoTimer, sizeof(IO_TIMER));
 110         IoTimer->Type = IO_TYPE_TIMER;
 111         IoTimer->DeviceObject = DeviceObject;
 112         DeviceObject->Timer = IoTimer;
 113     }
 114
 115     /* Setup the timer routine and context */
 116     IoTimer->TimerRoutine = TimerRoutine;
 117     IoTimer->Context = Context;
 118
 119     /* Add it to the Timer List */
 120     ExInterlockedInsertTailList(&IopTimerQueueHead,
 121                                 &IoTimer->IoTimerList,
 122                                 &IopTimerLock);
 123
 124     /* Return Success */
 125     return STATUS_SUCCESS;
 126 }
 127
 128 /*
 129  * @implemented
 130  */
 131 VOID
 132 NTAPI
 133 IoStartTimer(IN PDEVICE_OBJECT DeviceObject)
 134 {
 135     KIRQL OldIrql;
 136     PIO_TIMER IoTimer = DeviceObject->Timer;
 137
 138     /* Make sure the device isn't unloading */
 139     if (!(((PEXTENDED_DEVOBJ_EXTENSION)(DeviceObject->DeviceObjectExtension))->
 140             ExtensionFlags & (DOE_UNLOAD_PENDING |
 141                               DOE_DELETE_PENDING |
 142                               DOE_REMOVE_PENDING |
 143                               DOE_REMOVE_PROCESSED)))
 144     {
 145         /* Lock Timers */
 146         KeAcquireSpinLock(&IopTimerLock, &OldIrql);
 147
 148         /* Check if the timer isn't already enabled */
 149         if (!IoTimer->TimerEnabled)
 150         {
 151             /* Enable it and increase the timer count */
 152             IoTimer->TimerEnabled = TRUE;
 153             IopTimerCount++;
 154         }
 155
 156         /* Unlock Timers */
 157         KeReleaseSpinLock(&IopTimerLock, OldIrql);
 158     }
 159 }
 160
 161 /*
 162  * @implemented
 163  */
 164 VOID
 165 NTAPI
 166 IoStopTimer(PDEVICE_OBJECT DeviceObject)
 167 {
 168     KIRQL OldIrql;
 169     PIO_TIMER IoTimer = DeviceObject->Timer;
 170
 171     /* Lock Timers */
 172     KeAcquireSpinLock(&IopTimerLock, &OldIrql);
 173
 174     /* Check if the timer is enabled */
 175     if (IoTimer->TimerEnabled)
 176     {
 177         /* Disable it and decrease the timer count */
 178         IoTimer->TimerEnabled = FALSE;
 179         IopTimerCount--;
 180     }
 181
 182     /* Unlock Timers */
 183     KeReleaseSpinLock(&IopTimerLock, OldIrql);
 184 }
 185
 186 /* EOF */