reactos/doc/irp cancel boilerplate.c

   1
   2
   3 /*
   4 Boiler plate for irp cancelation, for irp queues you manage yourself
   5 -Gunnar
   6 */
   7
   8
   9
  10 CancelRoutine(
  11    DEV_OBJ Dev,
  12    Irp
  13    )
  14 {
  15    //don't need this since we have our own sync. protecting irp cancellation
  16    IoReleaseCancelSpinLock(Irp->CancelIrql);
  17
  18    theLock = Irp->Tail.Overlay.DriverContext[3];
  19
  20    Lock(theLock);
  21    RemoveEntryList(&Irp->Tail.Overlay.ListEntry);
  22    Unlock(theLock);
  23
  24    Irp->IoStatus.Status = STATUS_CANCELLED;
  25    Irp->IoStatus.Information = 0;
  26
  27    IoCompleteRequest(Irp, IO_NO_INCREMENT);
  28
  29 }
  30
  31
  32 QUEUE_BOLIERPLATE
  33 {
  34    Lock(theLock);
  35
  36    Irp->Tail.Overlay.DriverContext[3] = &theLock;
  37
  38    IoSetCancelRoutine(Irp, CancelRoutine);
  39    if (Irp->Cancel && IoSetCancelRoutine(Irp, NULL))
  40    {
  41       // IRP has already been cancelled (before we got to queue it),
  42       // but we got to remove the cancel routine before the canceler could,
  43       // so complete irp ourself
  44
  45       Unlock(theLock);
  46
  47       Irp->IoStatus.Status = STATUS_CANCELLED;
  48       Irp->IoStatus.Information = 0;
  49       IoCompleteRequest(Irp, IO_NO_INCREMENT);
  50
  51       return FALSE;
  52    }
  53
  54    //else were ok
  55
  56
  57    Irp->IoStatus.Status = STATUS_PENDING;
  58    IoMarkIrpPending(Irp);
  59
  60    InsertTailList(Queue);
  61
  62    Unlock(theLock);
  63
  64 }
  65
  66
  67 DEQUEUE_BOILERPLATE
  68 {
  69    Lock(theLock);
  70
  71    Irp = RemoveHeadList(Queue);
  72
  73    if (!IoSetCancelRoutine(Irp, NULL))
  74    {
  75       /*
  76       Cancel routine WILL be called after we release the spinlock. It will try to remove
  77       the irp from the list and cancel/complete this irp. Since we allready removed it,
  78       make its ListEntry point to itself.
  79       */
  80
  81       InitializeListHead(&Irp->Tail.Overlay.ListEntry);
  82    }
  83
  84
  85    /*
  86    Cancel routine will NOT be called, canceled or not.
  87    The Irp might have been canceled (Irp->Cancel flag set) but we don't care,
  88    since we are to complete this Irp now anyways.
  89    */
  90
  91    Unlock(theLock);
  92
  93    Irp->IoStatus.Status = STATUS_SUCCESS;
  94    Irp->IoStatus.Information = 0;
  95    IoCompleteRequest(Irp, IO_NO_INCREMENT);
  96
  97 }
  98
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