RxCeAllocateIrpWithMDL function

RxCeAllocateIrpWithMDL allocates an IRP and associates it with an existing memory descriptor list.


PIRP RxCeAllocateIrpWithMDL(
  _In_ CCHAR   StackSize,
  _In_ BOOLEAN ChargeQuota,
  _In_ PMDL    Buffer


StackSize [in]

The stack size to allocate for the IRP.

ChargeQuota [in]

This parameter should be set to FALSE by intermediate drivers. This can be set to TRUE only by highest-level drivers that are called in the context of the thread that originates the I/O request for which the driver is allocating another IRP.

Buffer [in]

A pointer to the buffer that contains the memory descriptor list to be associated with this IRP.

Return value

RxCeAllocateIrpWithMDL returns a pointer to the IRP on success or a NULL pointer on error.


The goal of RxCeAllocateIrpWithMDL is to allow easier debugging of IRPs that are issued to other components and then stall. IRPs issued using RxCeAllocateIrpWithMDL are queued to a global list of IRPs maintained by RDBSS. Thus, when an RX_CONTEXT is waiting for a send completion, it is possible to walk the global list to find the IRP that is waiting in the transport.

An IRP allocated with an associated memory descriptor list allocated with RxCeAllocateIrpWithMDL should be freed when the IRP is completed using RxCeFreeIrp.

IoAllocateIrp automatically initializes the IRP's members and inserts the IRP into a global list of IRPs maintained by RDBSS. If memory for the MDL to be associated with the IRP cannot be allocated, then the IRP that was created is freed and RxCeAllocateIrpWithMDL returns a NULL pointer indicating failure.


Target platform



The RxCeAllocateIrpWithMDL routine is only available on Windows XP.


Rxce.h (include Rxce.h)



See also




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