IoCompleteRequest

VOID
IoCompleteRequest(
IN PIRP Irp,
IN CCHAR PriorityBoost
);

IoCompleteRequest indicates the caller has completed all processing for a given I/O request and is returning the given IRP to the I/O Manager.

Parameters

Irp: Points to the IRP to be completed.
PriorityBoost: Specifies a system-defined constant by which to increment the runtime priority of the original thread that requested the operation. This value is IO_NO_INCREMENT if the original thread requested an operation the driver could complete quickly (so the requesting thread is not compensated for its assumed wait on I/O) or if the IRP is completed with an error. Otherwise, the set of PriorityBoost constants are device-type-specific. See ntddk.h for these constants.

Comments

When a driver has finished all processing for a given IRP, it calls IoCompleteRequest. The I/O Manager checks the IRP to determine whether any higher-level drivers have set up an IoCompletion routine for the IRP. If so, each IoCompletion routine is called, in turn, until every layered driver in the chain has completed the IRP.

When all drivers have completed a given IRP, the I/O Manger returns status to the original requestor of the operation. Note that a higher-level driver that sets up a driver-created IRP must supply an IoCompletion routine to release the IRP it created.

Callers of IoCompleteRequest must be running at IRQL <= DISPATCH_LEVEL.