Reusing Framework Request Objects

To improve performance, framework-based drivers that create and send lots of nearly identical asynchronous requests to an I/O target can reuse request objects instead of creating a new request object for each request. A driver can reuse a request object after the request has been completed.

If a driver has created a request object by calling WdfRequestCreate or WdfRequestCreateFromIrp, it can reuse the request by calling WdfRequestReuse. A driver can also reuse request objects that it has received from the framework in its I/O queues, but it cannot change the IRP that the received request object contains.

If you are careful to avoid situations that cause the unsuccessful return values described in WdfRequestReuse, your driver can call WdfRequestReuse from within a CompletionRoutine callback function. (The CompletionRoutine callback function has a VOID return value and therefore cannot report errors.)

If your driver provides a CompletionRoutine callback function for a request object that it reuses, the driver must call WdfRequestSetCompletionRoutine after calling WdfRequestReuse.

 

 

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