Question about Irp usage in a NT layered driver

NTDEV
1

In an IRP that is allocated by a Kernel Driver to communicate with a lower
level driver, do we need to set the UserIosb,
Tail.Overlay.Thread, and RequestorMode fields? If we do, do bad things
happen?

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2

I never have. Use one of the IoBuild…Irp functions and handle the stack
location for the task at hand.

Gary

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ken Davenport
Sent: Saturday, December 01, 2001 12:11 AM
To: NT Developers Interest List
Subject: [ntdev] Question about Irp usage in a NT layered driver

In an IRP that is allocated by a Kernel Driver to communicate with a lower
level driver, do we need to set the UserIosb,
Tail.Overlay.Thread, and RequestorMode fields? If we do, do bad things
happen?

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3

No need in Tail.Overlay.Thread or UserIosb if you will not unwind the IRP to completion and will use STATUS_MORE_PROCESSING_REQUIRED
and IoFreeIrp instead.
If you do not use Irp->UserBuffer - then no need in using Irp->RequestorMode too.

But if you call things like FSCTLs which require UserBuffer - then set RequestorMode to the kind of memory space to which UserBuffer
points.

Max

----- Original Message -----
From: “Ken Davenport”
To: “NT Developers Interest List”
Sent: Saturday, December 01, 2001 12:10 AM
Subject: [ntdev] Question about Irp usage in a NT layered driver

> In an IRP that is allocated by a Kernel Driver to communicate with a lower
> level driver, do we need to set the UserIosb,
> Tail.Overlay.Thread, and RequestorMode fields? If we do, do bad things
> happen?
>
>
> —
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> To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com
>

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