asynchronous I/O operations

NTDEV
1

Hai All,

I am implementing IRP_MJ_READ dispatch routine which marks the IRP as
pending and returns STATUS_PENDING and then process the IRP later. My
driver does not have any StartIO routine. How do I process and complete
the pending IRP.

So if I want to support asynchronous I/O operations in my driver is it
enough to return STATUS_PENDING after calling IoMarkIrpPending() for the
actual request and then complete the actual IRP(request) by
IoCompleteRequest(Irp,IO_NO_INCREMENT) in other thread. Does I need to do
anything else.

Any information would be helpful.

Thanx in advance.
Kedar…

2

Yeah that’s right.If you want to pass IRP down the stack,register a
completion routine for your IRP and then compete the IRP in your completion
routine

Regs,
Sai

From: kedar[SMTP:xxxxx@hotmail.com]
Reply To: NT Developers Interest List
Sent: Tuesday, May 28, 2002 4:39 PM
To: NT Developers Interest List
Subject: [ntdev] asynchronous I/O operations

Hai All,

I am implementing IRP_MJ_READ dispatch routine which marks the IRP as
pending and returns STATUS_PENDING and then process the IRP later. My
driver does not have any StartIO routine. How do I process and complete
the pending IRP.

So if I want to support asynchronous I/O operations in my driver is it
enough to return STATUS_PENDING after calling IoMarkIrpPending() for the
actual request and then complete the actual IRP(request) by
IoCompleteRequest(Irp,IO_NO_INCREMENT) in other thread. Does I need to do
anything else.

Any information would be helpful.

Thanx in advance.
Kedar…

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3

Before you call IoCompleteRequest, you probably want to set

Irp.Status = return code (such as STATUS_SUCCESS)
Irp.IoStatus.Information = number of bytes returned in output buffer

  • Dennis

Dennis Merrill
Embedded Systems Engineer
Thermo Electron Corporation
Spectroscopy Division

-----Original Message-----
From: kedar [mailto:xxxxx@hotmail.com]
Sent: Tuesday, May 28, 2002 6:09 AM
To: NT Developers Interest List
Subject: [ntdev] asynchronous I/O operations

Hai All,

I am implementing IRP_MJ_READ dispatch routine which marks the IRP as
pending and returns STATUS_PENDING and then process the IRP later. My
driver does not have any StartIO routine. How do I process and complete
the pending IRP.

So if I want to support asynchronous I/O operations in my driver is it
enough to return STATUS_PENDING after calling IoMarkIrpPending() for the
actual request and then complete the actual IRP(request) by
IoCompleteRequest(Irp,IO_NO_INCREMENT) in other thread. Does I need to do
anything else.

Any information would be helpful.

Thanx in advance.
Kedar…

You are currently subscribed to ntdev as: xxxxx@thermonicolet.com
To unsubscribe send a blank email to %%email.unsub%%