MDL chaining

NTDEV
1

Does anyboy know how to perform MDL chaining ?

Apparently TDI has an interface in the kernel
“TdiCopyBufferToMdl” to copy to and from MDL chains.

The driver would be an NDIS intermediate driver or an
NDIS Miniport.

Alternatively does anyone know if it is possible to
setup a scatter/gather list with multiple Mdl’s in a
single Irp ?

The MDL structure has a next field for MDL chaining.

Thanks
-venkat

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2

Does anyboy know how to perform MDL chaining ?

Apparently TDI has an interface in the kernel
“TdiCopyBufferToMdl” to copy to and from MDL chains.

The driver would be an NDIS intermediate driver or an
NDIS Miniport.

Alternatively does anyone know if it is possible to
setup a scatter/gather list with multiple Mdl’s in a
single Irp ?

The MDL structure has a next field for MDL chaining.

Thanks
-venkat

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3

Just build a chain of MDLs using the MDL Next field.

Here is an example of building a MDL chain:

(pSession->m_pPatternHeaderMdl)->Next = pSession->m_pPatternDataMdl;
(pSession->m_pPatternDataMdl)->Next = NULL; // IMPORTANT!!!

Then the first MDL of the chain is passed to TDI (e.g., send datagram…).

xyz( pSession->m_pPatternHeaderMdl, …);

Of course, all MDLs must be probed and locked.

That’s about it…

Regards,

Thomas F. Divine

PCAUSA - Toolkits & Resources For Network Software Developers
NDIS Protocol - NDIS Intermediate - TDI Client
http: - http:

----- Original Message -----
From: “vi -”
To: “NT Developers Interest List”
Sent: Sunday, June 24, 2001 12:58 AM
Subject: [ntdev] MDL chaining

> Does anyboy know how to perform MDL chaining ?
>
> Apparently TDI has an interface in the kernel
> “TdiCopyBufferToMdl” to copy to and from MDL chains.
>
> The driver would be an NDIS intermediate driver or an
> NDIS Miniport.
>
> Alternatively does anyone know if it is possible to
> setup a scatter/gather list with multiple Mdl’s in a
> single Irp ?
>
> The MDL structure has a next field for MDL chaining.
>
> Thanks
> -venkat
>
>
>
> __________________________________________________
> Do You Yahoo!?
> Get personalized email addresses from Yahoo! Mail
> http://personal.mail.yahoo.com/
>
> —
> You are currently subscribed to ntdev as: xxxxx@pcausa.com
> To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com

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4

> Does anyboy know how to perform MDL chaining ?

Just use the Next field in the MDL.

Max

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