NDIS coalescing buffers when building sg list?

NTDEV
1

When I get a packet via my sendpacket routine, the mdls (for a UDP DHCP
request) are:
mdl[0] va = 82046040, length = 14
mdl[1] va = 82051040, length = 20
mdl[2] va = 82054060, length = 8
mdl[3] va = 823289C0, length = 300

which I assume correspond to the Ethernet header, IP header, UDP header,
and data respectively.

But when I look at the scatter gather structure, there is a single 342
byte entry.

Would I be correct in assuming that NDIS has copied all the data into a
single page and then used that in the sg list? I can’t think of any
other explanation…

Thanks

James

2

Disregard. I made a mistake in my DMA_ADAPTER that was incorrectly
producing the sg list.

James

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:bounce-352461-
xxxxx@lists.osr.com] On Behalf Of James Harper
Sent: Monday, 26 January 2009 12:44
To: Windows System Software Devs Interest List
Subject: [ntdev] NDIS coalescing buffers when building sg list?

When I get a packet via my sendpacket routine, the mdls (for a UDP
DHCP
request) are:
mdl[0] va = 82046040, length = 14
mdl[1] va = 82051040, length = 20
mdl[2] va = 82054060, length = 8
mdl[3] va = 823289C0, length = 300

which I assume correspond to the Ethernet header, IP header, UDP
header,
and data respectively.

But when I look at the scatter gather structure, there is a single 342
byte entry.

Would I be correct in assuming that NDIS has copied all the data into
a
single page and then used that in the sg list? I can’t think of any
other explanation…

Thanks

James

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