RE: udp sendfile & csum_partial work around

From: Ravi Chamarti (
Date: Fri Sep 06 2002 - 12:27:48 EST

Hi Dave,

What is wrong in udp_sendpages which is including header and trailers as a part of the
arguments? I don't quite understand the problem in the interface other than it is including
header and trailers as a part of sendfile call just like BSD-style sendfilev call.

Using CORKing for UDP is nothing but buffering UDP packets which is not conventional for UDP sockets. A write on UDP sockets do need to result in transmitting the packets to the network.

The patch is a initial attempt to provide a UDP-based zero-copy path and also solving IP frags
checksum issues in sending non-linear UDP skbs.

Ravi Chamarti

-----Original Message-----
From: David S. Miller []
Sent: Friday, September 06, 2002 11:58 AM
To: Kishore Chitrapu
Cc:; Larry Sendlosky; Ravi Chamarti;
Subject: Re: udp sendfile & csum_partial work around

Wrong interface, you need to do something like TCP_CORK
for udp, then the user does a write() of the headers
then a sendfile() then an uncork. When the uncork happens
you push the accumulated SKB to be transmitted.
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to
More majordomo info at

This archive was generated by hypermail 2b29 : Sat Sep 07 2002 - 22:00:02 EST