On Tue, 29 Nov 2011 22:56:26 +0100
Eric Dumazet [off-list ref] wrote:

Le mardi 29 novembre 2011 à 16:52 -0500, David Miller a écrit :

quoted

There is really no reason to keep the current behavior.

If an application sets the congestion control algorithm on a listening
socket to a non-default value, what effect could possibly be intended?

Congestion control doesn't even come into play at all on a listening
socket, therefore the only logical expectation is that it inherits to
the child.

The only other logical behavior would be to forbid this operation on a
listening socket, since it has no effect, but that doesn't make any
sense now does it? :-)

Moreover, an application can use setsockopt(TCP_CONGESTION) before
calling listen() (while socket is still in CLOSE state)

Agreed, it was just an oversight of the initial design.
The setsockopt() on the listening socket is ignored.