udp: Simplify updates to UDP flow timestamp

Since UDP has no built in knowledge of connections, the only way we
know when we're done with a UDP flow is a timeout with no activity.
To keep track of this struct udp_flow includes a timestamp to record
the last time we saw traffic on the flow.

For data from listening sockets and from tap, this is done implicitly via
udp_flow_from_{sock,tap}() but for reply sockets it's done explicitly.
However, that logic is duplicated between the vhost-user and "buf" paths.
Make it common in udp_reply_sock_handler() instead.

Technically this is a behavioural change: previously if we got an EPOLLIN
event, but there wasn't actually any data we wouldn't update the timestamp,
now we will.  This should be harmless: if there's an EPOLLIN we expect
there to be data, and even if there isn't the worst we can do is mildly
delay the cleanup of a stale flow.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

0 files changed, 0 insertions, 0 deletions