From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 31 Oct 2010 05:36:23 +0000 (+0000)
Subject: af_unix: fix unix_dgram_poll() behavior for EPOLLOUT event
X-Git-Tag: v2.6.38-rc1~476^2~621
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5456f09aaf88731e16dbcea7522cb330b6846415;p=pandora-kernel.git

af_unix: fix unix_dgram_poll() behavior for EPOLLOUT event

Alban Crequy reported a problem with connected dgram af_unix sockets and
provided a test program. epoll() would miss to send an EPOLLOUT event
when a thread unqueues a packet from the other peer, making its receive
queue not full.

This is because unix_dgram_poll() fails to call sock_poll_wait(file,
&unix_sk(other)->peer_wait, wait);
if the socket is not writeable at the time epoll_ctl(ADD) is called.

We must call sock_poll_wait(), regardless of 'writable' status, so that
epoll can be notified later of states changes.

Misc: avoids testing twice (sk->sk_shutdown & RCV_SHUTDOWN)

Reported-by: Alban Crequy <alban.crequy@collabora.co.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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