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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-31 05:36:23 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-11-08 13:50:09 -0800 |
| commit | 5456f09aaf88731e16dbcea7522cb330b6846415 (patch) | |
| tree | eac95420f5da87dc95342aa23d9a97653544863d /net/unix | |
| parent | 67426b756c4d52c511c4b22b269accea171692a8 (diff) | |
| download | linux-5456f09aaf88731e16dbcea7522cb330b6846415.tar.gz linux-5456f09aaf88731e16dbcea7522cb330b6846415.tar.bz2 linux-5456f09aaf88731e16dbcea7522cb330b6846415.zip | |
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>
Diffstat (limited to 'net/unix')
| -rw-r--r-- | net/unix/af_unix.c | 24 |
1 files changed, 9 insertions, 15 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index f33c5958dbb2..e8898758dd31 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2074,13 +2074,12 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) mask |= POLLERR; if (sk->sk_shutdown & RCV_SHUTDOWN) - mask |= POLLRDHUP; + mask |= POLLRDHUP | POLLIN | POLLRDNORM; if (sk->sk_shutdown == SHUTDOWN_MASK) mask |= POLLHUP; /* readable? */ - if (!skb_queue_empty(&sk->sk_receive_queue) || - (sk->sk_shutdown & RCV_SHUTDOWN)) + if (!skb_queue_empty(&sk->sk_receive_queue)) mask |= POLLIN | POLLRDNORM; /* Connection-based need to check for termination and startup */ @@ -2092,20 +2091,15 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, return mask; } - /* writable? */ writable = unix_writable(sk); - if (writable) { - other = unix_peer_get(sk); - if (other) { - if (unix_peer(other) != sk) { - sock_poll_wait(file, &unix_sk(other)->peer_wait, - wait); - if (unix_recvq_full(other)) - writable = 0; - } - - sock_put(other); + other = unix_peer_get(sk); + if (other) { + if (unix_peer(other) != sk) { + sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); + if (unix_recvq_full(other)) + writable = 0; } + sock_put(other); } if (writable) |