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authorEric Dumazet <eric.dumazet@gmail.com>2010-10-31 05:36:23 +0000
committerDavid S. Miller <davem@davemloft.net>2010-11-08 13:50:09 -0800
commit5456f09aaf88731e16dbcea7522cb330b6846415 (patch)
treeeac95420f5da87dc95342aa23d9a97653544863d /net/unix
parent67426b756c4d52c511c4b22b269accea171692a8 (diff)
downloadlinux-5456f09aaf88731e16dbcea7522cb330b6846415.tar.bz2
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.c24
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)