[PATCH 07/10] af_unix: implement poll(POLLOUT) for multicast sockets
From: Javier Martinez Canillas <hidden>
Date: 2012-02-20 16:33:27
Also in:
lkml
Subsystem:
networking [general], networking [unix sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Linus Torvalds
From: Alban Crequy <redacted> When a socket subscribed to a multicast group has its incoming queue full, it can either block the emission to the multicast group or let the messages be dropped. The latter is useful to monitor all messages without slowing down the traffic. It is specified with the flag UNIX_MREQ_DROP_WHEN_FULL when the multicast group is joined. poll(POLLOUT) is implemented by checking all receiving queues of subscribed sockets. If only one of them has its receiving queue full and does not have UNIX_MREQ_DROP_WHEN_FULL, the multicast socket is not writeable. Signed-off-by: Alban Crequy <redacted> Reviewed-by: Ian Molton <redacted> --- net/unix/af_unix.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 47 insertions(+), 0 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index a6b489c..bd9dc58 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -2974,6 +2974,11 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, { struct sock *sk = sock->sk, *other; unsigned int mask, writable; +#ifdef CONFIG_UNIX_MULTICAST + struct sock_set *others; + int err = 0; + int i; +#endif sock_poll_wait(file, sk_sleep(sk), wait); mask = 0;
@@ -3011,6 +3016,48 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, if (unix_recvq_full(other)) writable = 0; } + +#ifdef CONFIG_UNIX_MULTICAST + /* + * On multicast sockets, we need to check if the receiving + * queue is full on all peers who don't have + * UNIX_MREQ_DROP_WHEN_FULL. + */ + + /* Don't let the group die under us */ + unix_state_lock(other); + if (sock_flag(other, SOCK_DEAD) + || !unix_sk(other)->mcast_group) { + unix_state_unlock(other); + goto skip_multicast; + } + atomic_inc(&unix_sk(other)->mcast_group->refcnt); + unix_state_unlock(other); + + others = unix_find_multicast_recipients(sk, + unix_sk(other)->mcast_group, &err); + if (!others) + goto skip_multicast_peers; + for (i = others->offset ; i < others->cnt ; i++) { + if (others->items[i].flags & UNIX_MREQ_DROP_WHEN_FULL) + continue; + if (unix_peer(others->items[i].s) != sk) { + sock_poll_wait(file, + &unix_sk(others->items[i].s) + ->peer_wait, wait); + if (unix_recvq_full(others->items[i].s)) { + writable = 0; + break; + } + } + } + up_sock_set(others); +skip_multicast_peers: + if (atomic_dec_and_test(&unix_sk(other)->mcast_group->refcnt)) + destroy_mcast_group(unix_sk(other)->mcast_group); + +skip_multicast: +#endif sock_put(other); }
--
1.7.7.6