[net-next PATCH 7/9] bpf: sockmap indicate sock events to listeners

[John Fastabend]

After userspace pushes sockets into a sockmap it may not be receiving
data (assuming stream_{parser|verdict} programs are attached). But, it
may still want to manage the socks. A common pattern is to poll/select
for a POLLRDHUP event so we can close the sock.

This patch adds the logic to wake up these listeners.

Also add TCP_SYN_SENT to the list of events to handle. We don't want
to break the connection just because we happen to be in this state.

Signed-off-by: John Fastabend <john.fastab...@gmail.com>
---
 kernel/bpf/sockmap.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 38bf4e4..bcc326a 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -162,6 +162,7 @@ static void smap_state_change(struct sock *sk)
 {
        struct smap_psock_map_entry *e, *tmp;
        struct smap_psock *psock;
+       struct socket_wq *wq;
        struct sock *osk;
 
        rcu_read_lock();
@@ -171,6 +172,7 @@ static void smap_state_change(struct sock *sk)
         * is established.
         */
        switch (sk->sk_state) {
+       case TCP_SYN_SENT:
        case TCP_SYN_RECV:
        case TCP_ESTABLISHED:
                break;
@@ -208,6 +210,10 @@ static void smap_state_change(struct sock *sk)
                smap_report_sk_error(psock, EPIPE);
                break;
        }
+
+       wq = rcu_dereference(sk->sk_wq);
+       if (skwq_has_sleeper(wq))
+               wake_up_interruptible_all(&wq->wait);
        rcu_read_unlock();
 }