NFC: llcp: Fix non blocking sockets connections

Without the new LLCP_CONNECTING state, non blocking sockets will be
woken up with a POLLHUP right after calling connect() because their
state is stuck at LLCP_CLOSED.
That prevents userspace from implementing any proper non blocking
socket based NFC p2p client.

Cc: stable@vger.kernel.org
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 6 insertions, 3 deletions

diff --git a/net/nfc/llcp.h b/net/nfc/llcp.h
index 71f649e5ef49..f4d48b57ea11 100644
--- a/net/nfc/llcp.h
+++ b/net/nfc/llcp.h
@@ -19,6 +19,7 @@
 
 enum llcp_state {
         LLCP_CONNECTED = 1, /* wait_for_packet() wants that */
+        LLCP_CONNECTING,
         LLCP_DISCONNECTING,
         LLCP_CLOSED,
         LLCP_BOUND,
diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c
index 47e7acfc0236..d308402b67d8 100644
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -571,7 +571,7 @@ static unsigned int llcp_sock_poll(struct file *file, struct socket *sock,
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
 
-        if (sock_writeable(sk))
+        if (sock_writeable(sk) && sk->sk_state == LLCP_CONNECTED)
                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
         else
                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
@@ -729,14 +729,16 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
         if (ret)
                 goto sock_unlink;
 
+        sk->sk_state = LLCP_CONNECTING;
+
         ret = sock_wait_state(sk, LLCP_CONNECTED,
                               sock_sndtimeo(sk, flags & O_NONBLOCK));
-        if (ret)
+        if (ret && ret != -EINPROGRESS)
                 goto sock_unlink;
 
         release_sock(sk);
 
-        return 0;
+        return ret;
 
 sock_unlink:
         nfc_llcp_put_ssap(local, llcp_sock->ssap);