Commit 5b440676 authored by Archie Pusaka's avatar Archie Pusaka Committed by Marcel Holtmann
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Bluetooth: L2CAP: add support for waiting disconnection resp 



Whenever we disconnect a L2CAP connection, we would immediately
report a disconnection event (EPOLLHUP) to the upper layer, without
waiting for the response of the other device.

This patch offers an option to wait until we receive a disconnection
response before reporting disconnection event, by using the "how"
parameter in l2cap_sock_shutdown(). Therefore, upper layer can opt
to wait for disconnection response by shutdown(sock, SHUT_WR).

This can be used to enforce proper disconnection order in HID,
where the disconnection of the interrupt channel must be complete
before attempting to disconnect the control channel.

Signed-off-by: default avatarArchie Pusaka <apusaka@chromium.org>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent adf1d692

net/bluetooth/l2cap_sock.c

+23 −7
Original line number Diff line number Diff line
@@ -1271,14 +1271,21 @@ static int l2cap_sock_shutdown(struct socket *sock, int how) 
	struct l2cap_conn *conn;

	int err = 0;



	BT_DBG("sock %p, sk %p", sock, sk);

	BT_DBG("sock %p, sk %p, how %d", sock, sk, how);



	/* 'how' parameter is mapped to sk_shutdown as follows:

	 * SHUT_RD   (0) --> RCV_SHUTDOWN  (1)

	 * SHUT_WR   (1) --> SEND_SHUTDOWN (2)

	 * SHUT_RDWR (2) --> SHUTDOWN_MASK (3)

	 */

	how++;



	if (!sk)

		return 0;



	lock_sock(sk);



	if (sk->sk_shutdown)

	if ((sk->sk_shutdown & how) == how)

		goto shutdown_already;



	BT_DBG("Handling sock shutdown");
@@ -1301,11 +1308,20 @@ static int l2cap_sock_shutdown(struct socket *sock, int how) 
		 * has already been actioned to close the L2CAP

		 * link such as by l2cap_disconnection_req().

		 */

		if (sk->sk_shutdown)

			goto has_shutdown;

		if ((sk->sk_shutdown & how) == how)

			goto shutdown_matched;

	}



	sk->sk_shutdown = SHUTDOWN_MASK;

	/* Try setting the RCV_SHUTDOWN bit, return early if SEND_SHUTDOWN

	 * is already set

	 */

	if ((how & RCV_SHUTDOWN) && !(sk->sk_shutdown & RCV_SHUTDOWN)) {

		sk->sk_shutdown |= RCV_SHUTDOWN;

		if ((sk->sk_shutdown & how) == how)

			goto shutdown_matched;

	}



	sk->sk_shutdown |= SEND_SHUTDOWN;

	release_sock(sk);



	l2cap_chan_lock(chan);
@@ -1335,7 +1351,7 @@ static int l2cap_sock_shutdown(struct socket *sock, int how) 
		err = bt_sock_wait_state(sk, BT_CLOSED,

					 sk->sk_lingertime);



has_shutdown:

shutdown_matched:

	l2cap_chan_put(chan);

	sock_put(sk);
@@ -1363,7 +1379,7 @@ static int l2cap_sock_release(struct socket *sock) 


	bt_sock_unlink(&l2cap_sk_list, sk);



	err = l2cap_sock_shutdown(sock, 2);

	err = l2cap_sock_shutdown(sock, SHUT_RDWR);

	chan = l2cap_pi(sk)->chan;



	l2cap_chan_hold(chan);

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