Re: [PATCHv4 10/18] Bluetooth: Add logical link confirm

[Marcel Holtmann <marcel@holtmann.org>]

Hi Mat,

> The logical link confirm callback is executed when the AMP controller
> completes its logical link setup.  During a channel move, a newly
> formed logical link allows a move responder to send a move channel
> response.  A move initiator will send a move channel confirm.  A
> failed logical link will end the channel move and send an appropriate
> response or confirm command indicating a failure.
> 
> If the channel is being created on an AMP controller, L2CAP
> configuration is completed after the logical link is set up.
> 
> Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
> ---
>  net/bluetooth/l2cap_core.c | 124 ++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 116 insertions(+), 8 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 69d43c9..0edc955 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3799,6 +3799,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
>  		goto unlock;
>  	}
>  
> +	chan->ident = cmd->ident;
>  	l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP, len, rsp);
>  	chan->num_conf_rsp++;
>  
> @@ -4198,17 +4199,17 @@ static int l2cap_create_channel_req(struct l2cap_conn *conn,
>  	return 0;
>  }
>  
> -static void l2cap_send_move_chan_rsp(struct l2cap_conn *conn, u8 ident,
> -				     u16 icid, u16 result)
> +static void l2cap_send_move_chan_rsp(struct l2cap_chan *chan, u16 result)
>  {
>  	struct l2cap_move_chan_rsp rsp;
>  
> -	BT_DBG("icid 0x%4.4x, result 0x%4.4x", icid, result);
> +	BT_DBG("chan %p, result 0x%4.4x", chan, result);
>  
> -	rsp.icid = cpu_to_le16(icid);
> +	rsp.icid = cpu_to_le16(chan->dcid);
>  	rsp.result = cpu_to_le16(result);
>  
> -	l2cap_send_cmd(conn, ident, L2CAP_MOVE_CHAN_RSP, sizeof(rsp), &rsp);
> +	l2cap_send_cmd(chan->conn, chan->ident, L2CAP_MOVE_CHAN_RSP,
> +		       sizeof(rsp), &rsp);
>  }
>  
>  static void l2cap_send_move_chan_cfm(struct l2cap_chan *chan, u16 result)
> @@ -4260,11 +4261,114 @@ static void __release_logical_link(struct l2cap_chan *chan)
>  	/* Placeholder - release the logical link */
>  }
>  
> +static void l2cap_logical_fail(struct l2cap_chan *chan)
> +{
> +	/* Logical link setup failed */
> +	if (chan->state != BT_CONNECTED) {
> +		/* Create channel failure, disconnect */
> +		l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);

lets do this:

	if (chan->state != BT_CONNECTED) {
		...
		return;
	}

> +	} else if (chan->move_role == L2CAP_MOVE_ROLE_RESPONDER) {
> +		l2cap_move_revert(chan);
> +		chan->move_role = L2CAP_MOVE_ROLE_NONE;
> +		chan->move_state = L2CAP_MOVE_STABLE;
> +		l2cap_send_move_chan_rsp(chan, L2CAP_MR_NOT_SUPP);
> +	} else if (chan->move_role == L2CAP_MOVE_ROLE_INITIATOR) {
> +		if (chan->move_state == L2CAP_MOVE_WAIT_LOGICAL_COMP ||
> +		    chan->move_state == L2CAP_MOVE_WAIT_LOGICAL_CFM) {
> +			/* Remote has only sent pending or
> +			 * success responses, clean up
> +			 */
> +			l2cap_move_revert(chan);
> +			chan->move_role = L2CAP_MOVE_ROLE_NONE;
> +			chan->move_state = L2CAP_MOVE_STABLE;
> +		}
> +
> +		/* Other amp move states imply that the move
> +		 * has already aborted
> +		 */
> +		l2cap_send_move_chan_cfm(chan, L2CAP_MC_UNCONFIRMED);
> +	}

And turn this into a switch statement.

> +
> +	__release_logical_link(chan);

And leave this to the caller.

> +}
> +
> +static void l2cap_logical_finish_create(struct l2cap_chan *chan,
> +					struct hci_chan *hchan)
> +{
> +	struct l2cap_conf_rsp rsp;
> +	u8 code;
> +
> +	chan->hs_hcon = hchan->conn;
> +	chan->hs_hcon->l2cap_data = chan->conn;
> +
> +	code = l2cap_build_conf_rsp(chan, &rsp,
> +				    L2CAP_CONF_SUCCESS, 0);
> +	l2cap_send_cmd(chan->conn, chan->ident, L2CAP_CONF_RSP, code,
> +		       &rsp);
> +	set_bit(CONF_OUTPUT_DONE, &chan->conf_state);
> +
> +	if (test_bit(CONF_INPUT_DONE, &chan->conf_state)) {
> +		int err = 0;
> +
> +		set_default_fcs(chan);
> +
> +		err = l2cap_ertm_init(chan);
> +		if (err < 0)
> +			l2cap_send_disconn_req(chan->conn, chan, -err);
> +		else
> +			l2cap_chan_ready(chan);
> +	}
> +}
> +
> +static void l2cap_logical_finish_move(struct l2cap_chan *chan,
> +				      struct hci_chan *hchan)
> +{
> +	chan->hs_hcon = hchan->conn;
> +	chan->hs_hcon->l2cap_data = chan->conn;
> +
> +	BT_DBG("move_state %d", chan->move_state);
> +
> +	switch (chan->move_state) {
> +	case L2CAP_MOVE_WAIT_LOGICAL_COMP:
> +		/* Move confirm will be sent after a success
> +		 * response is received
> +		 */
> +		chan->move_state = L2CAP_MOVE_WAIT_RSP_SUCCESS;
> +		break;
> +	case L2CAP_MOVE_WAIT_LOGICAL_CFM:
> +		if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
> +			chan->move_state = L2CAP_MOVE_WAIT_LOCAL_BUSY;

My brain just hurts from these nested if-else. A nested two switch does
not make it any better though. So we can leave it as this. Except the
statement below is used multiple places and we have a function for it.

> +		} else if (chan->move_role == L2CAP_MOVE_ROLE_INITIATOR) {
> +			chan->move_state = L2CAP_MOVE_WAIT_CONFIRM_RSP;
> +			l2cap_send_move_chan_cfm(chan, L2CAP_MC_CONFIRMED);
> +		} else if (chan->move_role == L2CAP_MOVE_ROLE_RESPONDER) {
> +			chan->move_state = L2CAP_MOVE_WAIT_CONFIRM;
> +			l2cap_send_move_chan_rsp(chan, L2CAP_MR_SUCCESS);
> +		}
> +		break;
> +	default:
> +		/* Move was not in expected state, free the channel */
> +		__release_logical_link(chan);
> +
> +		chan->move_state = L2CAP_MOVE_STABLE;
> +	}
> +}
> +
> +/* Call with chan locked */
>  static void l2cap_logical_cfm(struct l2cap_chan *chan, struct hci_chan *hchan,
>  			      u8 status)
>  {
> -	/* Placeholder */
> -	return;
> +	BT_DBG("chan %p, hchan %p, status %d", chan, hchan, status);
> +
> +	if (status) {
> +		l2cap_logical_fail(chan);

I rather have a return here.

	if (status) {
		l2cap_logical_fail(chan);
		__release_logical_link(chan);
		return;
	}

> +	} else if (chan->state != BT_CONNECTED) {
> +		/* Ignore logical link if channel is on BR/EDR */
> +		if (chan->local_amp_id)
> +			l2cap_logical_finish_create(chan, hchan);
> +	} else {
> +		l2cap_logical_finish_move(chan, hchan);
> +	}
>  }
>  
>  static inline int l2cap_move_channel_req(struct l2cap_conn *conn,
> @@ -4272,6 +4376,7 @@ static inline int l2cap_move_channel_req(struct l2cap_conn *conn,
>  					 u16 cmd_len, void *data)
>  {
>  	struct l2cap_move_chan_req *req = data;
> +	struct l2cap_move_chan_rsp rsp;
>  	struct l2cap_chan *chan;
>  	u16 icid = 0;
>  	u16 result = L2CAP_MR_NOT_ALLOWED;
> @@ -4348,7 +4453,10 @@ static inline int l2cap_move_channel_req(struct l2cap_conn *conn,
>  	}
>  
>  send_move_response:
> -	l2cap_send_move_chan_rsp(conn, cmd->ident, icid, result);
> +	rsp.icid = cpu_to_le16(icid);
> +	rsp.result = cpu_to_le16(result);
> +	l2cap_send_cmd(conn, cmd->ident, L2CAP_MOVE_CHAN_RSP,
> +		       sizeof(rsp), &rsp);
>  
>  	if (chan)
>  		l2cap_chan_unlock(chan);

While not part of this patch, I still dislike if (something) unlock
style. Please have that fixed as well.

Rest looks fine.

Regards

Marcel