Re: [PATCH 07/19] Bluetooth: Add move channel confirm handling

[Marcel Holtmann <marcel@holtmann.org>]

Hi Mat,

> After sending a move channel response, a move responder waits for a
> move channel confirm command.  If the received command has a
> "confirmed" result the move is proceeding, and "unconfirmed" means the
> move has failed and the channel will not change controllers.
> 
> Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
> ---
>  net/bluetooth/l2cap_core.c | 70 ++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 67 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index aab7f79..ef744a9 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -1030,6 +1030,42 @@ static void l2cap_move_setup(struct l2cap_chan *chan)
>  	set_bit(CONN_REMOTE_BUSY, &chan->conn_state);
>  }
>  
> +static void l2cap_move_success(struct l2cap_chan *chan)
> +{
> +	BT_DBG("chan %p", chan);
> +
> +	if (chan->mode != L2CAP_MODE_ERTM)
> +		return;
> +
> +	switch (chan->move_role) {
> +	case L2CAP_MOVE_ROLE_INITIATOR:
> +		l2cap_tx(chan, NULL, NULL, L2CAP_EV_EXPLICIT_POLL);
> +		chan->rx_state = L2CAP_RX_STATE_WAIT_F;
> +		break;
> +	case L2CAP_MOVE_ROLE_RESPONDER:
> +		chan->rx_state = L2CAP_RX_STATE_WAIT_P;
> +		break;
> +	}
> +}
> +
> +static void l2cap_move_revert(struct l2cap_chan *chan)
> +{
> +	BT_DBG("chan %p", chan);
> +
> +	if (chan->mode != L2CAP_MODE_ERTM)
> +		return;
> +
> +	switch (chan->move_role) {
> +	case L2CAP_MOVE_ROLE_INITIATOR:
> +		l2cap_tx(chan, NULL, NULL, L2CAP_EV_EXPLICIT_POLL);
> +		chan->rx_state = L2CAP_RX_STATE_WAIT_F;
> +		break;
> +	case L2CAP_MOVE_ROLE_RESPONDER:
> +		chan->rx_state = L2CAP_RX_STATE_WAIT_P;
> +		break;
> +	}
> +}
> +
>  static void l2cap_chan_ready(struct l2cap_chan *chan)
>  {
>  	/* This clears all conf flags, including CONF_NOT_COMPLETE */
> @@ -4297,11 +4333,12 @@ static inline int l2cap_move_channel_rsp(struct l2cap_conn *conn,
>  	return 0;
>  }
>  
> -static inline int l2cap_move_channel_confirm(struct l2cap_conn *conn,
> -					     struct l2cap_cmd_hdr *cmd,
> -					     u16 cmd_len, void *data)
> +static int l2cap_move_channel_confirm(struct l2cap_conn *conn,
> +				      struct l2cap_cmd_hdr *cmd,
> +				      u16 cmd_len, void *data)
>  {
>  	struct l2cap_move_chan_cfm *cfm = data;
> +	struct l2cap_chan *chan;
>  	u16 icid, result;
>  
>  	if (cmd_len != sizeof(*cfm))
> @@ -4312,8 +4349,35 @@ static inline int l2cap_move_channel_confirm(struct l2cap_conn *conn,
>  
>  	BT_DBG("icid 0x%4.4x, result 0x%4.4x", icid, result);
>  
> +	chan = l2cap_get_chan_by_dcid(conn, icid);
> +	if (!chan)
> +		goto send_move_confirm_response;
> +
> +	if (chan->move_state == L2CAP_MOVE_WAIT_CONFIRM) {
> +		chan->move_state = L2CAP_MOVE_STABLE;
> +		if (result == L2CAP_MC_CONFIRMED) {
> +			chan->local_amp_id = chan->move_id;
> +			if (!chan->local_amp_id) {
> +				/* Have moved off of AMP, free the channel */
> +				chan->hs_hchan = NULL;
> +				chan->hs_hcon = NULL;
> +
> +				/* Placeholder - free the logical link */
> +			}
> +			l2cap_move_success(chan);
> +		} else {
> +			chan->move_id = chan->local_amp_id;
> +			l2cap_move_revert(chan);
> +		}
> +		chan->move_role = L2CAP_MOVE_ROLE_NONE;
> +	}
> +
> +send_move_confirm_response:
>  	l2cap_send_move_chan_cfm_rsp(conn, cmd->ident, icid);
>  
> +	if (chan)
> +		l2cap_chan_unlock(chan);
> +
>  	return 0;
>  }
>  

the more I read into this one, can we not have a clean exit when (!chan)
for this one. Or am I missing something.

Regards

Marcel