Re: [PATCH -v2 4/8] Bluetooth: Add chan->ops->defer()

[Marcel Holtmann <marcel@holtmann.org>]

Hi Gustavo,

> When DEFER_SETUP is set defer() will trigger an authorization
> request to the userspace.
> 
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> ---
>  include/net/bluetooth/l2cap.h |  5 +++++
>  net/bluetooth/a2mp.c          |  1 +
>  net/bluetooth/l2cap_core.c    | 10 +++-------
>  net/bluetooth/l2cap_sock.c    | 13 +++++++++++++
>  4 files changed, 22 insertions(+), 7 deletions(-)
> 
> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
> index caab98c..6e23afd 100644
> --- a/include/net/bluetooth/l2cap.h
> +++ b/include/net/bluetooth/l2cap.h
> @@ -541,6 +541,7 @@ struct l2cap_ops {
>  	void			(*state_change) (struct l2cap_chan *chan,
>  						 int state);
>  	void			(*ready) (struct l2cap_chan *chan);
> +	void			(*defer) (struct l2cap_chan *chan);
>  	struct sk_buff		*(*alloc_skb) (struct l2cap_chan *chan,
>  					       unsigned long len, int nb);
>  };
> @@ -748,6 +749,10 @@ static inline void l2cap_chan_no_ready(struct l2cap_chan *chan)
>  {
>  }
>  
> +static inline void l2cap_chan_no_defer(struct l2cap_chan *chan)
> +{
> +}
> +
>  extern bool disable_ertm;
>  
>  int l2cap_init_sockets(void);
> diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
> index 3ff4dc9..7bf9a10 100644
> --- a/net/bluetooth/a2mp.c
> +++ b/net/bluetooth/a2mp.c
> @@ -699,6 +699,7 @@ static struct l2cap_ops a2mp_chan_ops = {
>  	.new_connection = l2cap_chan_no_new_connection,
>  	.teardown = l2cap_chan_no_teardown,
>  	.ready = l2cap_chan_no_ready,
> +	.defer = l2cap_chan_no_defer,
>  };
>  
>  static struct l2cap_chan *a2mp_chan_open(struct l2cap_conn *conn, bool locked)
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 91d312b..a2f945d 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -1123,11 +1123,9 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
>  				lock_sock(sk);
>  				if (test_bit(BT_SK_DEFER_SETUP,
>  					     &bt_sk(sk)->flags)) {
> -					struct sock *parent = bt_sk(sk)->parent;
>  					rsp.result = __constant_cpu_to_le16(L2CAP_CR_PEND);
>  					rsp.status = __constant_cpu_to_le16(L2CAP_CS_AUTHOR_PEND);
> -					if (parent)
> -						parent->sk_data_ready(parent, 0);
> +					chan->ops->defer(chan);

I would prefer you explain this in detail. Sine the no_defer is then no
longer calling sk_data_ready. Is this safe?

>  
>  				} else {
>  					__l2cap_state_change(chan, BT_CONFIG);
> @@ -3459,7 +3457,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn,
>  				__l2cap_state_change(chan, BT_CONNECT2);
>  				result = L2CAP_CR_PEND;
>  				status = L2CAP_CS_AUTHOR_PEND;
> -				parent->sk_data_ready(parent, 0);
> +				chan->ops->defer(chan);
>  			} else {
>  				__l2cap_state_change(chan, BT_CONFIG);
>  				result = L2CAP_CR_SUCCESS;
> @@ -5520,11 +5518,9 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
>  			if (!status) {
>  				if (test_bit(BT_SK_DEFER_SETUP,
>  					     &bt_sk(sk)->flags)) {
> -					struct sock *parent = bt_sk(sk)->parent;
>  					res = L2CAP_CR_PEND;
>  					stat = L2CAP_CS_AUTHOR_PEND;
> -					if (parent)
> -						parent->sk_data_ready(parent, 0);
> +					chan->ops->defer(chan);
>  				} else {
>  					__l2cap_state_change(chan, BT_CONFIG);
>  					res = L2CAP_CR_SUCCESS;
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 45c81e1..efcb914 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -956,6 +956,7 @@ static struct l2cap_chan *l2cap_sock_new_connection_cb(struct l2cap_chan *chan)
>  
>  	bt_accept_enqueue(parent, sk);
>  
> +

No pointless empty lines please.

>  	release_sock(parent);
>  
>  	return l2cap_pi(sk)->chan;
> @@ -1088,6 +1089,17 @@ static void l2cap_sock_ready_cb(struct l2cap_chan *chan)
>  	release_sock(sk);
>  }
>  
> +static void l2cap_sock_defer_cb(struct l2cap_chan *chan)
> +{
> +	struct sock *sk = chan->data;
> +	struct sock *parent;
> +
> +	parent = bt_sk(sk)->parent;

You can do struct sock *parent = bt_sk(sk)-parent here.

> +
> +	if (parent)
> +		parent->sk_data_ready(parent, 0);
> +}
> +
>  static struct l2cap_ops l2cap_chan_ops = {
>  	.name		= "L2CAP Socket Interface",
>  	.new_connection	= l2cap_sock_new_connection_cb,
> @@ -1096,6 +1108,7 @@ static struct l2cap_ops l2cap_chan_ops = {
>  	.teardown	= l2cap_sock_teardown_cb,
>  	.state_change	= l2cap_sock_state_change_cb,
>  	.ready		= l2cap_sock_ready_cb,
> +	.defer		= l2cap_sock_defer_cb,
>  	.alloc_skb	= l2cap_sock_alloc_skb_cb,
>  };
>  

I am bit unease with accidentally having no_defer and then DEFER_SETUP
is set. Are we not changing behavior here?
Regards

Marcel