Hi Mat,
* Mat Martineau <mathewm@xxxxxxxxxxxxxx> [2011-06-29 14:35:23 -0700]:
> This change moves most L2CAP ERTM receive buffer handling out of the
> L2CAP core and in to the socket code. It's up to the higher layer
> (the socket code, in this case) to tell the core when its buffer is
> full or has space available. The recv op should always accept
> incoming ERTM data or else the connection will go down.
>
> Within the socket layer, an skb that does not fit in the socket
> receive buffer will be temporarily stored. When the socket is read
> from, that skb will be placed in the receive buffer if possible. Once
> adequate buffer space becomes available, the L2CAP core is informed
> and the ERTM local busy state is cleared.
>
> Receive buffer management for non-ERTM modes is unchanged.
>
> Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
> ---
> include/net/bluetooth/l2cap.h | 3 ++
> net/bluetooth/l2cap_core.c | 41 ++++++++++++++++---------
> net/bluetooth/l2cap_sock.c | 67 +++++++++++++++++++++++++++++++++++++++--
> 3 files changed, 93 insertions(+), 18 deletions(-)
>
> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
> index 9c18e55..82387c5 100644
> --- a/include/net/bluetooth/l2cap.h
> +++ b/include/net/bluetooth/l2cap.h
> @@ -422,6 +422,8 @@ struct l2cap_conn {
> struct l2cap_pinfo {
> struct bt_sock bt;
> struct l2cap_chan *chan;
> + struct sk_buff *rx_busy_skb;
> + int rx_busy;
> };
>
> enum {
> @@ -498,5 +500,6 @@ void l2cap_chan_close(struct l2cap_chan *chan, int reason);
> void l2cap_chan_destroy(struct l2cap_chan *chan);
> int l2cap_chan_connect(struct l2cap_chan *chan);
> int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len);
> +void l2cap_chan_busy(struct l2cap_chan *chan, int busy);
>
> #endif /* __L2CAP_H */
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 4b764b1..f0e7ba7 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3350,21 +3350,21 @@ static int l2cap_push_rx_skb(struct l2cap_chan *chan, struct sk_buff *skb, u16 c
> }
>
> err = l2cap_ertm_reassembly_sdu(chan, skb, control);
> - if (err >= 0) {
> - chan->buffer_seq = (chan->buffer_seq + 1) % 64;
> - return err;
> - }
> -
> - l2cap_ertm_enter_local_busy(chan);
> -
> - bt_cb(skb)->sar = control >> L2CAP_CTRL_SAR_SHIFT;
> - __skb_queue_tail(&chan->busy_q, skb);
> -
> - queue_work(_busy_wq, &chan->busy_work);
> + chan->buffer_seq = (chan->buffer_seq + 1) % 64;
>
> return err;
> }
>
> +void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
> +{
> + if (chan->mode == L2CAP_MODE_ERTM) {
> + if (busy)
> + l2cap_ertm_enter_local_busy(chan);
> + else
> + l2cap_ertm_exit_local_busy(chan);
> + }
> +}
> +
> static int l2cap_streaming_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
> {
> struct sk_buff *_skb;
> @@ -3463,13 +3463,22 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
> struct sk_buff *skb;
> u16 control;
>
> - while ((skb = skb_peek(&chan->srej_q))) {
> + while ((skb = skb_peek(&chan->srej_q)) &&
> + !test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
> + int err;
> +
> if (bt_cb(skb)->tx_seq != tx_seq)
> break;
>
> skb = skb_dequeue(&chan->srej_q);
> control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
> - l2cap_ertm_reassembly_sdu(chan, skb, control);
> + err = l2cap_ertm_reassembly_sdu(chan, skb, control);
> +
> + if (err < 0) {
> + l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
> + break;
> + }
> +
> chan->buffer_seq_srej =
> (chan->buffer_seq_srej + 1) % 64;
> tx_seq = (tx_seq + 1) % 64;
> @@ -3625,8 +3634,10 @@ expected:
> }
>
> err = l2cap_push_rx_skb(chan, skb, rx_control);
> - if (err < 0)
> - return 0;
> + if (err < 0) {
> + l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
> + return err;
> + }
>
> if (rx_control & L2CAP_CTRL_FINAL) {
> if (!test_and_clear_bit(CONN_REJ_ACT, &chan->conn_state))
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 39082d4..ab0494b 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -711,6 +711,8 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
> static int l2cap_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len, int flags)
> {
> struct sock *sk = sock->sk;
> + struct l2cap_pinfo *pi = l2cap_pi(sk);
> + int err;
>
> lock_sock(sk);
>
> @@ -725,9 +727,40 @@ static int l2cap_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct ms
> release_sock(sk);
>
> if (sock->type == SOCK_STREAM)
> - return bt_sock_stream_recvmsg(iocb, sock, msg, len, flags);
> + err = bt_sock_stream_recvmsg(iocb, sock, msg, len, flags);
> + else
> + err = bt_sock_recvmsg(iocb, sock, msg, len, flags);
> +
> + if (pi->chan->mode == L2CAP_MODE_ERTM) {
> + int queue_err;
> + int threshold;
> +
> + /* Attempt to put pending rx data in the socket buffer */
> +
> + lock_sock(sk);
> + if (pi->rx_busy_skb) {
> + queue_err = sock_queue_rcv_skb(sk, pi->rx_busy_skb);
> +
> + if (!queue_err)
> + pi->rx_busy_skb = NULL;
> + }
> +
> + /* Restore data flow when half of the receive buffer is
> + * available. This avoids resending large numbers of
> + * frames.
> + */
> + threshold = sk->sk_rcvbuf >> 1;
> + if (pi->rx_busy && !pi->rx_busy_skb &&
> + atomic_read(&sk->sk_rmem_alloc) <= threshold) {
> +
> + pi->rx_busy = 0;
> + l2cap_chan_busy(l2cap_pi(sk)->chan, pi->rx_busy);
> + }
> +
> + release_sock(sk);
This is to much core logic outside of the core. I didn't think hard on this
but this can be simplified to just read the threshold and report core if we
are not busy anymore, and then get rid of rx_busy and rx_busy_skb.
> + }
>
> - return bt_sock_recvmsg(iocb, sock, msg, len, flags);
> + return err;
> }
>
> /* Kill socket (only if zapped and orphan)
> @@ -811,9 +844,32 @@ static struct l2cap_chan *l2cap_sock_new_connection_cb(void *data)
>
> static int l2cap_sock_recv_cb(void *data, struct sk_buff *skb)
> {
> + int err;
> struct sock *sk = data;
> + struct l2cap_pinfo *pi = l2cap_pi(sk);
> +
> + if (pi->rx_busy_skb)
> + return -ENOMEM;
> +
> + err = sock_queue_rcv_skb(sk, skb);
> +
> + /* For ERTM, handle one skb that doesn't fit into the recv
> + * buffer. This is important to do because the data frames
> + * have already been acked, so the skb cannot be discarded.
> + *
> + * Notify the l2cap core that the buffer is full, so the
> + * LOCAL_BUSY state is entered and no more frames are
> + * acked and reassembled until there is buffer space
> + * available.
> + */
> + if (err < 0 && pi->chan->mode == L2CAP_MODE_ERTM) {
> + pi->rx_busy = 1;
> + pi->rx_busy_skb = skb;
> + l2cap_chan_busy(pi->chan, pi->rx_busy);
> + err = 0;
> + }
This can totally be in l2cap_core.c. The idea is move Core stuff to
l2cap_core.c and not let the L2CAP users handle this. Just enter in LOCAL_BUSY
when recv_cb returns returns less than 0.
Gustavo
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