From e328140fdacbba43292a59a22fb55d9185288318 Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Thu, 7 Jul 2011 09:39:02 -0700 Subject: [PATCH] Bluetooth: Use event-driven approach for handling ERTM receive buffer 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 Signed-off-by: Gustavo F. Padovan --- include/net/bluetooth/l2cap.h | 2 ++ net/bluetooth/l2cap_core.c | 41 ++++++++++++++-------- net/bluetooth/l2cap_sock.c | 65 ++++++++++++++++++++++++++++++++--- 3 files changed, 89 insertions(+), 19 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 9c18e555b6e..66b8d9688d9 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -422,6 +422,7 @@ struct l2cap_conn { struct l2cap_pinfo { struct bt_sock bt; struct l2cap_chan *chan; + struct sk_buff *rx_busy_skb; }; enum { @@ -498,5 +499,6 @@ 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 f7ada4a2cc5..ea9c7d06104 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 39082d4e77c..146b614d10e 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -711,13 +711,15 @@ 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); if (sk->sk_state == BT_CONNECT2 && bt_sk(sk)->defer_setup) { sk->sk_state = BT_CONFIG; - __l2cap_connect_rsp_defer(l2cap_pi(sk)->chan); + __l2cap_connect_rsp_defer(pi->chan); release_sock(sk); return 0; } @@ -725,9 +727,37 @@ 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) + return err; + + /* Attempt to put pending rx data in the socket buffer */ + + lock_sock(sk); + + if (!test_bit(CONN_LOCAL_BUSY, &pi->chan->conn_state)) + goto done; + + if (pi->rx_busy_skb) { + if (!sock_queue_rcv_skb(sk, pi->rx_busy_skb)) + pi->rx_busy_skb = NULL; + else + goto done; + } - return bt_sock_recvmsg(iocb, sock, msg, len, flags); + /* Restore data flow when half of the receive buffer is + * available. This avoids resending large numbers of + * frames. + */ + if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf >> 1) + l2cap_chan_busy(pi->chan, 0); + +done: + release_sock(sk); + return err; } /* Kill socket (only if zapped and orphan) @@ -811,9 +841,31 @@ 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); - return sock_queue_rcv_skb(sk, skb); + 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_skb = skb; + l2cap_chan_busy(pi->chan, 1); + err = 0; + } + + return err; } static void l2cap_sock_close_cb(void *data) @@ -842,6 +894,11 @@ static void l2cap_sock_destruct(struct sock *sk) { BT_DBG("sk %p", sk); + if (l2cap_pi(sk)->rx_busy_skb) { + kfree_skb(l2cap_pi(sk)->rx_busy_skb); + l2cap_pi(sk)->rx_busy_skb = NULL; + } + skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&sk->sk_write_queue); } -- 2.41.0