Hi Mat,
* Mat Martineau <mathewm@xxxxxxxxxxxxxx> [2011-07-13 10:58:39 -0700]:
> Use sk_buff fragment capabilities to link together incoming skbs
> instead of allocating a new skb for reassembly and copying.
>
> The new reassembly code works equally well for ERTM and streaming
> mode, so there is now one reassembly function instead of two.
>
> Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
> ---
> include/net/bluetooth/l2cap.h | 3 +-
> net/bluetooth/l2cap_core.c | 239 ++++++++++++++---------------------------
> 2 files changed, 80 insertions(+), 162 deletions(-)
>
> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
> index 4f34ad2..6fa1140 100644
> --- a/include/net/bluetooth/l2cap.h
> +++ b/include/net/bluetooth/l2cap.h
> @@ -354,8 +354,8 @@ struct l2cap_chan {
> __u8 retry_count;
> __u8 num_acked;
> __u16 sdu_len;
> - __u16 partial_sdu_len;
> struct sk_buff *sdu;
> + struct sk_buff *sdu_last_frag;
>
> __u8 remote_tx_win;
> __u8 remote_max_tx;
> @@ -454,7 +454,6 @@ enum {
> #define L2CAP_CONF_MAX_CONF_RSP 2
>
> enum {
> - CONN_SAR_SDU,
> CONN_SREJ_SENT,
> CONN_WAIT_F,
> CONN_SREJ_ACT,
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 52c791e..e82fff1 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3120,102 +3120,104 @@ static int l2cap_add_to_srej_queue(struct l2cap_chan *chan, struct sk_buff *skb,
> return 0;
> }
>
> -static int l2cap_ertm_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
> +static void append_skb_frag(struct sk_buff *skb,
> + struct sk_buff *new_frag, struct sk_buff **last_frag)
> {
> - struct sk_buff *_skb;
> - int err;
> + /* skb->len reflects data in skb as well as all fragments
> + * skb->data_len reflects only data in fragments
> + */
> + if (!skb_has_frag_list(skb))
> + skb_shinfo(skb)->frag_list = new_frag;
> +
> + new_frag->next = NULL;
> +
> + (*last_frag)->next = new_frag;
> + *last_frag = new_frag;
> +
> + skb->len += new_frag->len;
> + skb->data_len += new_frag->len;
> + skb->truesize += new_frag->truesize;
> +}
> +
> +static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
> +{
> + int err = -EINVAL;
>
> switch (control & L2CAP_CTRL_SAR) {
> case L2CAP_SDU_UNSEGMENTED:
> - if (test_bit(CONN_SAR_SDU, &chan->conn_state))
> - goto drop;
> + if (chan->sdu)
> + break;
>
> - return chan->ops->recv(chan->data, skb);
> + err = chan->ops->recv(chan->data, skb);
> + break;
>
> case L2CAP_SDU_START:
> - if (test_bit(CONN_SAR_SDU, &chan->conn_state))
> - goto drop;
> + if (chan->sdu)
> + break;
>
> chan->sdu_len = get_unaligned_le16(skb->data);
> + skb_pull(skb, 2);
>
> - if (chan->sdu_len > chan->imtu)
> - goto disconnect;
> -
> - chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
> - if (!chan->sdu)
> - return -ENOMEM;
> + if (chan->sdu_len > chan->imtu) {
> + err = -EMSGSIZE;
> + break;
> + }
>
> - /* pull sdu_len bytes only after alloc, because of Local Busy
> - * condition we have to be sure that this will be executed
> - * only once, i.e., when alloc does not fail */
> - skb_pull(skb, 2);
> + if (skb->len >= chan->sdu_len)
> + break;
>
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> + chan->sdu = skb;
> + chan->sdu_last_frag = skb;
>
> - set_bit(CONN_SAR_SDU, &chan->conn_state);
> - chan->partial_sdu_len = skb->len;
> + skb = NULL;
> + err = 0;
> break;
>
> case L2CAP_SDU_CONTINUE:
> - if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
> - goto disconnect;
> -
> if (!chan->sdu)
> - goto disconnect;
> + break;
>
> - chan->partial_sdu_len += skb->len;
> - if (chan->partial_sdu_len > chan->sdu_len)
> - goto drop;
> + append_skb_frag(chan->sdu, skb,
> + &chan->sdu_last_frag);
> + skb = NULL;
>
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> + if (chan->sdu->len >= chan->sdu_len)
> + break;
>
> + err = 0;
> break;
>
> case L2CAP_SDU_END:
> - if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
> - goto disconnect;
> -
> if (!chan->sdu)
> - goto disconnect;
> -
> - chan->partial_sdu_len += skb->len;
> -
> - if (chan->partial_sdu_len > chan->imtu)
> - goto drop;
> + break;
>
> - if (chan->partial_sdu_len != chan->sdu_len)
> - goto drop;
> + append_skb_frag(chan->sdu, skb,
> + &chan->sdu_last_frag);
> + skb = NULL;
>
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> + if (chan->sdu->len != chan->sdu_len)
> + break;
>
> - _skb = skb_clone(chan->sdu, GFP_ATOMIC);
> - if (!_skb) {
> - return -ENOMEM;
> - }
> + err = chan->ops->recv(chan->data, chan->sdu);
>
> - err = chan->ops->recv(chan->data, _skb);
> - if (err < 0) {
> - kfree_skb(_skb);
> - return err;
> + if (!err) {
> + /* Reassembly complete */
> + chan->sdu = NULL;
> + chan->sdu_last_frag = NULL;
> + chan->sdu_len = 0;
> }
> -
> - clear_bit(CONN_SAR_SDU, &chan->conn_state);
> -
> - kfree_skb(chan->sdu);
> break;
> }
>
> - kfree_skb(skb);
> - return 0;
> -
> -drop:
> - kfree_skb(chan->sdu);
> - chan->sdu = NULL;
> + if (err) {
> + kfree_skb(skb);
> + kfree_skb(chan->sdu);
> + chan->sdu = NULL;
> + chan->sdu_last_frag = NULL;
> + chan->sdu_len = 0;
> + }
>
> -disconnect:
> - l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
> - kfree_skb(skb);
> - return 0;
> + return err;
> }
>
> static void l2cap_ertm_enter_local_busy(struct l2cap_chan *chan)
> @@ -3269,99 +3271,6 @@ void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
> }
> }
>
> -static int l2cap_streaming_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
> -{
> - struct sk_buff *_skb;
> - int err = -EINVAL;
> -
> - /*
> - * TODO: We have to notify the userland if some data is lost with the
> - * Streaming Mode.
> - */
> -
> - switch (control & L2CAP_CTRL_SAR) {
> - case L2CAP_SDU_UNSEGMENTED:
> - if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
> - kfree_skb(chan->sdu);
> - break;
> - }
> -
> - err = chan->ops->recv(chan->data, skb);
> - if (!err)
> - return 0;
> -
> - break;
> -
> - case L2CAP_SDU_START:
> - if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
> - kfree_skb(chan->sdu);
> - break;
> - }
> -
> - chan->sdu_len = get_unaligned_le16(skb->data);
> - skb_pull(skb, 2);
> -
> - if (chan->sdu_len > chan->imtu) {
> - err = -EMSGSIZE;
> - break;
> - }
> -
> - chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
> - if (!chan->sdu) {
> - err = -ENOMEM;
> - break;
> - }
> -
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> -
> - set_bit(CONN_SAR_SDU, &chan->conn_state);
> - chan->partial_sdu_len = skb->len;
> - err = 0;
> - break;
> -
> - case L2CAP_SDU_CONTINUE:
> - if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
> - break;
> -
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> -
> - chan->partial_sdu_len += skb->len;
> - if (chan->partial_sdu_len > chan->sdu_len)
> - kfree_skb(chan->sdu);
> - else
> - err = 0;
> -
> - break;
> -
> - case L2CAP_SDU_END:
> - if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
> - break;
> -
> - memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
> -
> - clear_bit(CONN_SAR_SDU, &chan->conn_state);
> - chan->partial_sdu_len += skb->len;
> -
> - if (chan->partial_sdu_len > chan->imtu)
> - goto drop;
> -
> - if (chan->partial_sdu_len == chan->sdu_len) {
> - _skb = skb_clone(chan->sdu, GFP_ATOMIC);
> - err = chan->ops->recv(chan->data, _skb);
> - if (err < 0)
> - kfree_skb(_skb);
> - }
> - err = 0;
> -
> -drop:
> - kfree_skb(chan->sdu);
> - break;
> - }
> -
> - kfree_skb(skb);
> - return err;
> -}
> -
> static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
> {
> struct sk_buff *skb;
> @@ -3376,7 +3285,7 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
>
> skb = skb_dequeue(&chan->srej_q);
> control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
> - err = l2cap_ertm_reassembly_sdu(chan, skb, control);
> + err = l2cap_reassemble_sdu(chan, skb, control);
>
> if (err < 0) {
> l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
> @@ -3536,7 +3445,7 @@ expected:
> return 0;
> }
>
> - err = l2cap_ertm_reassembly_sdu(chan, skb, rx_control);
> + err = l2cap_reassemble_sdu(chan, skb, rx_control);
> chan->buffer_seq = (chan->buffer_seq + 1) % 64;
> if (err < 0) {
> l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
> @@ -3854,10 +3763,20 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
>
> if (chan->expected_tx_seq == tx_seq)
> chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
Coding style issue: you also need {} in the 'if'. If you need it on 'else'
then also add it to 'if.'
> - else
> + else {
Gustavo
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