[PATCH] Bluetooth: Simplify L2CAP Streaming mode sending

From: Gustavo F. Padovan
Date: Wed Sep 08 2010 - 19:32:38 EST


As we don't have any error control on the Streaming mode, i.e., we don't
need to keep a copy of the skb for later resending we don't need to
call skb_clone() on it.
Then we can go one further here, and dequeue the skb before sending it,
that also means we don't need to look to sk->sk_send_head anymore.

The patch saves memory and time when sending Streaming mode data, so
it is good to mainline.

Signed-off-by: Gustavo F. Padovan <padovan@xxxxxxxxxxxxxx>
---
net/bluetooth/l2cap.c | 24 +++++++-----------------
1 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 9fad312..f2062aa 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1441,33 +1441,23 @@ static inline void l2cap_do_send(struct sock *sk, struct sk_buff *skb)

static void l2cap_streaming_send(struct sock *sk)
{
- struct sk_buff *skb, *tx_skb;
+ struct sk_buff *skb;
struct l2cap_pinfo *pi = l2cap_pi(sk);
u16 control, fcs;

- while ((skb = sk->sk_send_head)) {
- tx_skb = skb_clone(skb, GFP_ATOMIC);
-
- control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+ while ((skb = skb_dequeue(TX_QUEUE(sk)))) {
+ control = get_unaligned_le16(skb->data + L2CAP_HDR_SIZE);
control |= pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT;
- put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
+ put_unaligned_le16(control, skb->data + L2CAP_HDR_SIZE);

if (pi->fcs == L2CAP_FCS_CRC16) {
- fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len - 2);
- put_unaligned_le16(fcs, tx_skb->data + tx_skb->len - 2);
+ fcs = crc16(0, (u8 *)skb->data, skb->len - 2);
+ put_unaligned_le16(fcs, skb->data + skb->len - 2);
}

- l2cap_do_send(sk, tx_skb);
+ l2cap_do_send(sk, skb);

pi->next_tx_seq = (pi->next_tx_seq + 1) % 64;
-
- if (skb_queue_is_last(TX_QUEUE(sk), skb))
- sk->sk_send_head = NULL;
- else
- sk->sk_send_head = skb_queue_next(TX_QUEUE(sk), skb);
-
- skb = skb_dequeue(TX_QUEUE(sk));
- kfree_skb(skb);
}
}

--
1.7.2.2

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