Bluetooth: Use explicit header and body length for L2CAP SKB allocation

When allocating the L2CAP SKB for transmission, provide the upper layers
with a clear distinction on what is the header and what is the body
portion of the SKB.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index d95964c..55215eb 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1292,6 +1292,7 @@
 }
 
 static struct sk_buff *l2cap_sock_alloc_skb_cb(struct l2cap_chan *chan,
+					       unsigned long hdr_len,
 					       unsigned long len, int nb)
 {
 	struct sock *sk = chan->data;
@@ -1299,7 +1300,7 @@
 	int err;
 
 	l2cap_chan_unlock(chan);
-	skb = bt_skb_send_alloc(sk, len, nb, &err);
+	skb = bt_skb_send_alloc(sk, hdr_len + len, nb, &err);
 	l2cap_chan_lock(chan);
 
 	if (!skb)