Re: can we increase the send buffer size of rfcomm socket?

[Marcel Holtmann <marcel@holtmann.org>]

Hi Zhu,

> We tried to write a 64k data to rfcomm socket, but it will break
> before sending all of the data out. The problem is in function
> rfcomm_sock_sendmsg() in net/bluetooth/rfcomm/sock.c, it breaks after
> calling sock_alloc_send_skb().
> 
> static int rfcomm_sock_sendmsg(...)
> {
>    ...
> 		skb = sock_alloc_send_skb(sk, size + RFCOMM_SKB_RESERVE,
> 				msg->msg_flags & MSG_DONTWAIT, &err);
> 		if (!skb)
> 			break;
>    ...
> }
> 
> Looks the send buffer is not adequate. Then I increased the send
> buffer size in function rfcomm_sock_alloc(),  build kernel and try
> again, this time the sendmsg can complete sending all the data.
> 
> Can we use the setsockopt() method to change the socket's send/receive
> buffer size, just like the usual  tcp/ip socket?

yes we can. Send a patch for it and I am going to review it.

Regards

Marcel