[openib-general] [PATCH 3/3] iWARP CM

[Sean Hefty]

Caitlin Bestler wrote:
>>>+int iw_cm_accept(struct iw_cm_id *cm_id,
>>>+		 const void *private_data,
>>>+		 u8 private_data_len)
>>>+{

{snip}

>>>+	spin_lock_irqsave(&iwcm_id_priv->lock, flags);
>>>+	switch (cm_id->state) {
>>>+	case IW_CM_STATE_CONN_RECV:
>>>+		spin_unlock_irqrestore(&iwcm_id_priv->lock, flags);
>>>+		ret = cm_id->device->iwcm->accept(cm_id, private_data, +
> 
> 
>>>private_data_len); +		if (ret == 0) {
>>>+			struct iw_cm_event event;
>>>+			event.event = IW_CM_EVENT_ESTABLISHED;
>>>+			event.provider_id = cm_id->provider_id;
>>>+			event.status = 0;
>>>+			event.local_addr = cm_id->local_addr;
>>>+			event.remote_addr = cm_id->remote_addr;
>>
>>If the cm_id contains the provider_id, local_addr, and
>>remote_addr, does it need to be returned as part of the event?
>>
> 
> It should be possible to create the cm_id to listen for all
> IP addresses that the Ethernet device is capable of accepting.
> That would mean that event.local_Addr should be set from the
> actual packet.

The cm_id in this case is a new one spawned as a result of receiving a 
connection request associated with a listen.  The cm_id address information 
comes from an event reported by some lower-level entity.  I'd need to read back 
through more of the code to know where the data comes from, but from an actual 
packet is likely.

The question is that if the cm_id contains a copy of the address, then it's not 
necessary to also report the same data in the event structure.

> This relates back to the question on whether a port has
> more than one address. It depends on your definition of a
> port.  If the definition of a port is a netdevice then it
> is only necessary to provide one of the addresses. Existing
> techniques allow fetching the other aliases that refer to
> the same ethernet interface. There is no reason for the RDMA
> drivers to take on the complexity of reporting all possible
> IP addresses when the answer already exists in for non-RDMA.

My comment was in reference to the iwcm_port structure, which maps to a physical 
port on the device.  I can't say that I understand the use of the local_addr 
field in that structure.

- Sean