Re: [PATCH 4/4] bnx2i: Add bnx2i iSCSI driver.

[Mike Christie <michaelc@cs.wisc.edu>]

Michael Chan wrote:
> On Wed, 2009-05-06 at 09:48 -0700, Mike Christie wrote:
>>> +
>>> +/**
>>> + * bnx2i_nl_mesg_recv -
>>> + * @buf:	pointer to buffer containing vendor specific message
>>> + * @buf:	buffer length
>>> + *
>>> + */
>>> +static int bnx2i_nl_mesg_recv(struct Scsi_Host *shost, uint16_t priv_op,
>>> +			      int status, char *buf, int buflen)
>>> +{
>>> +	struct bnx2i_hba *hba = iscsi_host_priv(shost);
>>> +
>>> +	switch (priv_op) {
>>> +	case NX2_UIO_UEVENT_NEIGH_LOOKUP:
>>> +	default:
>>> +		/* handle by cnic driver */
>>> +		hba->cnic->nl_priv_msg_recv(hba->cnic, priv_op, buf, buflen);
>>> +		break;
>>> +	}
>>> +
>>> +	return buflen;
>>> +}
>> I think I was wrong with one of the comments I gave you.
>>
>> It seems like we have two iscsi net config models.
>>
>> 1. qla4xxx and Server Engines type of setup where the driver just tells 
>> the card to use some ip or do dhcp and some other net settings and it 
>> does all the net magic. The iscsi driver does not have to worry about 
>> anything like the dhcp process or arp. It only passes down the setup values.
>>
>> 2. cxgb3i and bnx2i type of model where kernel or userspace code is 
>> needed to execute many net operations.
>> - Right now, cxgb3i sort of cheated :) and only supports static IPs. It 
>> currently uses the iscsi set param interface to do this.
>>
>> - bnx2i wants to add more complicated features and is going to do them 
>> in userspace. It us using the private messages that were added in the 
>> previous patch.
>>
>>
>> I think cxgb3i is one day going to want to support the same features 
>> bnx2i does. If that is right, then should we just make the NX2_UIO 
>> events common iscsi events, and hook cxb3i in? It would not use the 
>> iscsi set param interface at all and would work just like bnx2i. Is that 
>> possible? What about future drivers? Are done making iscsi cards and 
>> drivers. If so, thank goodness :)  If not then maybe we want to consider 
>> some future driver using the #2 module and possibly using this.
>>
>> If cxgb3i is really only going to support static ip setup and we think 
>> that bnx2i is going to be unique on how it sets up the network then I 
>> NX2_UIO private events are fine. Or is this a case of we are thinking 
>> that iscsi hardware people are creating crazy interfaces so there is no 
>> why to predict what they are going to do so there is no point in trying 
>> to design for them.
> 
> If there is any possibility that cxgb3i will use something similar to
> bnx2i, I think we can change the message to a standard one and make the
> message structure somewhat more generic.  We'll probably still need a
> private area in the message for hardware or vendor specific information.
> 

Ok sounds good to me.