Re: [linux-iscsi-devel] Re: [PATCH RFC] replace ioctl for sysfs take 2

[James Bottomley <James.Bottomley@SteelEye.com>]

On Mon, 2004-09-06 at 22:46, Mike Christie wrote: 
> In that first target patch you sent it had the target dev's bus set to 
> scsi_bus_type. That caused my confusion as to what the bus was for. I 
> see the new patch with this removed. Nevermind.

er, yes, cut and paste error ... 

> We just needed something to track the driver's scsi_hosts. It was also 
> used becuase we used a struct device_driver to hang setup attributes 
> (non iscsi related attrs needed to setup our driver's devices without an 
> ioctl) off of like scsi_debug (this is why I asked about a single 
> virtual bus for both of us to share).

Ah, OK, I see.  So you mean add a bus to the scsi_host->shost_gendev. 
That's certainly feasible.  With clever matching we could get all LLDs
that wanted this functionality to add a dummy driver which they could
then use to traverse their attached hosts.

> Since we followed the suggestion to do a host per transport endpoint 
> when we rmmod the driver we just need some way to loop over every 
> scsi_host and free them up. We had a linked list of scsi_hosts. 
> Christoph suggested a class or bus instead of the linked list, and had 
> preferred the bus. Now you are suggesting to use a class. It wouldn't be 
> ok to go back to the single host would it? In that case we would not 
> need a class, bus, or linked list?

A host is the analogue of a bus.  In iSCSI that's really the other end
point.  Using abstractions incorrectly (like a single host for the
entire iSCSI system) is bound to end up with problems due to the concept
mismatch.

James