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

[Mike Christie <mikenc@us.ibm.com>]

James Bottomley wrote:
> On Tue, 2004-09-07 at 18:40, Mike Christie wrote:
> 
>>>Possibly, but only if the way its handled would be the same on all iscsi
>>>initiator drivers.  Otherwise, if it's specific to the driver
>>>implementation, it would be in hostdata. 
>>
>>Yes, ok. That is what I am striving for. By us hanging things like 
>>target name on the target instead of on the scsi device or scsi host 
>>will help us conform to other HW iscsi drivers.
> 
> 
> You're thinking of the qlogic one?  They have an entire network stack
> onboard and they do have resource restrictions per card.  A virtual
> driver doesn't.
> 

I just meant that I am trying to get the iscsi transport class to have 
common code across virtual and non virtual drivers. I was not striving 
for virtual and non-virtual to alloc hosts alike. I was the one that 
converted the iscsi driver to host per session and caused this mess :(

The reason I kept asking below is becuase I misunderstood the resource 
comment, and was unsure if I did the right thing and was supposed to 
convert the driver back to a single host.

>>  Regardless, you'd still have
>>
>>>one host per one of these entities.
>>
>>One host per I_T nexus/session? But I thought the only reason against 
>>using a single host for all nexii (ignoring the port/channel 
>>discussion), was that the driver would need its own refcounting.
> 
> 
> It's not just refcounting, it's resource management.  It seems to me,
> given that you can allocate resources per connection that per connection
> is the most efficient way to manage them.
> 
>>If the target has some place for driver target data (with the common 
>>iscsi code going in the appropriate transport class stucts) couldn't we 
>>just do sometihng similar to how a scsi_device has the hostdata pointers 
>>and drivers seem to assume when slave_destroy is called they can just 
>>free what was allocated in slave_alloc. And when the driver does its 
>>final scsi_host_put it assumes the hostdata will get freed when all the 
>>handles are released. If the midlayer could provide any similar lifetime 
>>management functionality for targets the iscsi driver would not need any 
>>private structures that are refcounted internally since everything could 
>>fall under the host, device, or target's managemnet.
> 
> 
> Theoretically, I suppose.  The mid-layer really prefers to think in
> terms of hosts and devices.  It doesn't really have much use for
> targets.
> 
> James
> 
> 
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