Re: [PATCH] get rid of ->finish method for highlevel drivers

[Christoph Hellwig <hch@lst.de>]

On Wed, Oct 23, 2002 at 09:16:49AM -0500, James Bottomley wrote:
> This is really exposing our whole detect init attach finish slave_attach mess 
> which Christoph was trying to clean up.
> 
> What happens now (after Christoph's removal of finish) is:
> 
> 1) call detect to see if anyone will attach.  If yes, call slave attach (we 
> adjust the queue depth here if wanted)
> 2) call init (if not inited---done once per upper level driver) --- init is 
> supposed to be for first init of the SCSI upper level device driver to 
> allocate inital resources, so we already have detect called befor init.

Well, I'm working on removing ->init.  With the patch posted yersterday
only sg.c and osst.c are left implementing it.

> 3) call attach but release the commandblocks if sdev->attached comes back zero.
> 
> -> attached, by the way is a semaphore because we can have more than one upper 
> level attachment.  This exposes nicely in the rather icky algorithm of 
> scsi_get_request_dev() which is used to find which upper level driver should 
> process the request in the request function.
> 
> It looks like what we want to have happen is:
> 
> 1) init first
>
> 
> 2) detect is currently superfluous (there will probably be a future time when 
> we need a separate detect for lazy attachment---devices don't attach and 
> consume resources until the operator so instructs)
> 4) call build commandblocks to get a single working command
> 5) attach
> 6) if anything attached do the slave attach or cmd_per_lun adjustment.  If 
> not, release the command blocks.

Completly agreed with that.