Re: [PATCH] iSeries virtual disk

[Christoph Hellwig <hch@infradead.org>]

> > it to the maximum value and then reset it in a magic even handler?
> > I think that logic needs some clarification.
> 
> The "magic event handler" is synchronous with the probe_disk routine.  I
> agree it is a bit confusing, but, at least I have the comment there about
> the side effects of the probe_disk routine.  Changed slightly.

The code that is in Linus' tree is still b0rked:

 - you set viodasd_max_disk in viodasd_open which looks completely bogus:
    o the value is never used after module_init, and as long as module_init
      and blkdev ->open under BKL they are serialized.
    o even if they weren't you wouldn't ever get an open call for a device
      > viodasd_max_disk
    o that means if you actually got there it would either be the same or
      decreased
    o if it was decreased in parallel to module_init your loop in
      module_init would be totally screwed.
  - now to that loop in module_init:
    o they only thing that it actually archives is that it breaks out of
      the loop if a probe_disk fails - but you could archive that much
      more easier by just returning an error from the probe_disk and
      use a break out of the loop.  The >= MAX_DISKNO check could then
      easily happen on the i used as loop counter.

> > for lowend configurations (remember we have a 32bit dev_t now)
> 
> Can I leave this for now?

It's really awkwards.  And IBM will most likely want lots of disks soon
anyway :)