Re: block devices don't work without plugging in 2.4.3

["Peter T. Breuer" <ptb@it.uc3m.es>]

"A month of sundays ago Jens Axboe wrote:"
> On Thu, Apr 19 2001, Peter T. Breuer wrote:
> > So the consensus is that I should enable plugging while the plugging
> > function is still here and do nothing when it goes? I must say I don't
> > think it should really "go", since that means I have to add a no-op
> > macro to replace it, and I don't like #ifdefs. 
> 
> The moral would be that you should never do anything. You didn't enable
> plugging with blk_queue_pluggable, only disabled it by using a noop
> plug.

I was thinking about what has to be done to allow my code to compile in
older kernels. I _believe_ (I may be mistaken) that I had to _explicitly_
disable plugging at some stage. Probably in 2.2. and possibly in 2.4.0.

On that basis, I do need a plug_fn and a blk_queue_pluggable for
compilation against those kernels, and these should both be macro'ed to
oblivion in the newest kernels. No? 

Apologies for the continued vagueness. There are a lot of states to
consider: two machine states (plugged/not plugged) and several code
states (whatever had to be done when to cause what).

Peter