Re: [PATCH] Fix aic7xxx del_timer_sync() deadlock

[Jens Axboe <axboe@suse.de>]

On Fri, Feb 27 2004, Jeff Garzik wrote:
> Justin T. Gibbs wrote:
> >1) The mid-layer doesn't correctly handle this situation.  The mid-layer
> >   uses blk_plug_device() to implement this behavior rather than
> >   blk_stop_queue().  The leaves the implementation vulnerable to
> >   any code that does a manual unplug (e.g. the SCSI scan code) or a
> >   blk_run_queues() (e.g. MD) which can alter the duration of the delay.
> 
> 
> hum.
> 
> Long term we definitely want to use blk_{start,stop}_queue().  I had to 
> work on Jens for a little while before he was kind enough to add it :) 
> so let's put it to use.

The only nasty right now is that you cannot unconditionally call
blk_stop_queue(), it requires a manual blk_start_queue() on io
completion which will only happen if io is pending of course. I just got
an idea on how to do that properly, I'll make sure it works in any case.

-- 
Jens Axboe