HEADS UP: destroy_dev_sched() KPI in the tree

[Danny Braniss]

> Today, I got re@ permission and committed the destroy_dev_sched() KPI
> into the tree. As suggested by Nate Lawson, destroy_dev() tries to
> auto-detect "devdrn" deadlock condition and transforms destroy_dev()
> from d_close() csw method into destroy_dev_sched(). I together with
> Peter Holm tried to test the change as thoroughly as possible.
> 
> The obvious problematic area are the races between device driver
> module unload and destroy_dev_sched(). At least smb(4) definitely
> has that race that shall be worked around by draining events with
> drain_dev_clone_events() and destroy_dev_drain(&cdevsw); see snp(4)
> change for example.
> 
> Please, report issues caused by the patch to the list with me Cc:ed.
> Change of autodetection of deadlock in destroy_dev() was made in separate
> commit for ease of reverting.

and today I got a chance to check it, and it works for me (iscsi_initiator).

danny