System hang issue during hibernation resume due to del_gendisk

[Keith Busch]

On Tue, 11 Nov 2014, Keith Busch wrote:
> I knew calling del_gendisk from resume wouldn't work, which is why it's
> done in a work queue, and removed in another thread if the device is
> gone. That's still not okay?

I can see how it might not be okay if the driver does not include
this patch:

http://git.infradead.org/users/willy/linux-nvme.git/commit/74bae7e0dd70f3eee05d577d3d25fbcd54af4228