[PATCH] nvme: fix hang in remove path

[Rakesh Pandit]

On Sun, Jun 04, 2017 at 06:24:09PM +0300, Sagi Grimberg wrote:
> 
> > It would make sense to still add:
> > 
> > if (ctrl->state == NVME_CTRL_DELETING || ctrl->state == NVME_CTRL_DEAD)
> > 	return
> > 
> > inside nvme_configure_apst at the top irrespective of this change.
> 
> I'm not sure what is the value given that it is taken care of in
> .queue_rq?

We would avoid getting error message which says: "failed to set APST
feature 7".  Why an error if controller is already under reset.

Note 7 here is NVME_SC_ABORT_REQ.  Also we would avoid walking through
all power states inside the nvme_configure_apst as
nvme_set_latency_tolerance was called with value
PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1) which sets
ctrl->ps_max_latency_us to U64_MAX and tries to send a sync command
which of course fails with error message.