nvme: cancel pending I/O if nvme controller is in terminal state

nvme: cancel pending I/O if nvme controller is in terminal state

While I/O is running, if the pci bus error occurs then
in-flight I/O can not complete. Worst, if at this time,
user (logically) hot-unplug the nvme disk then the
nvme_remove() code path can't forward progress until
in-flight I/O is cancelled. So these sequence of events
may potentially hang hot-unplug code path indefinitely.
This patch helps cancel the pending/in-flight I/O from the
nvme request timeout handler in case the nvme controller
is in the terminal (DEAD/DELETING/DELETING_NOIO) state and
that helps nvme_remove() code path forward progress and
finish successfully.

Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Nilay Shroff <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Signed-off-by: Keith Busch <[email protected]>