scsi: fnic: do not queue commands during fwreset

When a link is going down the driver will be calling fnic_cleanup_io(),
which will traverse all commands and calling 'done' for each found command.
While the traversal is handled under the host_lock, calling 'done' happens
after the host_lock is being dropped.

As fnic_queuecommand_lck() is being called with the host_lock held, it
might well be that it will pick the command being selected for abortion
from the above routine and enqueue it for sending, but then 'done' is being
called on that very command from the above routine.

Which of course confuses the hell out of the scsi midlayer.

So fix this by not queueing commands when fnic_cleanup_io is active.

Link: https://lore.kernel.org/r/20200116102053.62755-1-hare@suse.de
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fnic/fnic_scsi.c

@@ -439,6 +439,9 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_
 	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_IO_BLOCKED)))
 		return SCSI_MLQUEUE_HOST_BUSY;
 
+	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_FWRESET)))
+		return SCSI_MLQUEUE_HOST_BUSY;
+
 	rport = starget_to_rport(scsi_target(sc->device));
 	if (!rport) {
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,