[SCSI] fc_transport: Check portstates before invoking target scan

When a target scan is initiated from sysfs, we should check the
portstate prior to invoke scsi_scan_target().
Otherwise scsi_scan_target() might oops as the rport might already
been removed from the scsi host and the traversal from the rport to
the scsi_host in scsi_scan_target() will fail.
Also the portstate already told us that communication with the target
has failed, so it's quite pointless to try.

Signed-off-by: Hannes Reinecke <[e-mail]>
Cc: James Smart <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/scsi_transport_fc.c

···
 		if (rport->scsi_target_id == -1)
 			continue;
 
+		if (rport->port_state != FC_PORTSTATE_ONLINE)
+			continue;
+
 		if ((channel == SCAN_WILD_CARD || channel == rport->channel) &&
 		    (id == SCAN_WILD_CARD || id == rport->scsi_target_id)) {
 			scsi_scan_target(&rport->dev, rport->channel,