libiscsi: return new error code when nop times out

When a iscsi nop as ping timedout we were failing with the
common connection error code, ISCSI_ERR_CONN_FAILED. This
patch adds a new error code for this problem so can properly
track/distinguish in userspace.

Signed-off-by: Mike Christie <[e-mail]>
Acked-by: Vikas Chaudhary <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>

drivers/scsi/libiscsi.c

···
 				  conn->ping_timeout, conn->recv_timeout,
 				  last_recv, conn->last_ping, jiffies);
 		spin_unlock(&session->frwd_lock);
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		iscsi_conn_failure(conn, ISCSI_ERR_NOP_TIMEDOUT);
 		return;
 	}
 

include/scsi/iscsi_if.h

···
 	ISCSI_ERR_XMIT_FAILED		= ISCSI_ERR_BASE + 19,
 	ISCSI_ERR_TCP_CONN_CLOSE	= ISCSI_ERR_BASE + 20,
 	ISCSI_ERR_SCSI_EH_SESSION_RST	= ISCSI_ERR_BASE + 21,
+	ISCSI_ERR_NOP_TIMEDOUT		= ISCSI_ERR_BASE + 22,
 };
 
 /*