i40e: check vsi ptrs before dumping them

Make sure there really are rings and queues before trying to dump
information in them.
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_debugfs.c

@@ -234,27 +234,34 @@ static ssize_t i40e_dbg_dump_write(struct file *filp,
 			memcpy(p, vsi, len);
 			p += len;
 
+			if (vsi->num_q_vectors) {
 				len = (sizeof(struct i40e_q_vector)
 					* vsi->num_q_vectors);
 				memcpy(p, vsi->q_vectors, len);
 				p += len;
+			}
 
-			len = (sizeof(struct i40e_ring) * vsi->num_queue_pairs);
+			if (vsi->num_queue_pairs) {
+				len = (sizeof(struct i40e_ring) *
+				      vsi->num_queue_pairs);
 				memcpy(p, vsi->tx_rings, len);
 				p += len;
 				memcpy(p, vsi->rx_rings, len);
 				p += len;
+			}
 
-			for (i = 0; i < vsi->num_queue_pairs; i++) {
+			if (vsi->tx_rings[0]) {
 				len = sizeof(struct i40e_tx_buffer);
+				for (i = 0; i < vsi->num_queue_pairs; i++) {
 					memcpy(p, vsi->tx_rings[i]->tx_bi, len);
 					p += len;
 				}
-			for (i = 0; i < vsi->num_queue_pairs; i++) {
 				len = sizeof(struct i40e_rx_buffer);
+				for (i = 0; i < vsi->num_queue_pairs; i++) {
 					memcpy(p, vsi->rx_rings[i]->rx_bi, len);
 					p += len;
 				}
+			}
 
 			/* macvlan filter list */
 			len = sizeof(struct i40e_mac_filter);