[RFC PATCH net-next 8/9] gve: Account for stopped queues when reading NIC stats

[Shailend Chand <shailend@google.com>]

We now account for the fact that the NIC might send us stats for a
subset of queues. Without this change, gve_get_ethtool_stats might make
an invalid access on the priv->stats_report->stats array.

Signed-off-by: Shailend Chand <shailend@google.com>
---
 drivers/net/ethernet/google/gve/gve_ethtool.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index 299206d15c73..2a451aba8328 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -181,12 +181,17 @@ gve_get_ethtool_stats(struct net_device *netdev,
 					    sizeof(int), GFP_KERNEL);
 	if (!rx_qid_to_stats_idx)
 		return;
+	for (ring = 0; ring < priv->rx_cfg.num_queues; ring++)
+		rx_qid_to_stats_idx[ring] = -1;
 	tx_qid_to_stats_idx = kmalloc_array(num_tx_queues,
 					    sizeof(int), GFP_KERNEL);
 	if (!tx_qid_to_stats_idx) {
 		kfree(rx_qid_to_stats_idx);
 		return;
 	}
+	for (ring = 0; ring < num_tx_queues; ring++)
+		tx_qid_to_stats_idx[ring] = -1;
+
 	for (rx_pkts = 0, rx_bytes = 0, rx_hsplit_pkt = 0,
 	     rx_skb_alloc_fail = 0, rx_buf_alloc_fail = 0,
 	     rx_desc_err_dropped_pkt = 0, rx_hsplit_unsplit_pkt = 0,
@@ -308,11 +313,11 @@ gve_get_ethtool_stats(struct net_device *netdev,
 			data[i++] = rx->rx_copybreak_pkt;
 			data[i++] = rx->rx_copied_pkt;
 			/* stats from NIC */
-			if (skip_nic_stats) {
+			stats_idx = rx_qid_to_stats_idx[ring];
+			if (skip_nic_stats || stats_idx == -1) {
 				/* skip NIC rx stats */
 				i += NIC_RX_STATS_REPORT_NUM;
 			} else {
-				stats_idx = rx_qid_to_stats_idx[ring];
 				for (j = 0; j < NIC_RX_STATS_REPORT_NUM; j++) {
 					u64 value =
 						be64_to_cpu(report_stats[stats_idx + j].value);
@@ -383,11 +388,11 @@ gve_get_ethtool_stats(struct net_device *netdev,
 			data[i++] = gve_tx_load_event_counter(priv, tx);
 			data[i++] = tx->dma_mapping_error;
 			/* stats from NIC */
-			if (skip_nic_stats) {
+			stats_idx = tx_qid_to_stats_idx[ring];
+			if (skip_nic_stats || stats_idx == -1) {
 				/* skip NIC tx stats */
 				i += NIC_TX_STATS_REPORT_NUM;
 			} else {
-				stats_idx = tx_qid_to_stats_idx[ring];
 				for (j = 0; j < NIC_TX_STATS_REPORT_NUM; j++) {
 					u64 value =
 						be64_to_cpu(report_stats[stats_idx + j].value);
-- 
2.44.0.769.g3c40516874-goog