i40e: Add rx_missed_errors for buffer exhaustion

As the comment in struct rtnl_link_stats64, rx_dropped should not
include packets dropped by the device due to buffer exhaustion.
They are counted in rx_missed_errors, procfs folds those two counters
together.

Add rx_missed_errors for buffer exhaustion, rx_missed_errors corresponds
to rx_discards, rx_dropped corresponds to rx_discards_other.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Tested-by: Arpana Arland <arpanax.arland@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Author: Yajun Deng

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -245,6 +245,7 @@ static const struct i40e_stats i40e_gstrings_net_stats[] = {
 	I40E_NETDEV_STAT(rx_errors),
 	I40E_NETDEV_STAT(tx_errors),
 	I40E_NETDEV_STAT(rx_dropped),
+	I40E_NETDEV_STAT(rx_missed_errors),
 	I40E_NETDEV_STAT(tx_dropped),
 	I40E_NETDEV_STAT(collisions),
 	I40E_NETDEV_STAT(rx_length_errors),
@@ -321,7 +322,7 @@ static const struct i40e_stats i40e_gstrings_stats[] = {
 	I40E_PF_STAT("port.rx_broadcast", stats.eth.rx_broadcast),
 	I40E_PF_STAT("port.tx_broadcast", stats.eth.tx_broadcast),
 	I40E_PF_STAT("port.tx_errors", stats.eth.tx_errors),
-	I40E_PF_STAT("port.rx_dropped", stats.eth.rx_discards),
+	I40E_PF_STAT("port.rx_discards", stats.eth.rx_discards),
 	I40E_PF_STAT("port.tx_dropped_link_down", stats.tx_dropped_link_down),
 	I40E_PF_STAT("port.rx_crc_errors", stats.crc_errors),
 	I40E_PF_STAT("port.illegal_bytes", stats.illegal_bytes),

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -489,6 +489,7 @@ static void i40e_get_netdev_stats_struct(struct net_device *netdev,
 	stats->tx_dropped	= vsi_stats->tx_dropped;
 	stats->rx_errors	= vsi_stats->rx_errors;
 	stats->rx_dropped	= vsi_stats->rx_dropped;
+	stats->rx_missed_errors	= vsi_stats->rx_missed_errors;
 	stats->rx_crc_errors	= vsi_stats->rx_crc_errors;
 	stats->rx_length_errors	= vsi_stats->rx_length_errors;
 }
@@ -680,17 +681,13 @@ i40e_stats_update_rx_discards(struct i40e_vsi *vsi, struct i40e_hw *hw,
 			      struct i40e_eth_stats *stat_offset,
 			      struct i40e_eth_stats *stat)
 {
-	u64 rx_rdpc, rx_rxerr;
-
 	i40e_stat_update32(hw, I40E_GLV_RDPC(stat_idx), offset_loaded,
-			   &stat_offset->rx_discards, &rx_rdpc);
+			   &stat_offset->rx_discards, &stat->rx_discards);
 	i40e_stat_update64(hw,
 			   I40E_GL_RXERR1H(i40e_compute_pci_to_hw_id(vsi, hw)),
 			   I40E_GL_RXERR1L(i40e_compute_pci_to_hw_id(vsi, hw)),
 			   offset_loaded, &stat_offset->rx_discards_other,
-			   &rx_rxerr);
-
-	stat->rx_discards = rx_rdpc + rx_rxerr;
+			   &stat->rx_discards_other);
 }
 
 /**
@@ -712,9 +709,6 @@ void i40e_update_eth_stats(struct i40e_vsi *vsi)
 	i40e_stat_update32(hw, I40E_GLV_TEPC(stat_idx),
 			   vsi->stat_offsets_loaded,
 			   &oes->tx_errors, &es->tx_errors);
-	i40e_stat_update32(hw, I40E_GLV_RDPC(stat_idx),
-			   vsi->stat_offsets_loaded,
-			   &oes->rx_discards, &es->rx_discards);
 	i40e_stat_update32(hw, I40E_GLV_RUPP(stat_idx),
 			   vsi->stat_offsets_loaded,
 			   &oes->rx_unknown_protocol, &es->rx_unknown_protocol);
@@ -971,8 +965,10 @@ static void i40e_update_vsi_stats(struct i40e_vsi *vsi)
 	ns->tx_errors = es->tx_errors;
 	ons->multicast = oes->rx_multicast;
 	ns->multicast = es->rx_multicast;
-	ons->rx_dropped = oes->rx_discards;
-	ns->rx_dropped = es->rx_discards;
+	ons->rx_dropped = oes->rx_discards_other;
+	ns->rx_dropped = es->rx_discards_other;
+	ons->rx_missed_errors = oes->rx_discards;
+	ns->rx_missed_errors = es->rx_discards;
 	ons->tx_dropped = oes->tx_discards;
 	ns->tx_dropped = es->tx_discards;
 

drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c

@@ -4916,7 +4916,7 @@ int i40e_get_vf_stats(struct net_device *netdev, int vf_id,
 	vf_stats->tx_bytes   = stats->tx_bytes;
 	vf_stats->broadcast  = stats->rx_broadcast;
 	vf_stats->multicast  = stats->rx_multicast;
-	vf_stats->rx_dropped = stats->rx_discards;
+	vf_stats->rx_dropped = stats->rx_discards + stats->rx_discards_other;
 	vf_stats->tx_dropped = stats->tx_discards;
 
 	return 0;