net/mlx5e: Introducing new statistics rwlock

Introduce a new read/write lock that will protect statistics gathering from
netdev channels configuration changes.
e.g. when channels are being replaced (increase/decrease number of rings)
prevent statistic gathering (ndo_get_stats64) to read the statistics of
in-active channels (channels that are being closed).

Plus update channels software statistics on the fly when calling
ndo_get_stats64, and remove it from stats periodic work.

Fixes: 9218b44 ("net/mlx5e: Statistics handling refactoring")
Signed-off-by: Shalom Lagziel <shaloml@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -771,6 +771,8 @@ struct mlx5e_priv {
 	struct mutex               state_lock; /* Protects Interface state */
 	struct mlx5e_rq            drop_rq;
 
+	rwlock_t                   stats_lock; /* Protects channels SW stats updates */
+	bool                       channels_active;
 	struct mlx5e_channels      channels;
 	u32                        tisn[MLX5E_MAX_NUM_TC];
 	struct mlx5e_rqt           indir_rqt;

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -2658,6 +2658,9 @@ void mlx5e_activate_priv_channels(struct mlx5e_priv *priv)
 
 	mlx5e_build_channels_tx_maps(priv);
 	mlx5e_activate_channels(&priv->channels);
+	write_lock(&priv->stats_lock);
+	priv->channels_active = true;
+	write_unlock(&priv->stats_lock);
 	netif_tx_start_all_queues(priv->netdev);
 
 	if (MLX5_VPORT_MANAGER(priv->mdev))
@@ -2679,6 +2682,9 @@ void mlx5e_deactivate_priv_channels(struct mlx5e_priv *priv)
 	 */
 	netif_tx_stop_all_queues(priv->netdev);
 	netif_tx_disable(priv->netdev);
+	write_lock(&priv->stats_lock);
+	priv->channels_active = false;
+	write_unlock(&priv->stats_lock);
 	mlx5e_deactivate_channels(&priv->channels);
 }
 
@@ -3223,6 +3229,7 @@ mlx5e_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats)
 		stats->tx_packets = PPORT_802_3_GET(pstats, a_frames_transmitted_ok);
 		stats->tx_bytes   = PPORT_802_3_GET(pstats, a_octets_transmitted_ok);
 	} else {
+		mlx5e_grp_sw_update_stats(priv);
 		stats->rx_packets = sstats->rx_packets;
 		stats->rx_bytes   = sstats->rx_bytes;
 		stats->tx_packets = sstats->tx_packets;
@@ -4248,6 +4255,7 @@ static void mlx5e_build_nic_netdev_priv(struct mlx5_core_dev *mdev,
 			       profile->max_nch(mdev), netdev->mtu);
 
 	mutex_init(&priv->state_lock);
+	rwlock_init(&priv->stats_lock);
 
 	INIT_WORK(&priv->update_carrier_work, mlx5e_update_carrier_work);
 	INIT_WORK(&priv->set_rx_mode_work, mlx5e_set_rx_mode_work);

drivers/net/ethernet/mellanox/mlx5/core/en_rep.c

@@ -130,6 +130,10 @@ static void mlx5e_rep_update_sw_counters(struct mlx5e_priv *priv)
 	struct mlx5e_sq_stats *sq_stats;
 	int i, j;
 
+	read_lock(&priv->stats_lock);
+	if (!priv->channels_active)
+	        goto out;
+
 	memset(s, 0, sizeof(*s));
 	for (i = 0; i < priv->channels.num; i++) {
 		struct mlx5e_channel *c = priv->channels.c[i];
@@ -146,12 +150,8 @@ static void mlx5e_rep_update_sw_counters(struct mlx5e_priv *priv)
 			s->tx_bytes		+= sq_stats->bytes;
 		}
 	}
-}
-
-static void mlx5e_rep_update_stats(struct mlx5e_priv *priv)
-{
-	mlx5e_rep_update_sw_counters(priv);
-	mlx5e_rep_update_hw_counters(priv);
+out:
+	read_unlock(&priv->stats_lock);
 }
 
 static void mlx5e_rep_get_ethtool_stats(struct net_device *dev,
@@ -871,6 +871,8 @@ mlx5e_get_sw_stats64(const struct net_device *dev,
 	struct mlx5e_priv *priv = netdev_priv(dev);
 	struct mlx5e_sw_stats *sstats = &priv->stats.sw;
 
+	mlx5e_rep_update_sw_counters(priv);
+
 	stats->rx_packets = sstats->rx_packets;
 	stats->rx_bytes   = sstats->rx_bytes;
 	stats->tx_packets = sstats->tx_packets;
@@ -1046,7 +1048,7 @@ static const struct mlx5e_profile mlx5e_rep_profile = {
 	.cleanup_rx		= mlx5e_cleanup_rep_rx,
 	.init_tx		= mlx5e_init_rep_tx,
 	.cleanup_tx		= mlx5e_cleanup_nic_tx,
-	.update_stats           = mlx5e_rep_update_stats,
+	.update_stats           = mlx5e_rep_update_hw_counters,
 	.max_nch		= mlx5e_get_rep_max_num_channels,
 	.update_carrier		= NULL,
 	.rx_handlers.handle_rx_cqe       = mlx5e_handle_rx_cqe_rep,

drivers/net/ethernet/mellanox/mlx5/core/en_stats.c

@@ -108,7 +108,7 @@ static int mlx5e_grp_sw_fill_stats(struct mlx5e_priv *priv, u64 *data, int idx)
 	return idx;
 }
 
-static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv)
+void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv)
 {
 	struct mlx5e_sw_stats temp, *s = &temp;
 	struct mlx5e_rq_stats *rq_stats;
@@ -117,6 +117,9 @@ static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv)
 	int i, j;
 
 	memset(s, 0, sizeof(*s));
+	read_lock(&priv->stats_lock);
+	if (!priv->channels_active)
+		goto out;
 	for (i = 0; i < priv->channels.num; i++) {
 		struct mlx5e_channel *c = priv->channels.c[i];
 
@@ -175,6 +178,8 @@ static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv)
 	}
 
 	memcpy(&priv->stats.sw, s, sizeof(*s));
+out:
+	read_unlock(&priv->stats_lock);
 }
 
 static const struct counter_desc q_stats_desc[] = {
@@ -1224,7 +1229,6 @@ const struct mlx5e_stats_grp mlx5e_stats_grps[] = {
 		.get_num_stats = mlx5e_grp_sw_get_num_stats,
 		.fill_strings = mlx5e_grp_sw_fill_strings,
 		.fill_stats = mlx5e_grp_sw_fill_stats,
-		.update_stats_mask = MLX5E_NDO_UPDATE_STATS,
 		.update_stats = mlx5e_grp_sw_update_stats,
 	},
 	{

drivers/net/ethernet/mellanox/mlx5/core/en_stats.h

@@ -239,4 +239,6 @@ struct mlx5e_stats_grp {
 extern const struct mlx5e_stats_grp mlx5e_stats_grps[];
 extern const int mlx5e_num_stats_grps;
 
+void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv);
+
 #endif /* __MLX5_EN_STATS_H__ */