From: Eran Ben Elisha <eranbe@mellanox.com>
Date: Wed, 13 Dec 2017 18:12:11 +0200
Subject: net/mlx4_en: Fill all counters under one call of stats lock
Patch-mainline: v4.15-rc4
Git-commit: 5a1647c391ba543a77a400dddf89053ec5c2b7a4
References: bsc#1046299 FATE#322947

Before this patch, the stats_lock was acquired twice. In between the
locks Driver sent command to gather some more statistics (per priority
and counter statistics). If the stats lock was acquired by get
statistics NDO in between we would have report out of sync counters.

Fix this by collecting all stats from Firmware in advance and then
fill the Software structs under one lock.

Fixes: 0b131561a7d6 ("net/mlx4_en: Add Flow control statistics display via ethtool")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx4/en_port.c |   57 ++++++++++++++-------------
 1 file changed, 31 insertions(+), 26 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_port.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_port.c
@@ -188,7 +188,7 @@ int mlx4_en_DUMP_ETH_STATS(struct mlx4_e
 	struct net_device *dev = mdev->pndev[port];
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct net_device_stats *stats = &dev->stats;
-	struct mlx4_cmd_mailbox *mailbox;
+	struct mlx4_cmd_mailbox *mailbox, *mailbox_priority;
 	u64 in_mod = reset << 8 | port;
 	int err;
 	int i, counter_index;
@@ -198,6 +198,13 @@ int mlx4_en_DUMP_ETH_STATS(struct mlx4_e
 	mailbox = mlx4_alloc_cmd_mailbox(mdev->dev);
 	if (IS_ERR(mailbox))
 		return PTR_ERR(mailbox);
+
+	mailbox_priority = mlx4_alloc_cmd_mailbox(mdev->dev);
+	if (IS_ERR(mailbox_priority)) {
+		mlx4_free_cmd_mailbox(mdev->dev, mailbox);
+		return PTR_ERR(mailbox_priority);
+	}
+
 	err = mlx4_cmd_box(mdev->dev, 0, mailbox->dma, in_mod, 0,
 			   MLX4_CMD_DUMP_ETH_STATS, MLX4_CMD_TIME_CLASS_B,
 			   MLX4_CMD_NATIVE);
@@ -206,6 +213,28 @@ int mlx4_en_DUMP_ETH_STATS(struct mlx4_e
 
 	mlx4_en_stats = mailbox->buf;
 
+	memset(&tmp_counter_stats, 0, sizeof(tmp_counter_stats));
+	counter_index = mlx4_get_default_counter_index(mdev->dev, port);
+	err = mlx4_get_counter_stats(mdev->dev, counter_index,
+				     &tmp_counter_stats, reset);
+
+	/* 0xffs indicates invalid value */
+	memset(mailbox_priority->buf, 0xff,
+	       sizeof(*flowstats) * MLX4_NUM_PRIORITIES);
+
+	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_FLOWSTATS_EN) {
+		memset(mailbox_priority->buf, 0,
+		       sizeof(*flowstats) * MLX4_NUM_PRIORITIES);
+		err = mlx4_cmd_box(mdev->dev, 0, mailbox_priority->dma,
+				   in_mod | MLX4_DUMP_ETH_STATS_FLOW_CONTROL,
+				   0, MLX4_CMD_DUMP_ETH_STATS,
+				   MLX4_CMD_TIME_CLASS_B, MLX4_CMD_NATIVE);
+		if (err)
+			goto out;
+	}
+
+	flowstats = mailbox_priority->buf;
+
 	spin_lock_bh(&priv->stats_lock);
 
 	mlx4_en_fold_software_stats(dev);
@@ -345,31 +374,6 @@ int mlx4_en_DUMP_ETH_STATS(struct mlx4_e
 	priv->pkstats.tx_prio[8][0] = be64_to_cpu(mlx4_en_stats->TTOT_novlan);
 	priv->pkstats.tx_prio[8][1] = be64_to_cpu(mlx4_en_stats->TOCT_novlan);
 
-	spin_unlock_bh(&priv->stats_lock);
-
-	memset(&tmp_counter_stats, 0, sizeof(tmp_counter_stats));
-	counter_index = mlx4_get_default_counter_index(mdev->dev, port);
-	err = mlx4_get_counter_stats(mdev->dev, counter_index,
-				     &tmp_counter_stats, reset);
-
-	/* 0xffs indicates invalid value */
-	memset(mailbox->buf, 0xff, sizeof(*flowstats) * MLX4_NUM_PRIORITIES);
-
-	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_FLOWSTATS_EN) {
-		memset(mailbox->buf, 0,
-		       sizeof(*flowstats) * MLX4_NUM_PRIORITIES);
-		err = mlx4_cmd_box(mdev->dev, 0, mailbox->dma,
-				   in_mod | MLX4_DUMP_ETH_STATS_FLOW_CONTROL,
-				   0, MLX4_CMD_DUMP_ETH_STATS,
-				   MLX4_CMD_TIME_CLASS_B, MLX4_CMD_NATIVE);
-		if (err)
-			goto out;
-	}
-
-	flowstats = mailbox->buf;
-
-	spin_lock_bh(&priv->stats_lock);
-
 	if (tmp_counter_stats.counter_mode == 0) {
 		priv->pf_stats.rx_bytes   = be64_to_cpu(tmp_counter_stats.rx_bytes);
 		priv->pf_stats.tx_bytes   = be64_to_cpu(tmp_counter_stats.tx_bytes);
@@ -410,6 +414,7 @@ int mlx4_en_DUMP_ETH_STATS(struct mlx4_e
 
 out:
 	mlx4_free_cmd_mailbox(mdev->dev, mailbox);
+	mlx4_free_cmd_mailbox(mdev->dev, mailbox_priority);
 	return err;
 }