netdev - [net-next 06/14] net/mlx5e: Allow mlx5e_safe_switch

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Date:   Fri, 16 Apr 2021 11:54:22 -0700
From:   Saeed Mahameed <saeed@...nel.org>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Tariq Toukan <tariqt@...dia.com>, netdev@...r.kernel.org,
        Maxim Mikityanskiy <maximmi@...lanox.com>,
        Saeed Mahameed <saeedm@...dia.com>
Subject: [net-next 06/14] net/mlx5e: Allow mlx5e_safe_switch_channels to work with channels closed

From: Maxim Mikityanskiy <maximmi@...lanox.com>

mlx5e_safe_switch_channels is used to modify channel parameters and/or
hardware configuration in a safe way, so that if anything goes wrong,
everything reverts to the old configuration and remains in a consistent
state.

However, this function only works when the channels are open. When the
caller needs to modify some parameters, first it has to check that the
channels are open, otherwise it has to assign parameters directly, and
such boilerplate repeats in many different places.

This commit prepares for the refactoring of such places by allowing
mlx5e_safe_switch_channels to work when the channels are closed. In this
case it will assign the new parameters and run the preactivate hook.

Signed-off-by: Maxim Mikityanskiy <maximmi@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 40 +++++++++++++------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index df4959e46f27..cb88d7239db6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -2852,12 +2852,16 @@ static int mlx5e_switch_priv_channels(struct mlx5e_priv *priv,
 	struct net_device *netdev = priv->netdev;
 	struct mlx5e_channels old_chs;
 	int carrier_ok;
+	bool opened;
 	int err = 0;
 
-	carrier_ok = netif_carrier_ok(netdev);
-	netif_carrier_off(netdev);
+	opened = test_bit(MLX5E_STATE_OPENED, &priv->state);
+	if (opened) {
+		carrier_ok = netif_carrier_ok(netdev);
+		netif_carrier_off(netdev);
 
-	mlx5e_deactivate_priv_channels(priv);
+		mlx5e_deactivate_priv_channels(priv);
+	}
 
 	old_chs = priv->channels;
 	priv->channels = *new_chs;
@@ -2873,15 +2877,19 @@ static int mlx5e_switch_priv_channels(struct mlx5e_priv *priv,
 		}
 	}
 
-	mlx5e_close_channels(&old_chs);
-	priv->profile->update_rx(priv);
+	if (opened) {
+		mlx5e_close_channels(&old_chs);
+		priv->profile->update_rx(priv);
+	}
 
 out:
-	mlx5e_activate_priv_channels(priv);
+	if (opened) {
+		mlx5e_activate_priv_channels(priv);
 
-	/* return carrier back if needed */
-	if (carrier_ok)
-		netif_carrier_on(netdev);
+		/* return carrier back if needed */
+		if (carrier_ok)
+			netif_carrier_on(netdev);
+	}
 
 	return err;
 }
@@ -2891,11 +2899,16 @@ int mlx5e_safe_switch_channels(struct mlx5e_priv *priv,
 			       mlx5e_fp_preactivate preactivate,
 			       void *context)
 {
+	bool opened;
 	int err;
 
-	err = mlx5e_open_channels(priv, new_chs);
-	if (err)
-		return err;
+	opened = test_bit(MLX5E_STATE_OPENED, &priv->state);
+
+	if (opened) {
+		err = mlx5e_open_channels(priv, new_chs);
+		if (err)
+			return err;
+	}
 
 	err = mlx5e_switch_priv_channels(priv, new_chs, preactivate, context);
 	if (err)
@@ -2904,7 +2917,8 @@ int mlx5e_safe_switch_channels(struct mlx5e_priv *priv,
 	return 0;
 
 err_close:
-	mlx5e_close_channels(new_chs);
+	if (opened)
+		mlx5e_close_channels(new_chs);
 
 	return err;
 }
-- 
2.30.2