From 53501706a28c2efd0e11efe16c10187730a6f9ed Mon Sep 17 00:00:00 2001
From: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Date: Wed, 4 Jul 2018 11:14:51 +0300
Subject: [PATCH 2/6] ravb: fix invalid context bug while changing link options
 by ethtool
Git-commit: 05925e52a7d379192a5fdff2c33710f573190ead
Patch-mainline: v4.18-rc6
References: git-fixes

The change fixes sleep in atomic context bug, which is encountered
every time when link settings are changed by ethtool.

Since commit 35b5f6b1a82b ("PHYLIB: Locking fixes for PHY I/O
potentially sleeping") phy_start_aneg() function utilizes a mutex
to serialize changes to phy state, however that helper function is
called in atomic context under a grabbed spinlock, because
phy_start_aneg() is called by phy_ethtool_ksettings_set() and by
replaced phy_ethtool_sset() helpers from phylib.

Now duplex mode setting is enforced in ravb_adjust_link() only, also
now RX/TX is disabled when link is put down or modifications to E-MAC
registers ECMR and GECMR are expected for both cases of checked and
ignored link status pin state from E-MAC interrupt handler.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/renesas/ravb_main.c | 49 ++++++++++----------------------
 1 file changed, 15 insertions(+), 34 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 953213689ac3..3e1b31702db1 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -959,6 +959,13 @@ static void ravb_adjust_link(struct net_device *ndev)
 	struct ravb_private *priv = netdev_priv(ndev);
 	struct phy_device *phydev = ndev->phydev;
 	bool new_state = false;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/* Disable TX and RX right over here, if E-MAC change is ignored */
+	if (priv->no_avb_link)
+		ravb_rcv_snd_disable(ndev);
 
 	if (phydev->link) {
 		if (phydev->duplex != priv->duplex) {
@@ -976,18 +983,21 @@ static void ravb_adjust_link(struct net_device *ndev)
 			ravb_modify(ndev, ECMR, ECMR_TXF, 0);
 			new_state = true;
 			priv->link = phydev->link;
-			if (priv->no_avb_link)
-				ravb_rcv_snd_enable(ndev);
 		}
 	} else if (priv->link) {
 		new_state = true;
 		priv->link = 0;
 		priv->speed = 0;
 		priv->duplex = -1;
-		if (priv->no_avb_link)
-			ravb_rcv_snd_disable(ndev);
 	}
 
+	/* Enable TX and RX right over here, if E-MAC change is ignored */
+	if (priv->no_avb_link && phydev->link)
+		ravb_rcv_snd_enable(ndev);
+
+	mmiowb();
+	spin_unlock_irqrestore(&priv->lock, flags);
+
 	if (new_state && netif_msg_link(priv))
 		phy_print_status(phydev);
 }
@@ -1094,39 +1104,10 @@ static int ravb_get_link_ksettings(struct net_device *ndev,
 static int ravb_set_link_ksettings(struct net_device *ndev,
 				   const struct ethtool_link_ksettings *cmd)
 {
-	struct ravb_private *priv = netdev_priv(ndev);
-	unsigned long flags;
-	int error;
-
 	if (!ndev->phydev)
 		return -ENODEV;
 
-	spin_lock_irqsave(&priv->lock, flags);
-
-	/* Disable TX and RX */
-	ravb_rcv_snd_disable(ndev);
-
-	error = phy_ethtool_ksettings_set(ndev->phydev, cmd);
-	if (error)
-		goto error_exit;
-
-	if (cmd->base.duplex == DUPLEX_FULL)
-		priv->duplex = 1;
-	else
-		priv->duplex = 0;
-
-	ravb_set_duplex(ndev);
-
-error_exit:
-	mdelay(1);
-
-	/* Enable TX and RX */
-	ravb_rcv_snd_enable(ndev);
-
-	mmiowb();
-	spin_unlock_irqrestore(&priv->lock, flags);
-
-	return error;
+	return phy_ethtool_ksettings_set(ndev->phydev, cmd);
 }
 
 static int ravb_nway_reset(struct net_device *ndev)
-- 
2.16.4