[PATCH 4.14 148/217] ravb: fix invalid context bug while changing link options by ethtool

Greg Kroah-Hartman
2018-08-23T08:30:21Z

From: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>

[ Upstream commit 05925e52a7d379192a5fdff2c33710f573190ead ]

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: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/renesas/ravb_main.c | 49 +++++++++----------------------
1 file changed, 15 insertions(+), 34 deletions(-)

--- 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_
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_
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(struc
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)