sh_eth: fix invalid context bug while changing link options by ethtool

[ Upstream commit 5cb3f52a11e18628fc4bee76dd14b1f0b76349de ]

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 sh_eth_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.

For reference the change is a partial rework of commit 1e1b812bbe10
("sh_eth: fix handling of no LINK signal").

Fixes: dc19e4e5e02f ("sh: sh_eth: Add support ethtool")
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>

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 22adaa169ddd0896be17e6304252879600ba29d8..abfb9faadbc40b10a36dfba58d2801e603961bcb 100644 (file)
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1821,8 +1821,15 @@ static void sh_eth_adjust_link(struct net_device *ndev)
 {
        struct sh_eth_private *mdp = netdev_priv(ndev);
        struct phy_device *phydev = ndev->phydev;
+       unsigned long flags;
        int new_state = 0;
 
+       spin_lock_irqsave(&mdp->lock, flags);
+
+       /* Disable TX and RX right over here, if E-MAC change is ignored */
+       if (mdp->cd->no_psr || mdp->no_ether_link)
+               sh_eth_rcv_snd_disable(ndev);
+
        if (phydev->link) {
                if (phydev->duplex != mdp->duplex) {
                        new_state = 1;
@@ -1841,18 +1848,21 @@ static void sh_eth_adjust_link(struct net_device *ndev)
                        sh_eth_modify(ndev, ECMR, ECMR_TXF, 0);
                        new_state = 1;
                        mdp->link = phydev->link;
-                       if (mdp->cd->no_psr || mdp->no_ether_link)
-                               sh_eth_rcv_snd_enable(ndev);
                }
        } else if (mdp->link) {
                new_state = 1;
                mdp->link = 0;
                mdp->speed = 0;
                mdp->duplex = -1;
-               if (mdp->cd->no_psr || mdp->no_ether_link)
-                       sh_eth_rcv_snd_disable(ndev);
        }
 
+       /* Enable TX and RX right over here, if E-MAC change is ignored */
+       if ((mdp->cd->no_psr || mdp->no_ether_link) && phydev->link)
+               sh_eth_rcv_snd_enable(ndev);
+
+       mmiowb();
+       spin_unlock_irqrestore(&mdp->lock, flags);
+
        if (new_state && netif_msg_link(mdp))
                phy_print_status(phydev);
 }
@@ -1933,39 +1943,10 @@ static int sh_eth_get_link_ksettings(struct net_device *ndev,
 static int sh_eth_set_link_ksettings(struct net_device *ndev,
                                     const struct ethtool_link_ksettings *cmd)
 {
-       struct sh_eth_private *mdp = netdev_priv(ndev);
-       unsigned long flags;
-       int ret;
-
        if (!ndev->phydev)
                return -ENODEV;
 
-       spin_lock_irqsave(&mdp->lock, flags);
-
-       /* disable tx and rx */
-       sh_eth_rcv_snd_disable(ndev);
-
-       ret = phy_ethtool_ksettings_set(ndev->phydev, cmd);
-       if (ret)
-               goto error_exit;
-
-       if (cmd->base.duplex == DUPLEX_FULL)
-               mdp->duplex = 1;
-       else
-               mdp->duplex = 0;
-
-       if (mdp->cd->set_duplex)
-               mdp->cd->set_duplex(ndev);
-
-error_exit:
-       mdelay(1);
-
-       /* enable tx and rx */
-       sh_eth_rcv_snd_enable(ndev);
-
-       spin_unlock_irqrestore(&mdp->lock, flags);
-
-       return ret;
+       return phy_ethtool_ksettings_set(ndev->phydev, cmd);
 }
 
 /* If it is ever necessary to increase SH_ETH_REG_DUMP_MAX_REGS, the