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    Subject[PATCH 3.16 239/366] sh_eth: fix invalid context bug while changing link options by ethtool
    3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>

    commit 5cb3f52a11e18628fc4bee76dd14b1f0b76349de upstream.

    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>
    [bwh: Backported to 3.16:
    - Keep using phy_ethtool_sset()
    - Adjust context]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    --- a/drivers/net/ethernet/renesas/sh_eth.c
    +++ b/drivers/net/ethernet/renesas/sh_eth.c
    @@ -1727,8 +1727,15 @@ static void sh_eth_adjust_link(struct ne
    {
    struct sh_eth_private *mdp = netdev_priv(ndev);
    struct phy_device *phydev = mdp->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;
    @@ -1749,18 +1756,21 @@ static void sh_eth_adjust_link(struct ne
    ECMR);
    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);
    }
    @@ -1843,35 +1853,8 @@ static int sh_eth_set_settings(struct ne
    struct ethtool_cmd *ecmd)
    {
    struct sh_eth_private *mdp = netdev_priv(ndev);
    - unsigned long flags;
    - int ret;
    -
    - spin_lock_irqsave(&mdp->lock, flags);

    - /* disable tx and rx */
    - sh_eth_rcv_snd_disable(ndev);
    -
    - ret = phy_ethtool_sset(mdp->phydev, ecmd);
    - if (ret)
    - goto error_exit;
    -
    - if (ecmd->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_sset(mdp->phydev, ecmd);
    }

    static int sh_eth_nway_reset(struct net_device *ndev)
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