Merge branch 'ksettings-locking-fixes'

Andrew Lunn says:

====================
ksettings_{get|set} lock fixes

Walter Stoll <Walter.Stoll@duagon.com> reported a race condition
between "ethtool -s eth0 speed 100 duplex full autoneg off" and phylib
reading the current status from the PHY. Both ksetting_get and
ksetting_set fail the take the phydev mutex, and as a result, there is
a small window of time where the phydev members are not self
consistent.

Patch 1 fixes phy_ethtool_ksettings_get by adding the needed lock.
Patches 2 and 3 move code around and perform to refactoring, to allow
patch 4 to fix phy_ethtool_ksettings_set by added the lock.

Thanks go to Walter for the detailed origional report, suggested fix,
and testing of the proposed patches.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 81 insertions, 59 deletions

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index f124a8a58bd41a..a3bfb156c83d7b 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -243,62 +243,10 @@ static void phy_sanitize_settings(struct phy_device *phydev)
 	}
 }
 
-int phy_ethtool_ksettings_set(struct phy_device *phydev,
-			      const struct ethtool_link_ksettings *cmd)
-{
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising);
-	u8 autoneg = cmd->base.autoneg;
-	u8 duplex = cmd->base.duplex;
-	u32 speed = cmd->base.speed;
-
-	if (cmd->base.phy_address != phydev->mdio.addr)
-		return -EINVAL;
-
-	linkmode_copy(advertising, cmd->link_modes.advertising);
-
-	/* We make sure that we don't pass unsupported values in to the PHY */
-	linkmode_and(advertising, advertising, phydev->supported);
-
-	/* Verify the settings we care about. */
-	if (autoneg != AUTONEG_ENABLE && autoneg != AUTONEG_DISABLE)
-		return -EINVAL;
-
-	if (autoneg == AUTONEG_ENABLE && linkmode_empty(advertising))
-		return -EINVAL;
-
-	if (autoneg == AUTONEG_DISABLE &&
-	    ((speed != SPEED_1000 &&
-	      speed != SPEED_100 &&
-	      speed != SPEED_10) ||
-	     (duplex != DUPLEX_HALF &&
-	      duplex != DUPLEX_FULL)))
-		return -EINVAL;
-
-	phydev->autoneg = autoneg;
-
-	if (autoneg == AUTONEG_DISABLE) {
-		phydev->speed = speed;
-		phydev->duplex = duplex;
-	}
-
-	linkmode_copy(phydev->advertising, advertising);
-
-	linkmode_mod_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
-			 phydev->advertising, autoneg == AUTONEG_ENABLE);
-
-	phydev->master_slave_set = cmd->base.master_slave_cfg;
-	phydev->mdix_ctrl = cmd->base.eth_tp_mdix_ctrl;
-
-	/* Restart the PHY */
-	phy_start_aneg(phydev);
-
-	return 0;
-}
-EXPORT_SYMBOL(phy_ethtool_ksettings_set);
-
 void phy_ethtool_ksettings_get(struct phy_device *phydev,
 			       struct ethtool_link_ksettings *cmd)
 {
+	mutex_lock(&phydev->lock);
 	linkmode_copy(cmd->link_modes.supported, phydev->supported);
 	linkmode_copy(cmd->link_modes.advertising, phydev->advertising);
 	linkmode_copy(cmd->link_modes.lp_advertising, phydev->lp_advertising);
@@ -317,6 +265,7 @@ void phy_ethtool_ksettings_get(struct phy_device *phydev,
 	cmd->base.autoneg = phydev->autoneg;
 	cmd->base.eth_tp_mdix_ctrl = phydev->mdix_ctrl;
 	cmd->base.eth_tp_mdix = phydev->mdix;
+	mutex_unlock(&phydev->lock);
 }
 EXPORT_SYMBOL(phy_ethtool_ksettings_get);
 
@@ -751,7 +700,7 @@ static int phy_check_link_status(struct phy_device *phydev)
 }
 
 /**
- * phy_start_aneg - start auto-negotiation for this PHY device
+ * _phy_start_aneg - start auto-negotiation for this PHY device
  * @phydev: the phy_device struct
  *
  * Description: Sanitizes the settings (if we're not autonegotiating
@@ -759,25 +708,43 @@ static int phy_check_link_status(struct phy_device *phydev)
  *   If the PHYCONTROL Layer is operating, we change the state to
  *   reflect the beginning of Auto-negotiation or forcing.
  */
-int phy_start_aneg(struct phy_device *phydev)
+static int _phy_start_aneg(struct phy_device *phydev)
 {
 	int err;
 
+	lockdep_assert_held(&phydev->lock);
+
 	if (!phydev->drv)
 		return -EIO;
 
-	mutex_lock(&phydev->lock);
-
 	if (AUTONEG_DISABLE == phydev->autoneg)
 		phy_sanitize_settings(phydev);
 
 	err = phy_config_aneg(phydev);
 	if (err < 0)
-		goto out_unlock;
+		return err;
 
 	if (phy_is_started(phydev))
 		err = phy_check_link_status(phydev);
-out_unlock:
+
+	return err;
+}
+
+/**
+ * phy_start_aneg - start auto-negotiation for this PHY device
+ * @phydev: the phy_device struct
+ *
+ * Description: Sanitizes the settings (if we're not autonegotiating
+ *   them), and then calls the driver's config_aneg function.
+ *   If the PHYCONTROL Layer is operating, we change the state to
+ *   reflect the beginning of Auto-negotiation or forcing.
+ */
+int phy_start_aneg(struct phy_device *phydev)
+{
+	int err;
+
+	mutex_lock(&phydev->lock);
+	err = _phy_start_aneg(phydev);
 	mutex_unlock(&phydev->lock);
 
 	return err;
@@ -800,6 +767,61 @@ static int phy_poll_aneg_done(struct phy_device *phydev)
 	return ret < 0 ? ret : 0;
 }
 
+int phy_ethtool_ksettings_set(struct phy_device *phydev,
+			      const struct ethtool_link_ksettings *cmd)
+{
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising);
+	u8 autoneg = cmd->base.autoneg;
+	u8 duplex = cmd->base.duplex;
+	u32 speed = cmd->base.speed;
+
+	if (cmd->base.phy_address != phydev->mdio.addr)
+		return -EINVAL;
+
+	linkmode_copy(advertising, cmd->link_modes.advertising);
+
+	/* We make sure that we don't pass unsupported values in to the PHY */
+	linkmode_and(advertising, advertising, phydev->supported);
+
+	/* Verify the settings we care about. */
+	if (autoneg != AUTONEG_ENABLE && autoneg != AUTONEG_DISABLE)
+		return -EINVAL;
+
+	if (autoneg == AUTONEG_ENABLE && linkmode_empty(advertising))
+		return -EINVAL;
+
+	if (autoneg == AUTONEG_DISABLE &&
+	    ((speed != SPEED_1000 &&
+	      speed != SPEED_100 &&
+	      speed != SPEED_10) ||
+	     (duplex != DUPLEX_HALF &&
+	      duplex != DUPLEX_FULL)))
+		return -EINVAL;
+
+	mutex_lock(&phydev->lock);
+	phydev->autoneg = autoneg;
+
+	if (autoneg == AUTONEG_DISABLE) {
+		phydev->speed = speed;
+		phydev->duplex = duplex;
+	}
+
+	linkmode_copy(phydev->advertising, advertising);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
+			 phydev->advertising, autoneg == AUTONEG_ENABLE);
+
+	phydev->master_slave_set = cmd->base.master_slave_cfg;
+	phydev->mdix_ctrl = cmd->base.eth_tp_mdix_ctrl;
+
+	/* Restart the PHY */
+	_phy_start_aneg(phydev);
+
+	mutex_unlock(&phydev->lock);
+	return 0;
+}
+EXPORT_SYMBOL(phy_ethtool_ksettings_set);
+
 /**
  * phy_speed_down - set speed to lowest speed supported by both link partners
  * @phydev: the phy_device struct