Re: [PATCH 2/2] net: phy: Fix race conditions in the driver
From: Andrew Lunn <andrew@lunn.ch>
Date: 2016-08-19 13:24:26
Also in:
linux-arm-kernel, lkml
On Fri, Aug 19, 2016 at 06:18:11PM +0530, Kedareswara rao Appana wrote:
This patch fixes the below race conditions in the driver. ---> Fix Opps after unload the driver as a module ---> Use spin locks where relevant. ---> Take reference on the external phy to prevent issues when phy driver is unloaded.
Each one of these should be an individual patch.
quoted hunk ↗ jump to hunk
Reported-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Kedareswara rao Appana <redacted> --- drivers/net/phy/xilinx_gmii2rgmii.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c index 7336fd0..cdd9d95 100644 --- a/drivers/net/phy/xilinx_gmii2rgmii.c +++ b/drivers/net/phy/xilinx_gmii2rgmii.c@@ -34,6 +34,7 @@ struct gmii2rgmii { struct phy_driver *phy_drv; struct phy_driver conv_phy_drv; int addr; + spinlock_t phy_lock;
The phy already have a lock.
quoted hunk ↗ jump to hunk
}; static int xgmiitorgmii_read_status(struct phy_device *phydev)@@ -55,7 +56,7 @@ static int xgmiitorgmii_read_status(struct phy_device *phydev) val |= BMCR_SPEED1000; else if (phydev->speed == SPEED_100) val |= BMCR_SPEED100; - else + else if (phydev->speed == SPEED_10) val |= BMCR_SPEED10;
I said you want to return an error is the PHY is using a speed your converter cannot support. I don't see an error being raised here.
quoted hunk ↗ jump to hunk
err = mdiobus_write(phydev->mdio.bus, priv->addr, XILINX_GMII2RGMII_REG,@@ -71,6 +72,8 @@ int xgmiitorgmii_probe(struct mdio_device *mdiodev) struct device *dev = &mdiodev->dev; struct device_node *np = dev->of_node, *phy_node; struct gmii2rgmii *priv; + struct mii_bus *bus; + unsigned long flags; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv)@@ -88,17 +91,43 @@ int xgmiitorgmii_probe(struct mdio_device *mdiodev) return -EPROBE_DEFER; } + spin_lock_init(&priv->phy_lock); + + bus = priv->phy_dev->mdio.bus; + if (!try_module_get(bus->owner)) { + dev_err(dev, "failed to get the bus module\n"); + return -EIO; + }
The comment at the top says you are taking a reference to the phy. Here you take a reference to the mdio bus driver???
+ + get_device(&priv->phy_dev->mdio.dev); + priv->addr = mdiodev->addr; priv->phy_drv = priv->phy_dev->drv; memcpy(&priv->conv_phy_drv, priv->phy_dev->drv, sizeof(struct phy_driver)); priv->conv_phy_drv.read_status = xgmiitorgmii_read_status; priv->phy_dev->priv = priv; + spin_lock_irqsave(&priv->phy_lock, flags); priv->phy_dev->drv = &priv->conv_phy_drv; + spin_unlock_irqrestore(&priv->phy_lock, flags);
And how is this spinlock protecting anything?
+
+ dev_set_drvdata(dev, priv);
return 0;
}
+static void xgmiitorgmii_remove(struct mdio_device *mdiodev)
+{
+ struct gmii2rgmii *priv = dev_get_drvdata(&mdiodev->dev);
+ struct mii_bus *bus;
+
+ bus = priv->phy_dev->mdio.bus;
+
+ put_device(&priv->phy_dev->mdio.dev);
+ module_put(bus->owner);
+ phy_disconnect(priv->phy_dev);Why are you disconnecting the phy?
quoted hunk ↗ jump to hunk
+} + static const struct of_device_id xgmiitorgmii_of_match[] = { { .compatible = "xlnx,gmii-to-rgmii-1.0" }, {},@@ -107,6 +136,7 @@ MODULE_DEVICE_TABLE(of, xgmiitorgmii_of_match); static struct mdio_driver xgmiitorgmii_driver = { .probe = xgmiitorgmii_probe, + .remove = xgmiitorgmii_remove, .mdiodrv.driver = { .name = "xgmiitorgmii", .of_match_table = xgmiitorgmii_of_match,-- 2.1.2