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net: phy: Ensure the MDIO bus module is held 

This commit adds proper module_{get,put} to prevent the MDIO bus module
from being unloaded while the phydev is connected. By doing so, we fix
a kernel panic produced when a MDIO driver is removed, but the phydev
that relies on it is attached and running.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ezequiel Garcia 2014-07-23 16:47:32 -03:00 committed by David S. Miller
parent a71e3c3796
commit b3565f278a
1 changed files with 13 additions and 0 deletions
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13
drivers/net/phy/phy_device.c
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@ -575,6 +575,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
u32 flags, phy_interface_t interface)
{
struct device *d = &phydev->dev;
struct module *bus_module;
int err;
/* Assume that if there is no driver, that it doesn't
@ -599,6 +600,14 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
return -EBUSY;
}
/* Increment the bus module reference count */
bus_module = phydev->bus->dev.driver ?
phydev->bus->dev.driver->owner : NULL;
if (!try_module_get(bus_module)) {
dev_err(&dev->dev, "failed to get the bus module\n");
return -EIO;
}
phydev->attached_dev = dev;
dev->phydev = phydev;
@ -664,6 +673,10 @@ EXPORT_SYMBOL(phy_attach);
void phy_detach(struct phy_device *phydev)
{
int i;
if (phydev->bus->dev.driver)
module_put(phydev->bus->dev.driver->owner);
phydev->attached_dev->phydev = NULL;
phydev->attached_dev = NULL;
phy_suspend(phydev);