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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-09-24 20:36:02 +0100
committerDavid S. Miller <davem@davemloft.net>2015-09-24 23:04:52 -0700
commit3e3aaf649416988ca8be4ad2c52dc24d8be7b46e (patch)
tree94f37082bd659379c74f9627c7be48c5147ec2fe /drivers/net/phy
parente496ae690b2faff751e1849fb97b060615e21f28 (diff)
downloadlinux-linaro-stable-3e3aaf649416988ca8be4ad2c52dc24d8be7b46e.tar.gz
phy: fix mdiobus module safety
Re-implement the mdiobus module refcounting to ensure that we actually ensure that the mdiobus module code does not go away while we might call into it. The old scheme using bus->dev.driver was buggy, because bus->dev is a class device which never has a struct device_driver associated with it, and hence the associated code trying to obtain a refcount did nothing useful. Instead, take the approach that other subsystems do: pass the module when calling mdiobus_register(), and record that in the mii_bus struct. When we need to increment the module use count in the phy code, use this stored pointer. When the phy is deteched, drop the module refcount, remembering that the phy device might go away at that point. This doesn't stop the mii_bus going away while there are in-use phys - it merely stops the underlying code vanishing. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/phy')
-rw-r--r--drivers/net/phy/mdio_bus.c5
-rw-r--r--drivers/net/phy/phy_device.c32
2 files changed, 21 insertions, 16 deletions
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 67553e13bd36..992406624b7c 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -244,7 +244,7 @@ static inline void of_mdiobus_link_phydev(struct mii_bus *mdio,
*
* Returns 0 on success or < 0 on error.
*/
-int mdiobus_register(struct mii_bus *bus)
+int __mdiobus_register(struct mii_bus *bus, struct module *owner)
{
int i, err;
@@ -255,6 +255,7 @@ int mdiobus_register(struct mii_bus *bus)
BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
bus->state != MDIOBUS_UNREGISTERED);
+ bus->owner = owner;
bus->dev.parent = bus->parent;
bus->dev.class = &mdio_bus_class;
bus->dev.groups = NULL;
@@ -296,7 +297,7 @@ error:
device_del(&bus->dev);
return err;
}
-EXPORT_SYMBOL(mdiobus_register);
+EXPORT_SYMBOL(__mdiobus_register);
void mdiobus_unregister(struct mii_bus *bus)
{
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c0f211127274..03adf328f49b 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -582,10 +582,15 @@ EXPORT_SYMBOL(phy_init_hw);
int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
u32 flags, phy_interface_t interface)
{
+ struct mii_bus *bus = phydev->bus;
struct device *d = &phydev->dev;
- struct module *bus_module;
int err;
+ if (!try_module_get(bus->owner)) {
+ dev_err(&dev->dev, "failed to get the bus module\n");
+ return -EIO;
+ }
+
/* Assume that if there is no driver, that it doesn't
* exist, and we should use the genphy driver.
*/
@@ -600,20 +605,13 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
err = device_bind_driver(d);
if (err)
- return err;
+ goto error;
}
if (phydev->attached_dev) {
dev_err(&dev->dev, "PHY already attached\n");
- 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;
+ err = -EBUSY;
+ goto error;
}
phydev->attached_dev = dev;
@@ -636,6 +634,10 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
phy_resume(phydev);
return err;
+
+error:
+ module_put(bus->owner);
+ return err;
}
EXPORT_SYMBOL(phy_attach_direct);
@@ -680,11 +682,9 @@ EXPORT_SYMBOL(phy_attach);
*/
void phy_detach(struct phy_device *phydev)
{
+ struct mii_bus *bus;
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);
@@ -700,6 +700,10 @@ void phy_detach(struct phy_device *phydev)
break;
}
}
+
+ bus = phydev->bus;
+
+ module_put(bus->owner);
}
EXPORT_SYMBOL(phy_detach);