Prevent unloading mii bus driver module when other modules have references to some
phydevs on that bus. Added a new member (module owner) to struct mii_bus and added
code to increment the mii bus owner module usage count on phy_connect and decrement
it on phy_disconnect

Set the module owner in the ucc_geth_mdio driver.

Signed-off-by: Ionut Nicu <redacted>
---
 drivers/net/phy/phy_device.c |    9 ++++++++-
 drivers/net/ucc_geth_mii.c   |    3 +++
 include/linux/phy.h          |    4 ++++
 3 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 5b9e175..7dc5480 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c

@@ -178,6 +178,10 @@ struct phy_device * phy_connect(struct net_device *dev, const char *phy_id,
 	if (phydev->irq > 0)
 		phy_start_interrupts(phydev);
 
+	/* Increment the usage count of the mii bus owner */
+	if (!try_module_get(phydev->bus->owner))
+		return ERR_PTR(-EFAULT);

+
 	return phydev;
 }
 EXPORT_SYMBOL(phy_connect);

@@ -192,9 +196,12 @@ void phy_disconnect(struct phy_device *phydev)
 		phy_stop_interrupts(phydev);
 
 	phy_stop_machine(phydev);
-	
+
 	phydev->adjust_link = NULL;
 
+	/* Decrement the reference count for the mii bus owner */
+	module_put(phydev->bus->owner);
+
 	phy_detach(phydev);
 }
 EXPORT_SYMBOL(phy_disconnect);

diff --git a/drivers/net/ucc_geth_mii.c b/drivers/net/ucc_geth_mii.c
index a3af4ea..84c7295 100644
--- a/drivers/net/ucc_geth_mii.c
+++ b/drivers/net/ucc_geth_mii.c

@@ -217,6 +217,9 @@ static int uec_mdio_probe(struct of_device *ofdev, const struct of_device_id *ma
 		}
 	}
 
+	/* register ourselves as the owner of this bus */
+	new_bus->owner = THIS_MODULE;
+
 	err = mdiobus_register(new_bus);
 	if (0 != err) {
 		printk(KERN_ERR "%s: Cannot register as MDIO bus\n",

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 554836e..04ff6a5 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h

@@ -82,6 +82,10 @@ struct mii_bus {
 	const char *name;
 	int id;
 	void *priv;
+
+	/* The module that owns this bus */
+	struct module *owner;
+
 	int (*read)(struct mii_bus *bus, int phy_id, int regnum);
 	int (*write)(struct mii_bus *bus, int phy_id, int regnum, u16 val);
 	int (*reset)(struct mii_bus *bus);