Since commit d492cc2573a0 ("driver core: device.h: make struct
bus_type a const *"), the driver core can properly handle constant
struct bus_type, move the mdio_bus_type variable to be a constant
structure as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/net/phy/mdio_bus.c   | 2 +-
 drivers/net/phy/phy_device.c | 3 +--
 include/linux/phy.h          | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 08624f073014..b765466e767f 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -1426,7 +1426,7 @@ static const struct attribute_group *mdio_bus_dev_groups[] = {
 	NULL,
 };
 
-struct bus_type mdio_bus_type = {
+const struct bus_type mdio_bus_type = {
 	.name		= "mdio_bus",
 	.dev_groups	= mdio_bus_dev_groups,
 	.match		= mdio_bus_match,
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 9f37c0bfbf8d..d63dca535746 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1604,7 +1604,6 @@ EXPORT_SYMBOL(phy_attach_direct);
 struct phy_device *phy_attach(struct net_device *dev, const char *bus_id,
 			      phy_interface_t interface)
 {
-	struct bus_type *bus = &mdio_bus_type;
 	struct phy_device *phydev;
 	struct device *d;
 	int rc;
@@ -1615,7 +1614,7 @@ struct phy_device *phy_attach(struct net_device *dev, const char *bus_id,
 	/* Search the list of PHY devices on the mdio bus for the
 	 * PHY with the requested name
 	 */
-	d = bus_find_device_by_name(bus, NULL, bus_id);
+	d = bus_find_device_by_name(&mdio_bus_type, NULL, bus_id);
 	if (!d) {
 		pr_err("PHY %s not found\n", bus_id);
 		return ERR_PTR(-ENODEV);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 2249cdb5957a..c2dda21b39e1 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2129,7 +2129,7 @@ static inline bool phy_package_probe_once(struct phy_device *phydev)
 	return __phy_package_set_once(phydev, PHY_SHARED_F_PROBE_DONE);
 }
 
-extern struct bus_type mdio_bus_type;
+extern const struct bus_type mdio_bus_type;
 
 struct mdio_board_info {
 	const char	*bus_id;

---
base-commit: 400909df6e6543cb5cce3db9bbcd413d59125327
change-id: 20240213-bus_cleanup-mdio-8e1d03748437

Best regards,
-- 
Ricardo B. Marliere <ricardo@marliere.net>

On Tue, Feb 13, 2024 at 11:48:00AM -0300, Ricardo B. Marliere wrote:
> Since commit d492cc2573a0 ("driver core: device.h: make struct
> bus_type a const *"), the driver core can properly handle constant
> struct bus_type, move the mdio_bus_type variable to be a constant
> structure as well, placing it into read-only memory which can not be
> modified at runtime.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

On Tue, Feb 13, 2024 at 11:48:00AM -0300, Ricardo B. Marliere wrote:
> Since commit d492cc2573a0 ("driver core: device.h: make struct
> bus_type a const *"), the driver core can properly handle constant
> struct bus_type, move the mdio_bus_type variable to be a constant
> structure as well, placing it into read-only memory which can not be
> modified at runtime.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew