[RFC PATCH net-next 2/7] net: phy: add mdiodev_lock(), mdiodev_lock_nested() and mdiodev_unlock()

[Aleksei Sviridkin <f@lex.la>]

Code that holds the MDIO bus across a burst of transactions has
phy_lock_mdio_bus(), which needs a phy_device. A library serving a chip
before its phy_device exists has to open-code the same mutex.

Add the mdio_device spelling beside it. The nested form is for a
library whose caller already holds the bus one level up, which is what
the EN8811H MDIO driver later in this series does.

Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@lex.la>
---
 include/linux/phy.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 3d8afe6b7f1c..e74a8f5cf5c6 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2284,6 +2284,22 @@ static inline void phy_unlock_mdio_bus(struct phy_device *phydev)
 	mutex_unlock(&phydev->mdio.bus->mdio_lock);
 }
 
+static inline void mdiodev_lock(struct mdio_device *mdiodev)
+{
+	mutex_lock(&mdiodev->bus->mdio_lock);
+}
+
+/* For a bus reached through another one, as mdiobus_read_nested() is. */
+static inline void mdiodev_lock_nested(struct mdio_device *mdiodev)
+{
+	mutex_lock_nested(&mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED);
+}
+
+static inline void mdiodev_unlock(struct mdio_device *mdiodev)
+{
+	mutex_unlock(&mdiodev->bus->mdio_lock);
+}
+
 void phy_attached_print(struct phy_device *phydev, const char *fmt, ...)
 	__printf(2, 3);
 char *phy_attached_info_irq(struct phy_device *phydev)
-- 
2.53.0