[PATCH net-next v2 1/3] net: phy: Create sysfs reciprocal links for attached_dev/phydev

[Florian Fainelli]

There is currently no way for a program scanning /sys to know whether a
network device is attached to a particular PHY device, just like the PHY
device is not pointed back to its attached network device.

Create a symbolic link in the network device's namespace named "phydev"
which points to the PHY device and create a symbolic link in the PHY
device's namespace named "attached_dev" that points back to the network
device. These links are set up during phy_attach_direct() and removed
during phy_detach() for symetry.

Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 drivers/net/phy/phy_device.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 1219eeab69d1..8151477c7027 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -960,6 +960,15 @@ int phy_attach_direct(struct net_device *dev, struct 
phy_device *phydev,
 
        phydev->attached_dev = dev;
        dev->phydev = phydev;
+       err = sysfs_create_link(&phydev->mdio.dev.kobj, &dev->dev.kobj,
+                               "attached_dev");
+       if (err)
+               goto error;
+
+       err = sysfs_create_link(&dev->dev.kobj, &phydev->mdio.dev.kobj,
+                               "phydev");
+       if (err)
+               goto error;
 
        phydev->dev_flags = flags;
 
@@ -1050,6 +1059,8 @@ void phy_detach(struct phy_device *phydev)
        struct mii_bus *bus;
        int i;
 
+       sysfs_remove_link(&dev->dev.kobj, "phydev");
+       sysfs_remove_link(&phydev->mdio.dev.kobj, "attached_dev");
        phydev->attached_dev->phydev = NULL;
        phydev->attached_dev = NULL;
        phy_suspend(phydev);
-- 
2.9.3