• Srinivas Kandagatla's avatar
    net:stmmac: Add check if mdiobus is registered in stmmac_mdio_unregister · a5cf5ce9
    Srinivas Kandagatla authored
    This patch adds a basic check in stmmac_mdio_unregister to see if mdio
    bus registeration for this driver was actually sucessfull or not.
    
    Use case here is, if BSP considers using mdio-gpio bus along with stmmac
    driver by passing mdio_bus_data as NULL in platform data.
    Call to stmmac_mdio_register with mdio_bus_data as NULL returns 0, which
    is a considered sucessfull call form stmmac. Then again when we unload
    the driver we just call stmmac_mdio_unregister, this is were the actual
    problem is stmmac-mdio code dont really know at this instance of calling
    that stmmac_mdio_register was actually successful.
    
    So Adding a check in stmmac_mdio_unregister is always safe.
    
    Without this patch stmmac driver calls stmmac_mdio_register from
    stmmac_release which Segfaults as mii bus was never registered at the
    first point.
    
    Originally the this bug was found when unloading an stmmac driver
    instance which uses mdio-gpio for smi access.
    Signed-off-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@st.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a5cf5ce9
stmmac_mdio.c 7.17 KB