Re: [PATCH net-next v6 4/7] net: stmmac: introduce pcs_init/pcs_exit stmmac operations

Simon Horman
2024-05-11T18:11:29Z

On Fri, May 10, 2024 at 09:38:11AM +0200, Romain Gantois wrote:
> From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
>
> Introduce a mechanism whereby platforms can create their PCS instances
> prior to the network device being published to userspace, but after
> some of the core stmmac initialisation has been completed. This means
> that the data structures that platforms need will be available.
>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
> Co-developed-by: Romain Gantois <romain.gantois@bootlin.com>
> Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 8 +++++++-
> include/linux/stmmac.h | 2 ++
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index 778d79cdb2e6d..f562c563aab55 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -505,7 +505,10 @@ int stmmac_pcs_setup(struct net_device *ndev)
> priv = netdev_priv(ndev);
> mode = priv->plat->phy_interface;
>
> - if (priv->plat->mdio_bus_data && priv->plat->mdio_bus_data->has_xpcs) {
> + if (priv->plat->pcs_init) {
> + ret = priv->plat->pcs_init(priv);
> + } else if (priv->plat->mdio_bus_data &&
> + priv->plat->mdio_bus_data->has_xpcs) {
> /* Try to probe the XPCS by scanning all addresses */
> for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
> xpcs = xpcs_create_mdiodev(priv->mii, addr, mode);

I am unsure if this can occur, but if priv->plat->pcs_init returns 0 then
xpcs will be used while uninitialised towards the end of this function.

Flagged by Smatch.

...