Re: [PATCH net-next v18 07/10] net: phy: phy_link_topology: Add a helper to retrieve ports

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Le 27/09/2026 à 15:36, Maxime Chevallier a écrit :
> In order to allow netlink access to phy_ports, let's add a helper to
> retrieve them. When handling a port coming from phy_link_topology, the
> caller must hold rtnl until it's done with it.
> 
> We don't really support PHY and phy_port operation on ops-locked devices
> yet, warn when we try to do so on such an interface.
> 
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Tested-by: Aleksei Sviridkin <f@lex.la>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>

> ---
>   drivers/net/phy/phy_link_topology.c |  8 ++++++++
>   include/linux/phy_link_topology.h   | 25 +++++++++++++++++++++++++
>   2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_link_topology.c b/drivers/net/phy/phy_link_topology.c
> index 28c5bf3a8849..214ccce23cf6 100644
> --- a/drivers/net/phy/phy_link_topology.c
> +++ b/drivers/net/phy/phy_link_topology.c
> @@ -65,6 +65,14 @@ int phy_link_topo_add_port(struct net_device *dev, struct phy_port *port)
>   	struct phy_link_topology *topo;
>   	int ret;
>   
> +	/* Ports can now be queried without rtnl for ops-locked devices, which
> +	 * we don't support now as port retrieval is done under rtnl.
> +	 * We don't have phy_port enabled devices yet, let's make sure
> +	 * we are loudly warned about that when it happens.
> +	 */
> +	if (WARN_ON_ONCE(dev->netdev_ops && netdev_need_ops_lock(dev)))
> +		return -EOPNOTSUPP;
> +
>   	topo = phy_link_topo_get_or_alloc(dev);
>   	if (IS_ERR(topo))
>   		return PTR_ERR(topo);
> diff --git a/include/linux/phy_link_topology.h b/include/linux/phy_link_topology.h
> index 296ee514ba46..f2e493c433ff 100644
> --- a/include/linux/phy_link_topology.h
> +++ b/include/linux/phy_link_topology.h
> @@ -13,6 +13,7 @@
>   
>   #include <linux/ethtool.h>
>   #include <linux/netdevice.h>
> +#include <linux/rtnetlink.h>
>   
>   struct xarray;
>   struct phy_device;
> @@ -71,6 +72,24 @@ phy_link_topo_get_phy(struct net_device *dev, u32 phyindex)
>   	return NULL;
>   }
>   
> +static inline struct phy_port *
> +phy_link_topo_get_port(struct net_device *dev, u32 port_id)
> +{
> +	struct phy_link_topology *topo = dev->link_topo;
> +
> +	if (!topo)
> +		return NULL;
> +
> +	/* ports in the topo are RTNL protected, but may be accessed under
> +	 * netdev_lock for ops-locked devices. For now keep them under rtnl
> +	 * protection, as no ops-locked devices have phy_port capabilities
> +	 * yet.
> +	 */
> +	ASSERT_RTNL();
> +
> +	return xa_load(&topo->ports, port_id);
> +}
> +
>   #else
>   static inline int phy_link_topo_add_phy(struct net_device *dev,
>   					struct phy_device *phy,
> @@ -100,6 +119,12 @@ phy_link_topo_get_phy(struct net_device *dev, u32 phyindex)
>   {
>   	return NULL;
>   }
> +
> +static inline struct phy_port *
> +phy_link_topo_get_port(struct net_device *dev, u32 port_id)
> +{
> +	return NULL;
> +}
>   #endif
>   
>   #endif /* __PHY_LINK_TOPOLOGY_H */