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Date:   Tue, 21 Nov 2023 01:24:47 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Russell King <linux@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Herve Codina <herve.codina@bootlin.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        =?iso-8859-1?Q?K=F6ry?= Maincent <kory.maincent@bootlin.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>
Subject: Re: [RFC PATCH net-next v2 01/10] net: phy: Introduce ethernet link
 topology representation
Message-ID: <9079c9f5-5531-4c38-b9c9-975ed3d96104@lunn.ch>
References: <20231117162323.626979-1-maxime.chevallier@bootlin.com>
 <20231117162323.626979-2-maxime.chevallier@bootlin.com>
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In-Reply-To: <20231117162323.626979-2-maxime.chevallier@bootlin.com>
Precedence: bulk

> +int link_topo_add_phy(struct link_topology *lt, struct phy_device *phy,
> +		      enum phy_upstream upt, void *upstream)
> +{
> +	ret = xa_alloc_cyclic(&lt->phys, &phy->phyindex, pdn, xa_limit_32b,
> +			      &lt->next_phy_index, GFP_KERNEL);
> +	if (ret)
> +		goto err;
> +
> +	return 0;

It looks like that could be just return xa_alloc_cyclic(...);

> diff --git a/include/linux/link_topology.h b/include/linux/link_topology.h

I think this filename is too generic. Maybe phy_link_topology.h, or
move it into include/net.

> +struct phy_device *link_topo_get_phy(struct link_topology *lt, int phyindex);
> +int link_topo_add_phy(struct link_topology *lt, struct phy_device *phy,
> +		      enum phy_upstream upt, void *upstream);
> +
> +void link_topo_del_phy(struct link_topology *lt, struct phy_device *phy);

What is the locking for these functions? Are you assuming RTNL? Maybe
add ASSERT_RTNL(); into them to make this clear.

> diff --git a/include/linux/link_topology_core.h b/include/linux/link_topology_core.h

Again, i think this filename is too generic.

> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index a16c9cc063fe..7021a0d3d982 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -40,7 +40,6 @@
>  #include <net/dcbnl.h>
>  #endif
>  #include <net/netprio_cgroup.h>
> -
>  #include <linux/netdev_features.h>

Whitespace change.

>  #include <linux/neighbour.h>
>  #include <uapi/linux/netdevice.h>
> @@ -52,6 +51,7 @@
>  #include <net/net_trackers.h>
>  #include <net/net_debug.h>
>  #include <net/dropreason-core.h>
> +#include <linux/link_topology_core.h>
>  
>  struct netpoll_info;
>  struct device;
> @@ -2405,6 +2405,7 @@ struct net_device {
>  #if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
>  	struct netprio_map __rcu *priomap;
>  #endif
> +	struct link_topology	link_topo;
>  	struct phy_device	*phydev;
>  	struct sfp_bus		*sfp_bus;
>  	struct lock_class_key	*qdisc_tx_busylock;
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 3cc52826f18e..d698180b1df0 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -543,6 +543,8 @@ struct macsec_ops;
>   * @drv: Pointer to the driver for this PHY instance
>   * @devlink: Create a link between phy dev and mac dev, if the external phy
>   *           used by current mac interface is managed by another mac interface.
> + * @phyindex: Unique id across the phy's parent tree of phys to address the PHY
> + *	      from userspace, similar to ifindex. It's never recycled.
>   * @phy_id: UID for this device found during discovery
>   * @c45_ids: 802.3-c45 Device Identifiers if is_c45.
>   * @is_c45:  Set to true if this PHY uses clause 45 addressing.
> @@ -640,6 +642,7 @@ struct phy_device {
>  
>  	struct device_link *devlink;
>  
> +	int phyindex;

Is this int, or unsigned int? Is a negative value possible and legal?

> +enum phy_upstream {
> +	PHY_UPSTREAM_MAC,
> +	PHY_UPSTREAM_SFP,
> +	PHY_UPSTREAM_PHY,
> +};

Please document what these actually mean.

       Andrew