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Date:   Tue, 21 Nov 2023 02:40:27 +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 06/10] net: ethtool: Introduce a command
 to list PHYs on an interface
Message-ID: <97c04999-c3fe-421e-a8eb-642aff647536@lunn.ch>
References: <20231117162323.626979-1-maxime.chevallier@bootlin.com>
 <20231117162323.626979-7-maxime.chevallier@bootlin.com>
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In-Reply-To: <20231117162323.626979-7-maxime.chevallier@bootlin.com>
Precedence: bulk

> +ethnl_phy_reply_size(const struct ethnl_req_info *req_base,
> +		     struct netlink_ext_ack *extack)
> +{
> +	struct phy_device_node *pdn;
> +	struct phy_device *phydev;
> +	struct link_topology *lt;
> +	unsigned long index;
> +	size_t size;
> +
> +	lt = &req_base->dev->link_topo;
> +
> +	size = nla_total_size(0);
> +
> +	xa_for_each(&lt->phys, index, pdn) {
> +		phydev = pdn->phy;
> +
> +		/* ETHTOOL_A_PHY_INDEX */
> +		size += nla_total_size(sizeof(u32));
> +
> +		/* ETHTOOL_A_DRVNAME */
> +		size += nla_total_size(strlen(phydev->drv->name));
> +
> +		/* ETHTOOL_A_NAME */
> +		size += nla_total_size(strlen(dev_name(&phydev->mdio.dev)));
> +
> +		/* ETHTOOL_A_PHY_UPSTREAM_TYPE */
> +		size += nla_total_size(sizeof(u8));
> +
> +		/* ETHTOOL_A_PHY_ID */
> +		size += nla_total_size(sizeof(u32));
> +
> +		if (phy_on_sfp(phydev)) {
> +			/* ETHTOOL_A_PHY_UPSTREAM_SFP_NAME */
> +			if (sfp_get_name(pdn->parent_sfp_bus))
> +				size += nla_total_size(strlen(sfp_get_name(pdn->parent_sfp_bus)));

Have you tried a modular build?

sfp_get_name() could be in a module, and then you will get linker
errors. It is all a bit messy calling into phylib from ethtool :-(

This might actually be the only function you need? If so, its small
enough you can move it into a header as a static inline function.

       Andrew