Re: [PATCH net-next v2 4/7] net: ethtool: netlink: Introduce per-phy DUMP helpers

[Kory Maincent <kory.maincent@bootlin.com>]

On Sat,  8 Mar 2025 16:54:36 +0100
Maxime Chevallier <maxime.chevallier@bootlin.com> wrote:

> As there are multiple ethnl commands that report messages based on
> phy_device information, let's introduce a set of ethnl generic dump
> helpers to allow DUMP support for each PHY on a given netdev.
> 
> This logic iterates over the phy_link_topology of each netdev (or a
> single netdev for filtered DUMP), and call ethnl_default_dump_one() with
> the req_info populated with ifindex + phyindex.
> 
> This allows re-using all the existing infra for phy-targetting commands
> that already use ethnl generic helpers.
> 
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> ---
> V2: Rebase
> 
>  net/ethtool/netlink.c | 53 +++++++++++++++++++++++++++++++++++++++++++
>  net/ethtool/netlink.h |  6 +++++
>  2 files changed, 59 insertions(+)
> 
> diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> index ae06b72239a8..a09bcd67b38f 100644
> --- a/net/ethtool/netlink.c
> +++ b/net/ethtool/netlink.c
> @@ -559,6 +559,59 @@ static int ethnl_default_dump_one(struct sk_buff *skb,
>  	return ret;
>  }
>  
> +/* Specific context for phy-targeting command DUMP operatins. We keep in
> context
> + * the latest phy_index we dumped, in case of an interrupted DUMP.
> + */
> +struct ethnl_dump_ctx_perphy {
> +	unsigned long phy_index;
> +};
> +
> +int ethnl_dump_start_perphy(struct ethnl_dump_ctx *ctx)

Could you add comments or event better, kdoc for non static function to explain
their purpose.

> +{
> +	struct ethnl_dump_ctx_perphy *dump_ctx;
> +
> +	dump_ctx = kzalloc(sizeof(*dump_ctx), GFP_KERNEL);
> +	if (!dump_ctx)
> +		return -ENOMEM;
> +
> +	ctx->cmd_ctx = dump_ctx;
> +
> +	return 0;
> +}
> +
> +void ethnl_dump_done_perphy(struct ethnl_dump_ctx *ctx)

same.

> +{
> +	kfree(ctx->cmd_ctx);
> +}
> +
> +int ethnl_dump_one_dev_perphy(struct sk_buff *skb,
> +			      struct ethnl_dump_ctx *ctx,
> +			      const struct genl_info *info)

same.

> +{
> +	struct ethnl_dump_ctx_perphy *dump_ctx = ctx->cmd_ctx;
> +	struct net_device *dev = ctx->reply_data->dev;
> +	struct phy_device_node *pdn;
> +	int ret = 0;
> +
> +	if (!dev->link_topo)
> +		return 0;
> +
> +	xa_for_each_start(&dev->link_topo->phys, dump_ctx->phy_index,
> +			  pdn, dump_ctx->phy_index) {
> +		ctx->req_info->phy_index = dump_ctx->phy_index;
> +
> +		/* We can re-use the original dump_one as ->prepare_data in
> +		 * commands use ethnl_req_get_phydev(), which gets the PHY
> from
> +		 * what's in req_info
> +		 */
> +		ret = ethnl_default_dump_one(skb, ctx, info);
> +		if (ret)
> +			break;
> +	}
> +
> +	return ret;
> +}

Regards,
---
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com