Re: [PATCH net-next 1/5] net/ethtool: add netlink interface for the PLCA RS

From: Leon Romanovsky
Date: Thu Jan 05 2023 - 03:55:33 EST


On Wed, Jan 04, 2023 at 03:05:44PM +0100, Piergiorgio Beruto wrote:
> Add support for configuring the PLCA Reconciliation Sublayer on
> multi-drop PHYs that support IEEE802.3cg-2019 Clause 148 (e.g.,
> 10BASE-T1S). This patch adds the appropriate netlink interface
> to ethtool.
>
> Signed-off-by: Piergiorgio Beruto <piergiorgio.beruto@xxxxxxxxx>
> ---
> Documentation/networking/ethtool-netlink.rst | 138 ++++++++++
> MAINTAINERS | 6 +
> include/linux/ethtool.h | 12 +
> include/linux/phy.h | 57 ++++
> include/uapi/linux/ethtool_netlink.h | 25 ++
> net/ethtool/Makefile | 2 +-
> net/ethtool/netlink.c | 29 ++
> net/ethtool/netlink.h | 6 +
> net/ethtool/plca.c | 276 +++++++++++++++++++
> 9 files changed, 550 insertions(+), 1 deletion(-)
> create mode 100644 net/ethtool/plca.c

<...>

> --- /dev/null
> +++ b/net/ethtool/plca.c
> @@ -0,0 +1,276 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/phy.h>
> +#include <linux/ethtool_netlink.h>
> +
> +#include "netlink.h"
> +#include "common.h"
> +
> +struct plca_req_info {
> + struct ethnl_req_info base;
> +};
> +
> +struct plca_reply_data {
> + struct ethnl_reply_data base;
> + struct phy_plca_cfg plca_cfg;
> + struct phy_plca_status plca_st;
> +};
> +
> +// Helpers ------------------------------------------------------------------ //
> +
> +#define PLCA_REPDATA(__reply_base) \
> + container_of(__reply_base, struct plca_reply_data, base)
> +
> +static inline void plca_update_sint(int *dst, const struct nlattr *attr,
> + bool *mod)

No inline function in *.c files.

> +{
> + if (attr) {
> + *dst = nla_get_u32(attr);
> + *mod = true;
> + }

Success oriented approach, please
if (!attr)
return;

> +}
> +
> +// PLCA get configuration message ------------------------------------------- //
> +
> +const struct nla_policy ethnl_plca_get_cfg_policy[] = {
> + [ETHTOOL_A_PLCA_HEADER] =
> + NLA_POLICY_NESTED(ethnl_header_policy),
> +};
> +
> +static int plca_get_cfg_prepare_data(const struct ethnl_req_info *req_base,
> + struct ethnl_reply_data *reply_base,
> + struct genl_info *info)
> +{
> + struct plca_reply_data *data = PLCA_REPDATA(reply_base);
> + struct net_device *dev = reply_base->dev;
> + const struct ethtool_phy_ops *ops;
> + int ret;
> +
> + // check that the PHY device is available and connected
> + if (!dev->phydev) {
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
> +
> + // note: rtnl_lock is held already by ethnl_default_doit
> + ops = ethtool_phy_ops;
> + if (!ops || !ops->get_plca_cfg) {
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
> +
> + ret = ethnl_ops_begin(dev);
> + if (ret < 0)
> + goto out;

I see that many places in the code used this ret > 0 check, but it looks
like the right check is if (ret).

Thanks