[PATCH net-next v7 1/3] net: ethtool: Introduce per-PHY DUMP operations

Maxime Chevallier
2025-04-22T18:27:56Z

ethnl commands that target a phy_device need a DUMP implementation that
will fill the reply for every PHY behind a netdev. We therefore need to
iterate over the dev->topo to list them.

When multiple PHYs are behind the same netdev, it's also useful to
perform DUMP with a filter on a given netdev, to get the capability of
every PHY.

Implement dedicated genl ->start(), ->dumpit() and ->done() operations
for PHY-targetting command, allowing filtered dumps and using a dump
context that keep track of the PHY iteration for multi-message dump.

PSE-PD and PLCA are converted to this new set of ops along the way.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
V7: Move to netdev_hold()

net/ethtool/netlink.c | 181 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 172 insertions(+), 9 deletions(-)

diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 977beeaaa2f9..42b8aa5569a7 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -357,6 +357,16 @@ struct ethnl_dump_ctx {
unsigned long pos_ifindex;
};

+/**
+ * struct ethnl_perphy_dump_ctx - context for dumpit() PHY-aware callbacks
+ * @ethnl_ctx: generic ethnl context
+ * @pos_phyindex: iterator position for multi-msg DUMP
+ */
+struct ethnl_perphy_dump_ctx {
+ struct ethnl_dump_ctx ethnl_ctx;
+ unsigned long pos_phyindex;
+};
+
static const struct ethnl_request_ops *
ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
[ETHTOOL_MSG_STRSET_GET] = &ethnl_strset_request_ops,
@@ -407,6 +417,12 @@ static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb)
return (struct ethnl_dump_ctx *)cb->ctx;
}

+static struct ethnl_perphy_dump_ctx *
+ethnl_perphy_dump_context(struct netlink_callback *cb)
+{
+ return (struct ethnl_perphy_dump_ctx *)cb->ctx;
+}
+
/**
* ethnl_default_parse() - Parse request message
* @req_info: pointer to structure to put data into
@@ -662,6 +678,153 @@ static int ethnl_default_start(struct netlink_callback *cb)
return ret;
}

+/* perphy ->start() handler for GET requests */
+static int ethnl_perphy_start(struct netlink_callback *cb)
+{
+ struct ethnl_perphy_dump_ctx *phy_ctx = ethnl_perphy_dump_context(cb);
+ const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+ struct ethnl_dump_ctx *ctx = &phy_ctx->ethnl_ctx;
+ struct ethnl_reply_data *reply_data;
+ const struct ethnl_request_ops *ops;
+ struct ethnl_req_info *req_info;
+ struct genlmsghdr *ghdr;
+ int ret;
+
+ BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
+
+ ghdr = nlmsg_data(cb->nlh);
+ ops = ethnl_default_requests[ghdr->cmd];
+ if (WARN_ONCE(!ops, "cmd %u has no ethnl_request_ops\n", ghdr->cmd))
+ return -EOPNOTSUPP;
+ req_info = kzalloc(ops->req_info_size, GFP_KERNEL);
+ if (!req_info)
+ return -ENOMEM;
+ reply_data = kmalloc(ops->reply_data_size, GFP_KERNEL);
+ if (!reply_data) {
+ ret = -ENOMEM;
+ goto free_req_info;
+ }
+
+ /* Don't ignore the dev even for DUMP requests */
+ ret = ethnl_default_parse(req_info, &info->info, ops, false);
+ if (ret < 0)
+ goto free_reply_data;
+
+ ctx->ops = ops;
+ ctx->req_info = req_info;
+ ctx->reply_data = reply_data;
+ ctx->pos_ifindex = 0;
+
+ return 0;
+
+free_reply_data:
+ kfree(reply_data);
+free_req_info:
+ kfree(req_info);
+
+ return ret;
+}
+
+static int ethnl_perphy_dump_one_dev(struct sk_buff *skb,
+ struct net_device *dev,
+ struct ethnl_perphy_dump_ctx *ctx,
+ const struct genl_info *info)
+{
+ struct ethnl_dump_ctx *ethnl_ctx = &ctx->ethnl_ctx;
+ struct phy_device_node *pdn;
+ int ret = 0;
+
+ if (!dev->link_topo)
+ return 0;
+
+ xa_for_each_start(&dev->link_topo->phys, ctx->pos_phyindex, pdn,
+ ctx->pos_phyindex) {
+ ethnl_ctx->req_info->phy_index = ctx->pos_phyindex;
+
+ /* We can re-use the original dump_one as ->prepare_data in
+ * commands use ethnl_req_get_phydev(), which gets the PHY from
+ * the req_info->phy_index
+ */
+ ret = ethnl_default_dump_one(skb, dev, ethnl_ctx, info);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int ethnl_perphy_dump_all_dev(struct sk_buff *skb,
+ struct ethnl_perphy_dump_ctx *ctx,
+ const struct genl_info *info)
+{
+ struct ethnl_dump_ctx *ethnl_ctx = &ctx->ethnl_ctx;
+ struct net *net = sock_net(skb->sk);
+ netdevice_tracker dev_tracker;
+ struct net_device *dev;
+ int ret = 0;
+
+ rcu_read_lock();
+ for_each_netdev_dump(net, dev, ethnl_ctx->pos_ifindex) {
+ netdev_hold(dev, &dev_tracker, GFP_ATOMIC);
+ rcu_read_unlock();
+
+ /* per-PHY commands use ethnl_req_get_phydev(), which needs the
+ * net_device in the req_info
+ */
+ ethnl_ctx->req_info->dev = dev;
+ ret = ethnl_perphy_dump_one_dev(skb, dev, ctx, info);
+
+ rcu_read_lock();
+ netdev_put(dev, &dev_tracker);
+
+ if (ret < 0 && ret != -EOPNOTSUPP) {
+ if (likely(skb->len))
+ ret = skb->len;
+ break;
+ }
+ ret = 0;
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/* perphy ->dumpit() handler for GET requests. */
+static int ethnl_perphy_dumpit(struct sk_buff *skb,
+ struct netlink_callback *cb)
+{
+ struct ethnl_perphy_dump_ctx *ctx = ethnl_perphy_dump_context(cb);
+ struct ethnl_dump_ctx *ethnl_ctx = &ctx->ethnl_ctx;
+ int ret = 0;
+
+ if (ethnl_ctx->req_info->dev) {
+ ret = ethnl_perphy_dump_one_dev(skb, ethnl_ctx->req_info->dev,
+ ctx, genl_info_dump(cb));
+
+ if (ret < 0 && ret != -EOPNOTSUPP && likely(skb->len))
+ ret = skb->len;
+
+ netdev_put(ethnl_ctx->req_info->dev,
+ &ethnl_ctx->req_info->dev_tracker);
+ } else {
+ ret = ethnl_perphy_dump_all_dev(skb, ctx, genl_info_dump(cb));
+ }
+
+ return ret;
+}
+
+/* perphy ->done() handler for GET requests */
+static int ethnl_perphy_done(struct netlink_callback *cb)
+{
+ struct ethnl_perphy_dump_ctx *ctx = ethnl_perphy_dump_context(cb);
+ struct ethnl_dump_ctx *ethnl_ctx = &ctx->ethnl_ctx;
+
+ kfree(ethnl_ctx->reply_data);
+ kfree(ethnl_ctx->req_info);
+
+ return 0;
+}
+
/* default ->done() handler for GET requests */
static int ethnl_default_done(struct netlink_callback *cb)
{
@@ -1200,9 +1363,9 @@ static const struct genl_ops ethtool_genl_ops[] = {
{
.cmd = ETHTOOL_MSG_PSE_GET,
.doit = ethnl_default_doit,
- .start = ethnl_default_start,
- .dumpit = ethnl_default_dumpit,
- .done = ethnl_default_done,
+ .start = ethnl_perphy_start,
+ .dumpit = ethnl_perphy_dumpit,
+ .done = ethnl_perphy_done,
.policy = ethnl_pse_get_policy,
.maxattr = ARRAY_SIZE(ethnl_pse_get_policy) - 1,
},
@@ -1224,9 +1387,9 @@ static const struct genl_ops ethtool_genl_ops[] = {
{
.cmd = ETHTOOL_MSG_PLCA_GET_CFG,
.doit = ethnl_default_doit,
- .start = ethnl_default_start,
- .dumpit = ethnl_default_dumpit,
- .done = ethnl_default_done,
+ .start = ethnl_perphy_start,
+ .dumpit = ethnl_perphy_dumpit,
+ .done = ethnl_perphy_done,
.policy = ethnl_plca_get_cfg_policy,
.maxattr = ARRAY_SIZE(ethnl_plca_get_cfg_policy) - 1,
},
@@ -1240,9 +1403,9 @@ static const struct genl_ops ethtool_genl_ops[] = {
{
.cmd = ETHTOOL_MSG_PLCA_GET_STATUS,
.doit = ethnl_default_doit,
- .start = ethnl_default_start,
- .dumpit = ethnl_default_dumpit,
- .done = ethnl_default_done,
+ .start = ethnl_perphy_start,
+ .dumpit = ethnl_perphy_dumpit,
+ .done = ethnl_perphy_done,
.policy = ethnl_plca_get_status_policy,
.maxattr = ARRAY_SIZE(ethnl_plca_get_status_policy) - 1,
},
--
2.49.0