[PATCH net-next v4 2/8] net: ethtool: netlink: Allow per-netdevice DUMP operations
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2025-03-24 10:40:26
Also in:
linux-arm-kernel, lkml
Subsystem:
networking [ethtool], networking [general], the rest · Maintainers:
Andrew Lunn, Jakub Kicinski, "David S. Miller", Eric Dumazet, Paolo Abeni, Linus Torvalds
We have a number of netlink commands in the ethnl family that may have
multiple objects to dump even for a single net_device, including :
- PLCA, PSE-PD, phy: one message per PHY device
- tsinfo: one message per timestamp source (netdev + phys)
- rss: One per RSS context
To get this behaviour, these netlink commands need to roll a custom
->dumpit().
To prepare making per-netdev DUMP more generic in ethnl, introduce a
member in the ethnl ops to indicate if a given command may allow
pernetdev DUMPs (also referred to as filtered DUMPs).
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
V4: - Don't hold RCU in the filtered path
- Move dump_all into a new separate helper
net/ethtool/netlink.c | 37 ++++++++++++++++++++++++++++++-------
net/ethtool/netlink.h | 2 ++
2 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 6b1725795435..31ab89ca0bcc 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c@@ -577,9 +577,7 @@ static int ethnl_default_dump_one(struct sk_buff *skb, struct net_device *dev, return ret; } -/* Default ->dumpit() handler for GET requests. */ -static int ethnl_default_dumpit(struct sk_buff *skb, - struct netlink_callback *cb) +static int ethnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) { struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb); struct net *net = sock_net(skb->sk);
@@ -609,6 +607,31 @@ static int ethnl_default_dumpit(struct sk_buff *skb, return ret; } +/* Default ->dumpit() handler for GET requests. */ +static int ethnl_default_dumpit(struct sk_buff *skb, + struct netlink_callback *cb) +{ + struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb); + int ret; + + if (ctx->req_info->dev) { + /* Filtered DUMP request targeted to a single netdev. We already + * hold a ref to the netdev from ->start() + */ + ret = ethnl_default_dump_one(skb, ctx->req_info->dev, ctx, + genl_info_dump(cb)); + netdev_put(ctx->req_info->dev, &ctx->req_info->dev_tracker); + + if (ret < 0 && ret != -EOPNOTSUPP && likely(skb->len)) + ret = skb->len; + + } else { + ret = ethnl_dump_all(skb, cb); + } + + return ret; +} + /* generic ->start() handler for GET requests */ static int ethnl_default_start(struct netlink_callback *cb) {
@@ -636,10 +659,10 @@ static int ethnl_default_start(struct netlink_callback *cb) } ret = ethnl_default_parse(req_info, &info->info, ops, false); - if (req_info->dev) { - /* We ignore device specification in dump requests but as the - * same parser as for non-dump (doit) requests is used, it - * would take reference to the device if it finds one + if (req_info->dev && !ops->allow_pernetdev_dump) { + /* We ignore device specification in unfiltered dump requests + * but as the same parser as for non-dump (doit) requests is + * used, it would take reference to the device if it finds one */ netdev_put(req_info->dev, &req_info->dev_tracker); req_info->dev = NULL;
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index ec6ab5443a6f..4aaa73282d6a 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h@@ -331,6 +331,7 @@ int ethnl_sock_priv_set(struct sk_buff *skb, struct net_device *dev, u32 portid, * @req_info_size: size of request info * @reply_data_size: size of reply data * @allow_nodev_do: allow non-dump request with no device identification + * @allow_pernetdev_dump: allow filtering dump requests with ifname/ifindex * @set_ntf_cmd: notification to generate on changes (SET) * @parse_request: * Parse request except common header (struct ethnl_req_info). Common
@@ -388,6 +389,7 @@ struct ethnl_request_ops { unsigned int req_info_size; unsigned int reply_data_size; bool allow_nodev_do; + bool allow_pernetdev_dump; u8 set_ntf_cmd; int (*parse_request)(struct ethnl_req_info *req_info,
--
2.48.1