Add the dump_one_dev callback to ethnl_request_ops, allowing commands
to provide custom per-device dump logic with sub-positioning. Extend
ethnl_dump_ctx with ifindex and pos_sub fields.
No functional change; no command uses dump_one_dev yet.
Signed-off-by: Björn Töpel <bjorn@kernel.org>
---
net/ethtool/netlink.c | 66 ++++++++++++++++++-------------------------
net/ethtool/netlink.h | 31 ++++++++++++++++++++
2 files changed, 58 insertions(+), 39 deletions(-)
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 5046023a30b1..8d161f0882d0 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -346,36 +346,6 @@ int ethnl_multicast(struct sk_buff *skb, struct net_device *dev)
/* GET request helpers */
-/**
- * struct ethnl_dump_ctx - context structure for generic dumpit() callback
- * @ops: request ops of currently processed message type
- * @req_info: parsed request header of processed request
- * @reply_data: data needed to compose the reply
- * @pos_ifindex: saved iteration position - ifindex
- *
- * These parameters are kept in struct netlink_callback as context preserved
- * between iterations. They are initialized by ethnl_default_start() and used
- * in ethnl_default_dumpit() and ethnl_default_done().
- */
-struct ethnl_dump_ctx {
- const struct ethnl_request_ops *ops;
- struct ethnl_req_info *req_info;
- struct ethnl_reply_data *reply_data;
- unsigned long pos_ifindex;
-};
-
-/**
- * struct ethnl_perphy_dump_ctx - context for dumpit() PHY-aware callbacks
- * @ethnl_ctx: generic ethnl context
- * @ifindex: For Filtered DUMP requests, the ifindex of the targeted netdev
- * @pos_phyindex: iterator position for multi-msg DUMP
- */
-struct ethnl_perphy_dump_ctx {
- struct ethnl_dump_ctx ethnl_ctx;
- unsigned int ifindex;
- unsigned long pos_phyindex;
-};
-
static const struct ethnl_request_ops *
ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
[ETHTOOL_MSG_STRSET_GET] = ðnl_strset_request_ops,
@@ -618,6 +588,7 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
struct netlink_callback *cb)
{
struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb);
+ const struct genl_info *info = genl_info_dump(cb);
struct net *net = sock_net(skb->sk);
netdevice_tracker dev_tracker;
struct net_device *dev;
@@ -625,10 +596,20 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
rcu_read_lock();
for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
+ if (ctx->ifindex && ctx->ifindex != ctx->pos_ifindex)
+ break;
+
netdev_hold(dev, &dev_tracker, GFP_ATOMIC);
rcu_read_unlock();
- ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
+ if (ctx->ops->dump_one_dev) {
+ ctx->req_info->dev = dev;
+ ret = ctx->ops->dump_one_dev(skb, ctx, &ctx->pos_sub,
+ info);
+ ctx->req_info->dev = NULL;
+ } else {
+ ret = ethnl_default_dump_one(skb, dev, ctx, info);
+ }
rcu_read_lock();
netdev_put(dev, &dev_tracker);
@@ -674,19 +655,26 @@ static int ethnl_default_start(struct netlink_callback *cb)
ret = ethnl_default_parse(req_info, &info->info, ops, false);
if (ret < 0)
goto free_reply_data;
- 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
- */
- netdev_put(req_info->dev, &req_info->dev_tracker);
- req_info->dev = NULL;
- }
ctx->ops = ops;
ctx->req_info = req_info;
ctx->reply_data = reply_data;
ctx->pos_ifindex = 0;
+ ctx->ifindex = 0;
+ ctx->pos_sub = 0;
+
+ if (req_info->dev) {
+ if (ops->dump_one_dev) {
+ /* Sub-iterator dumps keep track of the dev's ifindex
+ * so the dumpit handler can grab/release the netdev
+ * per iteration.
+ */
+ ctx->ifindex = req_info->dev->ifindex;
+ ctx->pos_ifindex = ctx->ifindex;
+ }
+ netdev_put(req_info->dev, &req_info->dev_tracker);
+ req_info->dev = NULL;
+ }
return 0;
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index aaf6f2468768..e01adc5db02f 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -10,6 +10,28 @@
struct ethnl_req_info;
+/**
+ * struct ethnl_dump_ctx - context structure for generic dumpit() callback
+ * @ops: request ops of currently processed message type
+ * @req_info: parsed request header of processed request
+ * @reply_data: data needed to compose the reply
+ * @pos_ifindex: saved iteration position - ifindex
+ * @ifindex: for filtered dump requests, the ifindex of the targeted netdev
+ * @pos_sub: iterator position for per-device iteration
+ *
+ * These parameters are kept in struct netlink_callback as context preserved
+ * between iterations. They are initialized by ethnl_default_start() and used
+ * in ethnl_default_dumpit() and ethnl_default_done().
+ */
+struct ethnl_dump_ctx {
+ const struct ethnl_request_ops *ops;
+ struct ethnl_req_info *req_info;
+ struct ethnl_reply_data *reply_data;
+ unsigned long pos_ifindex;
+ unsigned int ifindex;
+ unsigned long pos_sub;
+};
+
u32 ethnl_bcast_seq_next(void);
int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info,
const struct nlattr *nest, struct net *net,
@@ -365,6 +387,10 @@ int ethnl_sock_priv_set(struct sk_buff *skb, struct net_device *dev, u32 portid,
* used e.g. to free any additional data structures outside the main
* structure which were allocated by ->prepare_data(). When processing
* dump requests, ->cleanup() is called for each message.
+ * @dump_one_dev:
+ * Optional callback for dumping data for a single device. When set,
+ * overrides the default dump behavior for GET requests, allowing
+ * per-device iteration with sub-positioning via @pos_sub.
* @set_validate:
* Check if set operation is supported for a given device, and perform
* extra input checks. Expected return values:
@@ -409,6 +435,11 @@ struct ethnl_request_ops {
const struct ethnl_reply_data *reply_data);
void (*cleanup_data)(struct ethnl_reply_data *reply_data);
+ int (*dump_one_dev)(struct sk_buff *skb,
+ struct ethnl_dump_ctx *ctx,
+ unsigned long *pos_sub,
+ const struct genl_info *info);
+
int (*set_validate)(struct ethnl_req_info *req_info,
struct genl_info *info);
int (*set)(struct ethnl_req_info *req_info,
--
2.53.0
Hi Björn,
On 25/03/2026 15:50, Björn Töpel wrote:
> Add the dump_one_dev callback to ethnl_request_ops, allowing commands
> to provide custom per-device dump logic with sub-positioning. Extend
> ethnl_dump_ctx with ifindex and pos_sub fields.
>
> No functional change; no command uses dump_one_dev yet.
>
> Signed-off-by: Björn Töpel <bjorn@kernel.org>
Awesome :) I confirm that the phy dump still works just fine, and this
looks much simpler to me.
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Maxime
> ---
> net/ethtool/netlink.c | 66 ++++++++++++++++++-------------------------
> net/ethtool/netlink.h | 31 ++++++++++++++++++++
> 2 files changed, 58 insertions(+), 39 deletions(-)
>
> diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> index 5046023a30b1..8d161f0882d0 100644
> --- a/net/ethtool/netlink.c
> +++ b/net/ethtool/netlink.c
> @@ -346,36 +346,6 @@ int ethnl_multicast(struct sk_buff *skb, struct net_device *dev)
>
> /* GET request helpers */
>
> -/**
> - * struct ethnl_dump_ctx - context structure for generic dumpit() callback
> - * @ops: request ops of currently processed message type
> - * @req_info: parsed request header of processed request
> - * @reply_data: data needed to compose the reply
> - * @pos_ifindex: saved iteration position - ifindex
> - *
> - * These parameters are kept in struct netlink_callback as context preserved
> - * between iterations. They are initialized by ethnl_default_start() and used
> - * in ethnl_default_dumpit() and ethnl_default_done().
> - */
> -struct ethnl_dump_ctx {
> - const struct ethnl_request_ops *ops;
> - struct ethnl_req_info *req_info;
> - struct ethnl_reply_data *reply_data;
> - unsigned long pos_ifindex;
> -};
> -
> -/**
> - * struct ethnl_perphy_dump_ctx - context for dumpit() PHY-aware callbacks
> - * @ethnl_ctx: generic ethnl context
> - * @ifindex: For Filtered DUMP requests, the ifindex of the targeted netdev
> - * @pos_phyindex: iterator position for multi-msg DUMP
> - */
> -struct ethnl_perphy_dump_ctx {
> - struct ethnl_dump_ctx ethnl_ctx;
> - unsigned int ifindex;
> - unsigned long pos_phyindex;
> -};
> -
> static const struct ethnl_request_ops *
> ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
> [ETHTOOL_MSG_STRSET_GET] = ðnl_strset_request_ops,
> @@ -618,6 +588,7 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
> struct netlink_callback *cb)
> {
> struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb);
> + const struct genl_info *info = genl_info_dump(cb);
> struct net *net = sock_net(skb->sk);
> netdevice_tracker dev_tracker;
> struct net_device *dev;
> @@ -625,10 +596,20 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
>
> rcu_read_lock();
> for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> + if (ctx->ifindex && ctx->ifindex != ctx->pos_ifindex)
> + break;
> +
> netdev_hold(dev, &dev_tracker, GFP_ATOMIC);
> rcu_read_unlock();
>
> - ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
> + if (ctx->ops->dump_one_dev) {
> + ctx->req_info->dev = dev;
> + ret = ctx->ops->dump_one_dev(skb, ctx, &ctx->pos_sub,
> + info);
> + ctx->req_info->dev = NULL;
> + } else {
> + ret = ethnl_default_dump_one(skb, dev, ctx, info);
> + }
>
> rcu_read_lock();
> netdev_put(dev, &dev_tracker);
> @@ -674,19 +655,26 @@ static int ethnl_default_start(struct netlink_callback *cb)
> ret = ethnl_default_parse(req_info, &info->info, ops, false);
> if (ret < 0)
> goto free_reply_data;
> - 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
> - */
> - netdev_put(req_info->dev, &req_info->dev_tracker);
> - req_info->dev = NULL;
> - }
>
> ctx->ops = ops;
> ctx->req_info = req_info;
> ctx->reply_data = reply_data;
> ctx->pos_ifindex = 0;
> + ctx->ifindex = 0;
> + ctx->pos_sub = 0;
> +
> + if (req_info->dev) {
> + if (ops->dump_one_dev) {
> + /* Sub-iterator dumps keep track of the dev's ifindex
> + * so the dumpit handler can grab/release the netdev
> + * per iteration.
> + */
> + ctx->ifindex = req_info->dev->ifindex;
> + ctx->pos_ifindex = ctx->ifindex;
> + }
> + netdev_put(req_info->dev, &req_info->dev_tracker);
> + req_info->dev = NULL;
> + }
>
> return 0;
>
> diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
> index aaf6f2468768..e01adc5db02f 100644
> --- a/net/ethtool/netlink.h
> +++ b/net/ethtool/netlink.h
> @@ -10,6 +10,28 @@
>
> struct ethnl_req_info;
>
> +/**
> + * struct ethnl_dump_ctx - context structure for generic dumpit() callback
> + * @ops: request ops of currently processed message type
> + * @req_info: parsed request header of processed request
> + * @reply_data: data needed to compose the reply
> + * @pos_ifindex: saved iteration position - ifindex
> + * @ifindex: for filtered dump requests, the ifindex of the targeted netdev
> + * @pos_sub: iterator position for per-device iteration
> + *
> + * These parameters are kept in struct netlink_callback as context preserved
> + * between iterations. They are initialized by ethnl_default_start() and used
> + * in ethnl_default_dumpit() and ethnl_default_done().
> + */
> +struct ethnl_dump_ctx {
> + const struct ethnl_request_ops *ops;
> + struct ethnl_req_info *req_info;
> + struct ethnl_reply_data *reply_data;
> + unsigned long pos_ifindex;
> + unsigned int ifindex;
> + unsigned long pos_sub;
> +};
> +
> u32 ethnl_bcast_seq_next(void);
> int ethnl_parse_header_dev_get(struct ethnl_req_info *req_info,
> const struct nlattr *nest, struct net *net,
> @@ -365,6 +387,10 @@ int ethnl_sock_priv_set(struct sk_buff *skb, struct net_device *dev, u32 portid,
> * used e.g. to free any additional data structures outside the main
> * structure which were allocated by ->prepare_data(). When processing
> * dump requests, ->cleanup() is called for each message.
> + * @dump_one_dev:
> + * Optional callback for dumping data for a single device. When set,
> + * overrides the default dump behavior for GET requests, allowing
> + * per-device iteration with sub-positioning via @pos_sub.
> * @set_validate:
> * Check if set operation is supported for a given device, and perform
> * extra input checks. Expected return values:
> @@ -409,6 +435,11 @@ struct ethnl_request_ops {
> const struct ethnl_reply_data *reply_data);
> void (*cleanup_data)(struct ethnl_reply_data *reply_data);
>
> + int (*dump_one_dev)(struct sk_buff *skb,
> + struct ethnl_dump_ctx *ctx,
> + unsigned long *pos_sub,
> + const struct genl_info *info);
> +
> int (*set_validate)(struct ethnl_req_info *req_info,
> struct genl_info *info);
> int (*set)(struct ethnl_req_info *req_info,
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