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[PATCH net-next 1/7] net: ethtool: netlink: Allow per-netdevice DUMP operations

Maxime Chevallier posted 7 patches 11 months, 1 week ago
There is a newer version of this series
[PATCH net-next 1/7] net: ethtool: netlink: Allow per-netdevice DUMP operations
Posted by Maxime Chevallier 11 months, 1 week ago 
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>
---
 net/ethtool/netlink.c | 45 ++++++++++++++++++++++++++++---------------
 net/ethtool/netlink.h |  1 +
 2 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 734849a57369..0815b28ba32f 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -578,21 +578,34 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
 	int ret = 0;
 
 	rcu_read_lock();
-	for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
-		dev_hold(dev);
+	if (ctx->req_info->dev) {
+		dev = ctx->req_info->dev;
 		rcu_read_unlock();
-
-		ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
-
+		/* Filtered DUMP request targeted to a single netdev. We already
+		 * hold a ref to the netdev from ->start()
+		 */
+		ret = ethnl_default_dump_one_dev(skb, dev, ctx,
+						 genl_info_dump(cb));
 		rcu_read_lock();
-		dev_put(dev);
-
-		if (ret < 0 && ret != -EOPNOTSUPP) {
-			if (likely(skb->len))
-				ret = skb->len;
-			break;
+		netdev_put(ctx->req_info->dev, &ctx->req_info->dev_tracker);
+	} else {
+		for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
+			dev_hold(dev);
+			rcu_read_unlock();
+
+			ret = ethnl_default_dump_one(skb, dev, ctx,
+						     genl_info_dump(cb));
+
+			rcu_read_lock();
+			dev_put(dev);
+
+			if (ret < 0 && ret != -EOPNOTSUPP) {
+				if (likely(skb->len))
+					ret = skb->len;
+				break;
+			}
+			ret = 0;
 		}
-		ret = 0;
 	}
 	rcu_read_unlock();
 
@@ -626,10 +639,10 @@ 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..4db27182741f 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -388,6 +388,7 @@ 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
Re: [PATCH net-next 1/7] net: ethtool: netlink: Allow per-netdevice DUMP operations
Posted by Simon Horman 11 months, 1 week ago 
On Wed, Mar 05, 2025 at 03:19:31PM +0100, Maxime Chevallier wrote:
> 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>
> ---
>  net/ethtool/netlink.c | 45 ++++++++++++++++++++++++++++---------------
>  net/ethtool/netlink.h |  1 +
>  2 files changed, 30 insertions(+), 16 deletions(-)
> 
> diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> index 734849a57369..0815b28ba32f 100644
> --- a/net/ethtool/netlink.c
> +++ b/net/ethtool/netlink.c
> @@ -578,21 +578,34 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
>  	int ret = 0;
>  
>  	rcu_read_lock();
> -	for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> -		dev_hold(dev);
> +	if (ctx->req_info->dev) {
> +		dev = ctx->req_info->dev;
>  		rcu_read_unlock();
> -
> -		ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
> -
> +		/* Filtered DUMP request targeted to a single netdev. We already
> +		 * hold a ref to the netdev from ->start()
> +		 */
> +		ret = ethnl_default_dump_one_dev(skb, dev, ctx,
> +						 genl_info_dump(cb));

Hi Maxime,

ethnl_default_dump_one_dev() is called here but it doesn't exist
until the following patch is applied, which breaks bisection.

>  		rcu_read_lock();
> -		dev_put(dev);
> -
> -		if (ret < 0 && ret != -EOPNOTSUPP) {
> -			if (likely(skb->len))
> -				ret = skb->len;
> -			break;
> +		netdev_put(ctx->req_info->dev, &ctx->req_info->dev_tracker);
> +	} else {
> +		for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> +			dev_hold(dev);
> +			rcu_read_unlock();
> +
> +			ret = ethnl_default_dump_one(skb, dev, ctx,
> +						     genl_info_dump(cb));
> +
> +			rcu_read_lock();
> +			dev_put(dev);
> +
> +			if (ret < 0 && ret != -EOPNOTSUPP) {
> +				if (likely(skb->len))
> +					ret = skb->len;
> +				break;
> +			}
> +			ret = 0;
>  		}
> -		ret = 0;
>  	}
>  	rcu_read_unlock();
>  

...

> diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
> index ec6ab5443a6f..4db27182741f 100644
> --- a/net/ethtool/netlink.h
> +++ b/net/ethtool/netlink.h
> @@ -388,6 +388,7 @@ struct ethnl_request_ops {
>  	unsigned int		req_info_size;
>  	unsigned int		reply_data_size;
>  	bool			allow_nodev_do;
> +	bool			allow_pernetdev_dump;

nit: allow_pernetdev_dump should also be added to the Kernel doc for
     struct ethnl_request_ops

     Flagged by ./scripts/kernel-doc -none

     There also appear to be similar minor issues with subsequent
     patches in this series.

>  	u8			set_ntf_cmd;
>  
>  	int (*parse_request)(struct ethnl_req_info *req_info,
> -- 
> 2.48.1
>
Re: [PATCH net-next 1/7] net: ethtool: netlink: Allow per-netdevice DUMP operations
Posted by Maxime Chevallier 11 months, 1 week ago 
Hi Simon,

On Fri, 7 Mar 2025 12:21:19 +0000
Simon Horman <horms@kernel.org> wrote:

> On Wed, Mar 05, 2025 at 03:19:31PM +0100, Maxime Chevallier wrote:
> > 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>
> > ---
> >  net/ethtool/netlink.c | 45 ++++++++++++++++++++++++++++---------------
> >  net/ethtool/netlink.h |  1 +
> >  2 files changed, 30 insertions(+), 16 deletions(-)
> > 
> > diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> > index 734849a57369..0815b28ba32f 100644
> > --- a/net/ethtool/netlink.c
> > +++ b/net/ethtool/netlink.c
> > @@ -578,21 +578,34 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
> >  	int ret = 0;
> >  
> >  	rcu_read_lock();
> > -	for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> > -		dev_hold(dev);
> > +	if (ctx->req_info->dev) {
> > +		dev = ctx->req_info->dev;
> >  		rcu_read_unlock();
> > -
> > -		ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
> > -
> > +		/* Filtered DUMP request targeted to a single netdev. We already
> > +		 * hold a ref to the netdev from ->start()
> > +		 */
> > +		ret = ethnl_default_dump_one_dev(skb, dev, ctx,
> > +						 genl_info_dump(cb));  
> 
> Hi Maxime,
> 
> ethnl_default_dump_one_dev() is called here but it doesn't exist
> until the following patch is applied, which breaks bisection.

Yeah I messed-up in my rebase and bisection broke :(

I'll send a new version in a few days, as Jakub said, let's give some
time for the netdev_lock series to move forward and go through CI, I'll
need to rebase on it at some point.

> 
> >  		rcu_read_lock();
> > -		dev_put(dev);
> > -
> > -		if (ret < 0 && ret != -EOPNOTSUPP) {
> > -			if (likely(skb->len))
> > -				ret = skb->len;
> > -			break;
> > +		netdev_put(ctx->req_info->dev, &ctx->req_info->dev_tracker);
> > +	} else {
> > +		for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> > +			dev_hold(dev);
> > +			rcu_read_unlock();
> > +
> > +			ret = ethnl_default_dump_one(skb, dev, ctx,
> > +						     genl_info_dump(cb));
> > +
> > +			rcu_read_lock();
> > +			dev_put(dev);
> > +
> > +			if (ret < 0 && ret != -EOPNOTSUPP) {
> > +				if (likely(skb->len))
> > +					ret = skb->len;
> > +				break;
> > +			}
> > +			ret = 0;
> >  		}
> > -		ret = 0;
> >  	}
> >  	rcu_read_unlock();
> >    
> 
> ...
> 
> > diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
> > index ec6ab5443a6f..4db27182741f 100644
> > --- a/net/ethtool/netlink.h
> > +++ b/net/ethtool/netlink.h
> > @@ -388,6 +388,7 @@ struct ethnl_request_ops {
> >  	unsigned int		req_info_size;
> >  	unsigned int		reply_data_size;
> >  	bool			allow_nodev_do;
> > +	bool			allow_pernetdev_dump;  
> 
> nit: allow_pernetdev_dump should also be added to the Kernel doc for
>      struct ethnl_request_ops
> 
>      Flagged by ./scripts/kernel-doc -none
> 
>      There also appear to be similar minor issues with subsequent
>      patches in this series.

Ack, I'll make sure the doc is up to date and properly formatted :)

Thanks,

Maxime

> >  	u8			set_ntf_cmd;
> >  
> >  	int (*parse_request)(struct ethnl_req_info *req_info,
> > -- 
> > 2.48.1
> >
Re: [PATCH net-next 1/7] net: ethtool: netlink: Allow per-netdevice DUMP operations
Posted by Simon Horman 11 months, 1 week ago 
On Fri, Mar 07, 2025 at 02:18:19PM +0100, Maxime Chevallier wrote:
> Hi Simon,
> 
> On Fri, 7 Mar 2025 12:21:19 +0000
> Simon Horman <horms@kernel.org> wrote:
> 
> > On Wed, Mar 05, 2025 at 03:19:31PM +0100, Maxime Chevallier wrote:
> > > 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>
> > > ---
> > >  net/ethtool/netlink.c | 45 ++++++++++++++++++++++++++++---------------
> > >  net/ethtool/netlink.h |  1 +
> > >  2 files changed, 30 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> > > index 734849a57369..0815b28ba32f 100644
> > > --- a/net/ethtool/netlink.c
> > > +++ b/net/ethtool/netlink.c
> > > @@ -578,21 +578,34 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
> > >  	int ret = 0;
> > >  
> > >  	rcu_read_lock();
> > > -	for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> > > -		dev_hold(dev);
> > > +	if (ctx->req_info->dev) {
> > > +		dev = ctx->req_info->dev;
> > >  		rcu_read_unlock();
> > > -
> > > -		ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
> > > -
> > > +		/* Filtered DUMP request targeted to a single netdev. We already
> > > +		 * hold a ref to the netdev from ->start()
> > > +		 */
> > > +		ret = ethnl_default_dump_one_dev(skb, dev, ctx,
> > > +						 genl_info_dump(cb));  
> > 
> > Hi Maxime,
> > 
> > ethnl_default_dump_one_dev() is called here but it doesn't exist
> > until the following patch is applied, which breaks bisection.
> 
> Yeah I messed-up in my rebase and bisection broke :(
> 
> I'll send a new version in a few days, as Jakub said, let's give some
> time for the netdev_lock series to move forward and go through CI, I'll
> need to rebase on it at some point.

Thanks. Apologies for duplicating Jakub's comments to some extent.
I only saw them after I'd sent my previous email to you.

...

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