Subject: Re: [PATCH net-next v12 07/12] virtio_net: Implement layer 2 ethtool flow rules

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 25 Nov 2025 09:25:32 -0500

On Wed, Nov 19, 2025 at 01:15:18PM -0600, Daniel Jurgens wrote:
> +static int virtnet_ethtool_flow_insert(struct virtnet_ff *ff,
> +				       struct ethtool_rx_flow_spec *fs,
> +				       u16 curr_queue_pairs)
> +{
> +	struct virtnet_ethtool_rule *eth_rule;
> +	int err;
> +
> +	if (!ff->ff_supported)
> +		return -EOPNOTSUPP;
> +
> +	err = validate_flow_input(ff, fs, curr_queue_pairs);
> +	if (err)
> +		return err;
> +
> +	eth_rule = kzalloc(sizeof(*eth_rule), GFP_KERNEL);
> +	if (!eth_rule)
> +		return -ENOMEM;
> +
> +	err = xa_alloc(&ff->ethtool.rules, &fs->location, eth_rule,
> +		       XA_LIMIT(0, le32_to_cpu(ff->ff_caps->rules_limit) - 1),
> +		       GFP_KERNEL);
> +	if (err)
> +		goto err_rule;
> +
> +	eth_rule->flow_spec = *fs;
> +
> +	err = build_and_insert(ff, eth_rule);
> +	if (err)
> +		goto err_xa;

btw kind of inelegant that we change fs->location if build_and_insert fails.
restore it?

> +	return err;
> +
> +err_xa:
> +	xa_erase(&ff->ethtool.rules, eth_rule->flow_spec.location);
> +
> +err_rule:
> +	fs->location = RX_CLS_LOC_ANY;
> +	kfree(eth_rule);
> +
> +	return err;
> +}