Re: [net-next,v16,07/12] virtio_net: Implement layer 2 ethtool flow rules

[Jakub Kicinski <kuba@kernel.org>]

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---
virtio_net: Implement layer 2 ethtool flow rules

This patch adds ethtool flow rule support for ethernet headers,
implementing classifier and rule management via virtio admin commands.

> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index b406f5f1c75e..e3f2a7e0e99f 100644

[ ... ]

> +static int build_and_insert(struct virtnet_ff *ff,
> +			    struct virtnet_ethtool_rule *eth_rule)
> +{
> +	struct virtio_net_resource_obj_ff_classifier *classifier;
> +	struct ethtool_rx_flow_spec *fs = &eth_rule->flow_spec;
> +	struct virtio_net_ff_selector *selector;
> +	struct virtnet_classifier *c;
> +	size_t classifier_size;
> +	int num_hdrs;
> +	u8 key_size;
> +	u8 *key;
> +	int err;
> +
> +	calculate_flow_sizes(fs, &key_size, &classifier_size, &num_hdrs);
> +
> +	key = kzalloc(key_size, GFP_KERNEL);
> +	if (!key)
> +		return -ENOMEM;
> +
> +	/*
> +	 * virtio_net_ff_obj_ff_classifier is already included in the
> +	 * classifier_size.
> +	 */
> +	c = kzalloc(classifier_size +
> +		    sizeof(struct virtnet_classifier) -
> +		    sizeof(struct virtio_net_resource_obj_ff_classifier),
> +		    GFP_KERNEL);
> +	if (!c) {
> +		kfree(key);
> +		return -ENOMEM;
> +	}
> +
> +	c->size = classifier_size;
> +	classifier = &c->classifier;
> +	classifier->count = num_hdrs;
> +	selector = (void *)&classifier->selectors[0];
> +
> +	setup_eth_hdr_key_mask(selector, key, fs);
> +
> +	err = validate_classifier_selectors(ff, classifier, num_hdrs);
> +	if (err)
> +		goto err_key;
                  ^^^^^^

If validate_classifier_selectors() fails, this jumps to err_key which
only frees key but not c. Should this be goto err_classifier instead,
to avoid leaking the struct virtnet_classifier allocation?

> +
> +	err = setup_classifier(ff, c);
> +	if (err)
> +		goto err_classifier;
> +
> +	err = insert_rule(ff, eth_rule, c->id, key, key_size);
> +	if (err) {
> +		/* destroy_classifier will free the classifier */
> +		destroy_classifier(ff, c->id);
> +		goto err_key;
> +	}
> +
> +	return 0;
> +
> +err_classifier:
> +	kfree(c);
> +err_key:
> +	kfree(key);
> +
> +	return err;
> +}