Re: [dpdk-dev] [PATCH 2/2] ethdev: fix VLAN offloads set if no relative capabilities

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 6/19/20 6:42 AM, Wei Hu (Xavier) wrote:
> From: Chengchang Tang <tangchengchang@huawei.com>
> 
> Currently, there is a potential problem that calling the API function
> rte_eth_dev_set_vlan_offload to start a vlan hardware offloads which the
> driver does not support. if the PMD driver does not support the relative
> hardware offloads and does not check for it, the hardware setting will
> not change, but the relative offload in dev->data->dev_conf.rxmode.offloads
> will be turned on.

I'm sorry, but I don't understand what 'relative' means in the
context.

Also, please, use 'VLAN' instead of 'vlan' in the description
and log message below.

> It is supposed to check the hardware capabilities to decide whether the
> relative callback needs to be called just like the behavior in the API
> function named rte_eth_dev_configure.

I think the direction of the fix is right, but it definitely
duplicates checks which are done in some PMDs. I think that it
would be good to do the cleanup in follow up patches.

> Fixes: 81f9db8ecc2c ("ethdev: add vlan offload support")

Most likely it is incorrect, since generic Rx offloads were
introduced later.

> Cc: stable@dpdk.org
> 
> Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
> Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
> ---
>  lib/librte_ethdev/rte_ethdev.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 122fd2a..5176a0e 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -3261,12 +3261,14 @@ rte_eth_dev_set_vlan_ether_type(uint16_t port_id,
>  int
>  rte_eth_dev_set_vlan_offload(uint16_t port_id, int offload_mask)
>  {
> +	struct rte_eth_dev_info dev_info;
>  	struct rte_eth_dev *dev;
>  	int ret = 0;
>  	int mask = 0;
>  	int cur, org = 0;
>  	uint64_t orig_offloads;
>  	uint64_t dev_offloads;
> +	uint64_t new_offloads;
>  
>  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>  	dev = &rte_eth_devices[port_id];
> @@ -3320,6 +3322,25 @@ rte_eth_dev_set_vlan_offload(uint16_t port_id, int offload_mask)
>  	if (mask == 0)
>  		return ret;
>  
> +	ret = rte_eth_dev_info_get(port_id, &dev_info);
> +	if (ret != 0)
> +		return ret;
> +
> +	/*
> +	 * New added Rx vlan offloading which are not enabled in
> +	 * rte_eth_dev_configure() must be within its device capabilities
> +	 */
> +	if ((dev_offloads & dev_info.rx_offload_capa) != dev_offloads) {
> +		new_offloads = dev_offloads & ~orig_offloads;
> +		RTE_ETHDEV_LOG(ERR,
> +			"Ethdev port_id=%u requested new added vlan offloads "
> +			"0x%" PRIx64 " must be within Rx offloads capabilities "
> +			"0x%"PRIx64 " in %s()\n",
> +			port_id, new_offloads, dev_info.rx_offload_capa,
> +			__func__);
> +		return -EINVAL;
> +	}
> +
>  	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->vlan_offload_set, -ENOTSUP);
>  	dev->data->dev_conf.rxmode.offloads = dev_offloads;
>  	ret = (*dev->dev_ops->vlan_offload_set)(dev, mask);
>