Re: [dpdk-dev] [PATCH v6 2/2] ethdev: fix VLAN offloads set if no relative capabilities

[Thomas Monjalon <thomas@monjalon.net>]

09/07/2020 09:39, Wei Hu (Xavier):
> On 2020/7/8 18:14, Thomas Monjalon wrote:
> > 08/07/2020 05:37, Wei Hu (Xavier):
> >> On 2020/7/7 22:11, Thomas Monjalon wrote:
> >>> 06/07/2020 09:06, Wei Hu (Xavier):
> >>>> Currently, there is a potential problem that calling the API function
> >>>> rte_eth_dev_set_vlan_offload to start VLAN hardware offloads which the
> >>>> driver does not support. If the PMD driver does not support certain VLAN
> >>>> hardware offloads and does not check for it, the hardware setting will
> >>>> not change, but the VLAN offloads in dev->data->dev_conf.rxmode.offloads
> >>>> will be turned on.
> >>>>
> >>>> 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. And it is also needed to cleanup
> >>>> duplicated checks which are done in some PMDs. Also, note that it is
> >>>> behaviour change for some PMDs which simply ignore (with error/warning log
> >>>> message) unsupported VLAN offloads, but now it will fail.
> > [...]
> >>>> @@ -3317,6 +3319,25 @@ 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
> >>>> +	 */
> >>> What means "New added Rx VLAN offloading"?
> >> The parameter offload_mask of rte_eth_dev_set_vlan_offload() function
> >> includes some Rx VLAN offload, and some of them maybe are not enabled
> >> in rte_eth_dev_configure().
> > OK
> >
> > I don't understand why checking only new features.
> > All enabled features must be within capabilities, right?
> Yes，you are right. all enabled features must be within capabilities，
> Some features enabled in rte_eth_dev_configure() had been already checked,
> So the comment here emphasizes 'new added Rx VLAN offloading'.

I feel this precision more confusing than helpful.