Re: [PATCH V6] ethdev: fix one address occupies two entries in MAC addrs

[Thomas Monjalon <thomas@monjalon.net>]

31/01/2023 07:41, Huisong Li:
> The dev->data->mac_addrs[0] will be changed to a new MAC address when
> applications modify the default MAC address by .mac_addr_set(). However,
> if the new default one has been added as a non-default MAC address by
> .mac_addr_add(), the .mac_addr_set() doesn't remove it from the mac_addrs
> list. As a result, one MAC address occupies two entries in the list. Like:
> add(MAC1)
> add(MAC2)
> add(MAC3)
> add(MAC4)
> set_default(MAC3)
> default=MAC3, the rest of list=MAC1, MAC2, MAC3, MAC4
> Note: MAC3 occupies two entries.
> 
> In addition, some PMDs, such as i40e, ice, hns3 and so on, do remove the
> old default MAC when set default MAC. If user continues to do
> set_default(MAC5), and the mac_addrs list is default=MAC5, filters=(MAC1,
> MAC2, MAC3, MAC4). At this moment, user can still see MAC3 from the list,
> but packets with MAC3 aren't actually received by the PMD.
> 
> So need to ensure that the new default address is removed from the rest of
> the list.
> 
> Fixes: 854d8ad4ef68 ("ethdev: add default mac address modifier")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Huisong Li <lihuisong@huawei.com>
> Acked-by: Chengwen Feng <fengchengwen@huawei.com>
> ---
>  lib/ethdev/ethdev_driver.h |  6 +++++-
>  lib/ethdev/rte_ethdev.c    | 35 +++++++++++++++++++++++++++++++++--
>  2 files changed, 38 insertions(+), 3 deletions(-)

This is a behavior change.
It must be noted in the release notes in the API section.

> -	/** Device Ethernet link address. @see rte_eth_dev_release_port() */
> +	/**
> +	 * Device Ethernet link addresses. The first entry (index zero) is the
> +	 * default address. The rest of list cannot be the same as the default
> +	 * address.
> +	 */

Please split the lines after a dot.

rest of "the" list

Maybe better for this field:
	All entries are unique.
	The first entry (index zero) is the default address.

>  	struct rte_ether_addr *mac_addrs;

and for the function rte_eth_dev_default_mac_addr_set:
	Set the default MAC address.
	It replaces the address at index 0 of the address list.
	If the address was already in the MAC address list,
	it is removed from the rest of the list.