Re: [PATCH V5] ethdev: fix one address occupies two indexes in MAC addrs

[Thomas Monjalon <thomas@monjalon.net>]

18/01/2023 09:26, Thomas Monjalon:
> 20/10/2022 11:31, 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 indexes in the list. Like:
> > add(MAC1)
> > add(MAC2)
> > add(MAC3)
> > add(MAC4)
> > set_default(MAC3)
> > default=MAC3, filters=MAC1, MAC2, MAC3, MAC4
> 
> I agree it may be simpler to ensure that the addresses are uniques.
> 
> > 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.
> 
> If MAC3 is not removed with rte_eth_dev_mac_addr_remove() by the app,
> MAC3 packets should be received.
> The MAC address should not be removed by the PMD.

Sorry for the confusion. I mean the opposite.
With the new behavior, if we want the old default address to be kept
in the list, we need to add it explicitly with rte_eth_dev_mac_addr_add.
This is a behavior change and must be highlighted in the release notes.

> > So this patch adds a remove operation in set default MAC API documents
> > this behavior.
> 
> Let's be clear here: only the new default address is removed from the rest of the list.
> 
> > Fixes: 854d8ad4ef68 ("ethdev: add default mac address modifier")
> > Cc: stable@dpdk.org
> 
> > --- a/lib/ethdev/ethdev_driver.h
> > +++ b/lib/ethdev/ethdev_driver.h
> > @@ -116,7 +116,12 @@ struct rte_eth_dev_data {
> >  
> >  	uint64_t rx_mbuf_alloc_failed; /**< Rx ring mbuf allocation failures */
> >  
> > -	/** Device Ethernet link address. @see rte_eth_dev_release_port() */
> > +	/**
> > +	 * Device Ethernet link address. The index zero of the array is as the
> 
> It should be "addresses" as there can be multiple.
> 
> What means "as" above?
> Can we say the first entry (index zero) is the default address?
> 
> > +	 * index of the default address, and other indexes can't be the same
> 
> You can split the sentence in 2 instead of ", and".
> indexes -> entries
> can't -> cannot
> 
> > +	 * as the address corresponding to index 0.
> 
> simpler: as the default address.
> 
> > +	 * @see rte_eth_dev_release_port()
> 
> Why referencing this function here?
> 
> > +	 */
> 
> > --- a/lib/ethdev/rte_ethdev.c
> > +++ b/lib/ethdev/rte_ethdev.c
> > @@ -4498,7 +4498,10 @@ rte_eth_dev_mac_addr_remove(uint16_t port_id, struct rte_ether_addr *addr)
> >  int
> >  rte_eth_dev_default_mac_addr_set(uint16_t port_id, struct rte_ether_addr *addr)
> >  {
> > +	uint64_t mac_pool_sel_bk = 0;
> >  	struct rte_eth_dev *dev;
> > +	uint32_t pool;
> > +	int index;
> >  	int ret;
> >  
> >  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > @@ -4517,16 +4520,50 @@ rte_eth_dev_default_mac_addr_set(uint16_t port_id, struct rte_ether_addr *addr)
> >  	if (*dev->dev_ops->mac_addr_set == NULL)
> >  		return -ENOTSUP;
> >  
> > +	/*
> > +	 * If the address has been added as a non-default MAC address by
> > +	 * rte_eth_dev_mac_addr_add API, it should be removed from
> > +	 * dev->data->mac_addrs[].
> > +	 */
> 
> Make is simpler:
> "Keep address unique in dev->data->mac_addrs[]."
> 
> > +	index = eth_dev_get_mac_addr_index(port_id, addr);
> > +	if (index > 0) {
> > +		/* Remove address in dev data structure */
> > +		mac_pool_sel_bk = dev->data->mac_pool_sel[index];
> > +		ret = rte_eth_dev_mac_addr_remove(port_id, addr);
> > +		if (ret < 0) {
> > +			RTE_ETHDEV_LOG(ERR, "Delete MAC address from the MAC list of ethdev port %u.\n",
> > +				       port_id);
> 
> It is not clear with this log that it failed.
> 
> > +			return ret;
> > +		}
> > +		/* Reset pool bitmap */
> > +		dev->data->mac_pool_sel[index] = 0;
> 
> mac_pool_sel[index] is already reset in rte_eth_dev_mac_addr_remove().
> 
> > +	}
> >  	ret = (*dev->dev_ops->mac_addr_set)(dev, addr);
> >  	if (ret < 0)
> > -		return ret;
> > +		goto out;
> >  
> >  	/* Update default address in NIC data structure */
> >  	rte_ether_addr_copy(addr, &dev->data->mac_addrs[0]);
> >  
> >  	return 0;
> > -}
> >  
> > +out:
> > +	if (index > 0) {
> > +		pool = 0;
> > +		do {
> > +			if (mac_pool_sel_bk & UINT64_C(1)) {
> > +				if (rte_eth_dev_mac_addr_add(port_id, addr,
> > +							     pool) != 0)
> > +					RTE_ETHDEV_LOG(ERR, "failed to restore MAC pool id(%u) in port %u.\n",
> > +						       pool, port_id);
> > +			}
> > +			mac_pool_sel_bk >>= 1;
> > +			pool++;
> > +		} while (mac_pool_sel_bk != 0);
> > +	}
> > +
> > +	return ret;
> > +}
> 
> Can we avoid this rollback by removing the address after mac_addr_set() succeed?