[dpdk-dev] replay MAC address in rte_eth_dev_config_restore()

Ferruh Yigit ferruh.yigit at intel.com
Wed Jan 18 19:39:11 CET 2017

On 1/18/2017 4:12 AM, Steve Shin (jonshin) wrote:
> Hi,
> I have a question on MAC address replay logic in rte_eth_dev_config_restore():
> lib/librte_ether/rte_ethdev.c:
> code snippet of rte_eth_dev_config_restore()
> ~~
>         /* replay MAC address configuration */
>         for (i = 0; i < dev_info.max_mac_addrs; i++) {
>                 addr = dev->data->mac_addrs[i];
>                 /* skip zero address */
>                 if (is_zero_ether_addr(&addr))
>                         continue;
>                 /* add address to the hardware */
>                 if  (*dev->dev_ops->mac_addr_add &&
>                         (dev->data->mac_pool_sel[i] & (1ULL << pool)))
>                         (*dev->dev_ops->mac_addr_add)(dev, &addr, i, pool);
>                 else {
>                         RTE_PMD_DEBUG_TRACE("port %d: MAC address array not supported\n",
>                                         port_id);
>                         /* exit the loop but not return an error */
>                         break;
>                 }
>         }
> dev->data->mac_addrs[0] is filled with a HW MAC address (by default) when a device is initialized. But there’s no flag setting for dev->data->mac_pool_sel[0].
> As the value of “(dev->data->mac_pool_sel[i] & (1ULL << pool)) “ becomes 0 for i=0, the replay logic will be stopped without processing the rest of MAC addresses in dev->data->mac_addrs[] list.
> Shouldn’t ‘break’ statement be replaced with ‘continue’ to process other MACs in the list?

Hi Steve,

Looks like you are right. The commit that pool check added (4bdefaad) says:
Fix bug in rte_eth_dev_config_restore function, which will restore all
MAC address to default pool.
So intention looks like not stop adding mac_addr loop if mac is not in
pool, but instead not adding a mac address if it is not part of pool.

But pool check seems added later, and initial "break" is added for
"dev_ops->mac_addr_add" check.

Logic can be:

if (dev_ops->mac_addr_add)
	if (mac in pool)

But of course, instead of checking the dev_ops in a loop for same
device, it makes more sense to remove it out of loop.

Are you planning to send a patch for this issue?
It is easier to discuss code based on patches..

> Any feedback would be appreciated.
> Regards,
> Steve

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