Subject: Re: [PATCH net-next 2/3] iavf: fix err handling for MAC replace

From: Maciej Fijalkowski <[email-masked]>
Date: Mon, 5 Jun 2023 21:17:28 +0200

On Fri, Jun 02, 2023 at 10:13:01AM -0700, Tony Nguyen wrote:
> From: Przemek Kitszel <[email-masked]>
> 
> Defer removal of current primary MAC until a replacement is successfully added.
> Previous implementation would left filter list with no primary MAC.

and this opens up for what kind of issues? do you mean that
iavf_add_filter() could break and existing primary filter has been marked
for removal?

> This was found while reading the code.
> 
> The patch takes advantage of the fact that there can only be a single primary
> MAC filter at any time.
> 
> Signed-off-by: Przemek Kitszel <[email-masked]>
> Signed-off-by: Piotr Gardocki <[email-masked]>
> Reviewed-by: Michal Swiatkowski <[email-masked]>
> Tested-by: Rafal Romanowski <[email-masked]>
> Signed-off-by: Tony Nguyen <[email-masked]>
> ---
>  drivers/net/ethernet/intel/iavf/iavf_main.c | 42 ++++++++++-----------
>  1 file changed, 19 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
> index 420aaca548a0..3a78f86ba4f9 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_main.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
> @@ -1010,40 +1010,36 @@ int iavf_replace_primary_mac(struct iavf_adapter *adapter,

from what i'm looking at, iavf_replace_primary_mac() could be scoped only
to iavf_main.c and become static func.

>  			     const u8 *new_mac)
>  {
>  	struct iavf_hw *hw = &adapter->hw;
> -	struct iavf_mac_filter *f;
> +	struct iavf_mac_filter *new_f;
> +	struct iavf_mac_filter *old_f;
>  
>  	spin_lock_bh(&adapter->mac_vlan_list_lock);
>  
> -	list_for_each_entry(f, &adapter->mac_filter_list, list) {
> -		f->is_primary = false;
> +	new_f = iavf_add_filter(adapter, new_mac);
> +	if (!new_f) {
> +		spin_unlock_bh(&adapter->mac_vlan_list_lock);
> +		return -ENOMEM;
>  	}
>  
> -	f = iavf_find_filter(adapter, hw->mac.addr);
> -	if (f) {
> -		f->remove = true;
> +	old_f = iavf_find_filter(adapter, hw->mac.addr);
> +	if (old_f) {
> +		old_f->is_primary = false;
> +		old_f->remove = true;
>  		adapter->aq_required |= IAVF_FLAG_AQ_DEL_MAC_FILTER;
>  	}
> -
> -	f = iavf_add_filter(adapter, new_mac);
> -
> -	if (f) {
> -		/* Always send the request to add if changing primary MAC
> -		 * even if filter is already present on the list
> -		 */
> -		f->is_primary = true;
> -		f->add = true;
> -		adapter->aq_required |= IAVF_FLAG_AQ_ADD_MAC_FILTER;
> -		ether_addr_copy(hw->mac.addr, new_mac);
> -	}
> +	/* Always send the request to add if changing primary MAC,
> +	 * even if filter is already present on the list
> +	 */
> +	new_f->is_primary = true;
> +	new_f->add = true;
> +	adapter->aq_required |= IAVF_FLAG_AQ_ADD_MAC_FILTER;
> +	ether_addr_copy(hw->mac.addr, new_mac);
>  
>  	spin_unlock_bh(&adapter->mac_vlan_list_lock);
>  
>  	/* schedule the watchdog task to immediately process the request */
> -	if (f) {
> -		mod_delayed_work(adapter->wq, &adapter->watchdog_task, 0);
> -		return 0;
> -	}
> -	return -ENOMEM;
> +	mod_delayed_work(adapter->wq, &adapter->watchdog_task, 0);
> +	return 0;
>  }
>  
>  /**
> -- 
> 2.38.1
> 
>