Re: [PATCH iwl-next 1/1] igc: Allow hot-swapping XDP program

[Maciej Fijalkowski]

On Mon, Nov 18, 2024 at 12:15:45PM +0800, Song Yoong Siang wrote:
> Currently, the driver would always close and reopen the network interface
> when setting/removing the XDP program, regardless of the presence of XDP
> resources. This could cause unnecessary disruptions.
> 
> To avoid this, introduces a check to determine if there is a need to
> close and reopen the interface, allowing for seamless hot-swapping of
> XDP programs.
> 
> Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>

Acked-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>

> ---
>  drivers/net/ethernet/intel/igc/igc_xdp.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_xdp.c b/drivers/net/ethernet/intel/igc/igc_xdp.c
> index e27af72aada8..869815f48ac1 100644
> --- a/drivers/net/ethernet/intel/igc/igc_xdp.c
> +++ b/drivers/net/ethernet/intel/igc/igc_xdp.c
> @@ -13,6 +13,7 @@ int igc_xdp_set_prog(struct igc_adapter *adapter, struct bpf_prog *prog,
>  	struct net_device *dev = adapter->netdev;
>  	bool if_running = netif_running(dev);
>  	struct bpf_prog *old_prog;
> +	bool need_update;
>  
>  	if (dev->mtu > ETH_DATA_LEN) {
>  		/* For now, the driver doesn't support XDP functionality with
> @@ -22,7 +23,8 @@ int igc_xdp_set_prog(struct igc_adapter *adapter, struct bpf_prog *prog,
>  		return -EOPNOTSUPP;
>  	}
>  
> -	if (if_running)
> +	need_update = !!adapter->xdp_prog != !!prog;
> +	if (if_running && need_update)
>  		igc_close(dev);
>  
>  	old_prog = xchg(&adapter->xdp_prog, prog);
> @@ -34,7 +36,7 @@ int igc_xdp_set_prog(struct igc_adapter *adapter, struct bpf_prog *prog,
>  	else
>  		xdp_features_clear_redirect_target(dev);
>  
> -	if (if_running)
> +	if (if_running && need_update)
>  		igc_open(dev);
>  
>  	return 0;
> -- 
> 2.34.1
> 
>