[RFC][b/azure][PATCH 3/3] net: core: support XDP generic on stacked devices.

[Connor Kuehl]

On 6/13/19 1:24 PM, Ioanna Alifieraki wrote:
> From: Stephen Hemminger <stephen at networkplumber.org>
> 
> BugLink: https://bugs.launchpad.net/bugs/1831254
> 
> When a device is stacked like (team, bonding, failsafe or netvsc) the
> XDP generic program for the parent device was not called.
> 
> Move the call to XDP generic inside __netif_receive_skb_core where
> it can be done multiple times for stacked case.
> 
> Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices")
> Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (backported from commit 458bf2f224f04a513b0be972f8708e78ee2c986e)
> [Hunks 4 and 5 in oringinal commit modify netif_receive_skb_list_internal
> function which is not present, so do not remove them.]

Should this say "so remove them" instead of "so do not remove them"?

> Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki at canonical.com>
> ---
>  net/core/dev.c | 42 ++++++++++++------------------------------
>  1 file changed, 12 insertions(+), 30 deletions(-)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 99f62b724d6e..901b558cce5c 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4198,23 +4198,6 @@ static int netif_rx_internal(struct sk_buff *skb)
>  
>  	trace_netif_rx(skb);
>  
> -	if (static_branch_unlikely(&generic_xdp_needed_key)) {
> -		int ret;
> -
> -		preempt_disable();
> -		rcu_read_lock();
> -		ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
> -		rcu_read_unlock();
> -		preempt_enable();
> -
> -		/* Consider XDP consuming the packet a success from
> -		 * the netdev point of view we do not want to count
> -		 * this as an error.
> -		 */
> -		if (ret != XDP_PASS)
> -			return NET_RX_SUCCESS;
> -	}
> -
>  #ifdef CONFIG_RPS
>  	if (static_branch_unlikely(&rps_needed)) {
>  		struct rps_dev_flow voidflow, *rflow = &voidflow;
> @@ -4543,6 +4526,18 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
>  
>  	__this_cpu_inc(softnet_data.processed);
>  
> +	if (static_branch_unlikely(&generic_xdp_needed_key)) {
> +		int ret2;
> +
> +		preempt_disable();
> +		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
> +		preempt_enable();
> +
> +		if (ret2 != XDP_PASS)
> +			return NET_RX_DROP;
> +		skb_reset_mac_len(skb);
> +	}
> +
>  	if (skb->protocol == cpu_to_be16(ETH_P_8021Q) ||
>  	    skb->protocol == cpu_to_be16(ETH_P_8021AD)) {
>  		skb = skb_vlan_untag(skb);
> @@ -4760,19 +4755,6 @@ static int netif_receive_skb_internal(struct sk_buff *skb)
>  	if (skb_defer_rx_timestamp(skb))
>  		return NET_RX_SUCCESS;
>  
> -	if (static_branch_unlikely(&generic_xdp_needed_key)) {
> -		int ret;
> -
> -		preempt_disable();
> -		rcu_read_lock();
> -		ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
> -		rcu_read_unlock();
> -		preempt_enable();
> -
> -		if (ret != XDP_PASS)
> -			return NET_RX_DROP;
> -	}
> -
>  	rcu_read_lock();
>  #ifdef CONFIG_RPS
>  	if (static_branch_unlikely(&rps_needed)) {
> 


-- 
Connor
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