Subject: Re: [PATCH net-next 17/22] hv_netvsc: fix return type of ndo_start_xmit function

From: Stephen Hemminger <[email-masked]>
Date: Thu, 20 Sep 2018 07:43:41 -0700

On Thu, 20 Sep 2018 20:33:01 +0800
YueHaibing <[email-masked]> wrote:

> The method ndo_start_xmit() is defined as returning an 'netdev_tx_t',
> which is a typedef for an enum type, so make sure the implementation in
> this driver has returns 'netdev_tx_t' value, and change the function
> return type to netdev_tx_t.
> 
> Found by coccinelle.
> 
> Signed-off-by: YueHaibing <[email-masked]>
> ---
>  drivers/net/hyperv/netvsc_drv.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 3af6d8d..056c472 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -511,7 +511,8 @@ static int netvsc_vf_xmit(struct net_device *net, struct net_device *vf_netdev,
>  	return rc;
>  }
>  
> -static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
> +static netdev_tx_t
> +netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
>  {
>  	struct net_device_context *net_device_ctx = netdev_priv(net);
>  	struct hv_netvsc_packet *packet = NULL;
> @@ -528,8 +529,11 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
>  	 */
>  	vf_netdev = rcu_dereference_bh(net_device_ctx->vf_netdev);
>  	if (vf_netdev && netif_running(vf_netdev) &&
> -	    !netpoll_tx_running(net))
> -		return netvsc_vf_xmit(net, vf_netdev, skb);
> +	    !netpoll_tx_running(net)) {
> +		ret = netvsc_vf_xmit(net, vf_netdev, skb);
> +		if (ret)
> +			return NETDEV_TX_BUSY;
> +	}

Sorry, the new code is wrong. It will fall through if ret == 0 (NETDEV_TX_OK)
Please review and test your patches.