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

[Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>]

> -----Original Message-----
> From: YueHaibing <yuehaibing@xxxxxxxxxx>
> Sent: Thursday, September 20, 2018 8:33 AM
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> YueHaibing <yuehaibing@xxxxxxxxxx>
> Subject: [PATCH net-next 17/22] hv_netvsc: fix return type of ndo_start_xmit
> function
> 
> 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 <yuehaibing@xxxxxxxxxx>
> ---
>  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;

For error case, please just return NETDEV_TX_OK. We are not sure if the 
error can go away after retrying, returning NETDEV_TX_BUSY may cause 
infinite retry from the upper layer.

Thanks,
- Haiyang

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