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

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

[Stephen Hemminger]

On Thu, 20 Sep 2018 20:33:01 +0800
YueHaibing <yuehaibing@huawei.com> 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 <yuehaibing@huawei.com>
> ---
>  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.

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

[YueHaibing]

On 2018/9/20 22:43, Stephen Hemminger wrote:
> On Thu, 20 Sep 2018 20:33:01 +0800
> YueHaibing <yuehaibing@huawei.com> 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 <yuehaibing@huawei.com>
>> ---
>>  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.

I'm sorry for this, will correct it as Haiyang's suggestion.

> 
> .
>

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

[Haiyang Zhang]

> -----Original Message-----
> From: YueHaibing <yuehaibing@huawei.com>
> Sent: Thursday, September 20, 2018 8:33 AM
> To: davem@davemloft.net; dmitry.tarnyagin@lockless.no;
> wg@grandegger.com; mkl@pengutronix.de; michal.simek@xilinx.com;
> hsweeten@visionengravers.com; madalin.bucur@nxp.com;
> pantelis.antoniou@gmail.com; claudiu.manoil@nxp.com; leoyang.li@nxp.com;
> linux@armlinux.org.uk; sammy@sammy.net; ralf@linux-mips.org;
> nico@fluxnic.net; steve.glendinning@shawell.net; f.fainelli@gmail.com;
> grygorii.strashko@ti.com; w-kwok2@ti.com; m-karicheri2@ti.com;
> t.sailer@alumni.ethz.ch; jreuter@yaina.de; KY Srinivasan <kys@microsoft.com>;
> Haiyang Zhang <haiyangz@microsoft.com>; wei.liu2@citrix.com;
> paul.durrant@citrix.com; arvid.brodin@alten.se; pshelar@ovn.org
> Cc: linux-kernel@vger.kernel.org; netdev@vger.kernel.org; linux-
> can@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linuxppc-
> dev@lists.ozlabs.org; linux-mips@linux-mips.org; linux-omap@vger.kernel.org;
> linux-hams@vger.kernel.org; devel@linuxdriverproject.org; linux-
> usb@vger.kernel.org; xen-devel@lists.xenproject.org; dev@openvswitch.org;
> YueHaibing <yuehaibing@huawei.com>
> 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@huawei.com>
> ---
>  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

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

[YueHaibing]

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@huawei.com>
---
 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;
+	}
 
 	/* We will atmost need two pages to describe the rndis
 	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number