RE: [PATCH net-next,1/2] hv_netvsc: Fix the return status in RX path

[Michael Kelley (EOSG)]

> -----Original Message-----
> From: linux-kernel-owner@xxxxxxxxxxxxxxx <linux-kernel-owner@xxxxxxxxxxxxxxx> On Behalf
> Of Haiyang Zhang
> Sent: Thursday, March 22, 2018 12:01 PM
> To: davem@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>; Stephen
> Hemminger <sthemmin@xxxxxxxxxxxxx>; olaf@xxxxxxxxx; vkuznets@xxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH net-next,1/2] hv_netvsc: Fix the return status in RX path
> 
> From: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> 
> As defined in hyperv_net.h, the NVSP_STAT_SUCCESS is one not zero.
> Some functions returns 0 when it actually means NVSP_STAT_SUCCESS.
> This patch fixes them.
> 
> In netvsc_receive(), it puts the last RNDIS packet's receive status
> for all packets in a vmxferpage which may contain multiple RNDIS
> packets.
> This patch puts NVSP_STAT_FAIL in the receive completion if one of
> the packets in a vmxferpage fails.

This patch changes the status field that is being reported back to
the Hyper-V host in the receive completion message in
enq_receive_complete().   The current code reports 0 on success,
and with the patch, it will report 1 on success.  So does this change
affect anything on the Hyper-V side?  Or is Hyper-V just ignoring
the value?   If this change doesn't have any impact on the
interactions with Hyper-V, perhaps it would be good to explain
why in the commit message.

Michael

> 
> Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> ---
>  drivers/net/hyperv/netvsc.c       | 8 ++++++--
>  drivers/net/hyperv/netvsc_drv.c   | 2 +-
>  drivers/net/hyperv/rndis_filter.c | 4 ++--
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index aa95e81af6e5..1ddb2c39b6e4 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -1098,12 +1098,16 @@ static int netvsc_receive(struct net_device *ndev,
>  		void *data = recv_buf
>  			+ vmxferpage_packet->ranges[i].byte_offset;
>  		u32 buflen = vmxferpage_packet->ranges[i].byte_count;
> +		int ret;
> 
>  		trace_rndis_recv(ndev, q_idx, data);
> 
>  		/* Pass it to the upper layer */
> -		status = rndis_filter_receive(ndev, net_device,
> -					      channel, data, buflen);
> +		ret = rndis_filter_receive(ndev, net_device,
> +					   channel, data, buflen);
> +
> +		if (unlikely(ret != NVSP_STAT_SUCCESS))
> +			status = NVSP_STAT_FAIL;
>  	}
> 
>  	enq_receive_complete(ndev, net_device, q_idx,
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index cdb78eefab67..33607995be62 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -818,7 +818,7 @@ int netvsc_recv_callback(struct net_device *net,
>  	u64_stats_update_end(&rx_stats->syncp);
> 
>  	napi_gro_receive(&nvchan->napi, skb);
> -	return 0;
> +	return NVSP_STAT_SUCCESS;
>  }
> 
>  static void netvsc_get_drvinfo(struct net_device *net,
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index 2dc00f714482..591fb8080f11 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -443,10 +443,10 @@ int rndis_filter_receive(struct net_device *ndev,
>  			"unhandled rndis message (type %u len %u)\n",
>  			   rndis_msg->ndis_msg_type,
>  			   rndis_msg->msg_len);
> -		break;
> +		return NVSP_STAT_FAIL;
>  	}
> 
> -	return 0;
> +	return NVSP_STAT_SUCCESS;
>  }
> 
>  static int rndis_filter_query_device(struct rndis_device *dev,
> --
> 2.15.1