Re: [dpdk-dev] [PATCH] i40evf: fix return value if command fails

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, May 05, 2016 at 02:22:54PM +0800, Jingjing Wu wrote:
> Previously, if message is sent successfully, but no response is
> received, function "i40evf_execute_vf_cmd" will return without error.
> The root cause is value "err" is overwritten. This patch fixes it.
> 
> Fixes: ae19955e7c86 ("i40evf: support reporting PF reset")
> Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
> ---
>  drivers/net/i40e/i40e_ethdev_vf.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
> index 2bce69b..9380019 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -327,8 +327,7 @@ i40evf_execute_vf_cmd(struct rte_eth_dev *dev, struct vf_cmd_info *args)
>  	struct i40e_vf *vf = I40EVF_DEV_PRIVATE_TO_VF(dev->data->dev_private);
>  	struct i40evf_arq_msg_info info;
>  	enum i40evf_aq_result ret;
> -	int err = -1;
> -	int i = 0;
> +	int err, i = 0;
>  
>  	if (_atomic_set_cmd(vf, args->ops))
>  		return -1;
> @@ -346,6 +345,7 @@ i40evf_execute_vf_cmd(struct rte_eth_dev *dev, struct vf_cmd_info *args)
>  		return err;
>  	}
>  
> +	err = -1;
>  	switch (args->ops) {
>  	case I40E_VIRTCHNL_OP_RESET_VF:
>  		/*no need to process in this function */

Hi Jingjing,

this patch changes this return value in this case (I40E_VIRTCHNL_OP_RESET_VF).
Is this intentional - if so it probably needs to be documented in the commit
message. If not, the "err = -1" should be put at the start of the do { } while
loop for the GET_VF_RESOURCES command.

Perhaps to avoid future errors, each case in the switch should explicitly set
it's own default error value?

/Bruce