Re: [dpdk-dev] [PATCH] net/i40e: fix FDIR check programming status error

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Zhao1, Wei
> Sent: Wednesday, July 11, 2018 4:25 PM
> To: dev@dpdk.org
> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; stable@dpdk.org; Zhao1, Wei
> <wei.zhao1@intel.com>
> Subject: [PATCH] net/i40e: fix FDIR check programming status error
> 
> In i40e FDIR PMD code for checking programming status function
> i40e_check_fdir_programming_status(), the initial value of return value ret
> should be set to -1 not 0, because if DD bit of I40E_RX_DESC_STATUS_DD is not
> write back, this function will return
> 0 to upper function, this give an error info to upper function, the fact for this is
> it is time out for DD write back and it should return -1.
> 
> Fixes: 05999aab4ca6 ("i40e: add or delete flow director")
> Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
> ---
>  drivers/net/i40e/i40e_fdir.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/i40e/i40e_fdir.c b/drivers/net/i40e/i40e_fdir.c index
> d41601a..b958bf6 100644
> --- a/drivers/net/i40e/i40e_fdir.c
> +++ b/drivers/net/i40e/i40e_fdir.c
> @@ -1315,7 +1315,7 @@ i40e_check_fdir_programming_status(struct
> i40e_rx_queue *rxq)
>  	uint32_t rx_status;
>  	uint32_t len, id;
>  	uint32_t error;
> -	int ret = 0;
> +	int ret = -1;
> 
>  	rxdp = &rxq->rx_ring[rxq->rx_tail];
>  	qword1 = rte_le_to_cpu_64(rxdp->wb.qword1.status_error_len);
> @@ -1360,6 +1360,7 @@ i40e_check_fdir_programming_status(struct
> i40e_rx_queue *rxq)
>  			I40E_PCI_REG_WRITE(rxq->qrx_tail, rxq->nb_rx_desc - 1);
>  		else
>  			I40E_PCI_REG_WRITE(rxq->qrx_tail, rxq->rx_tail - 1);
> +		ret = 0;

Is it possible to overwrite previous ret = -1 which is not what we want?

I would prefer

int ret = 0;

If (dd bit is set) {
	If xxx
		Ret = -1;
	If xxx 
		Ret = -1;
} else {
	ret = -1;
}

return ret;

>  	}
> 
>  	return ret;
> --
> 2.7.5