[PATCH] examples/vdpa: fix disabled VirtQ statistics query

[Xia, Chenbo]

Hi Xueming,

> -----Original Message-----
> From: Xueming Li <xuemingl at nvidia.com>
> Sent: Thursday, February 24, 2022 9:24 PM
> To: dev at dpdk.org
> Cc: xuemingl at nvidia.com; stable at dpdk.org; Maxime Coquelin
> <maxime.coquelin at redhat.com>; Xia, Chenbo <chenbo.xia at intel.com>; Matan Azrad
> <matan at mellanox.com>
> Subject: [PATCH] examples/vdpa: fix disabled VirtQ statistics query
> 
> Quit VirtQ statistics query instead of reporting error.
> 
> Fixes: 6505865aa8ed ("examples/vdpa: add statistics show command")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Xueming Li <xuemingl at nvidia.com>
> ---
>  examples/vdpa/main.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
> index 5ab07655aed..bd66deca85c 100644
> --- a/examples/vdpa/main.c
> +++ b/examples/vdpa/main.c
> @@ -391,7 +391,9 @@ static void cmd_device_stats_parsed(void *parsed_result,
> struct cmdline *cl,
>  	struct rte_vdpa_device *vdev = rte_vdpa_find_device_by_name(res->bdf);
>  	struct vdpa_port *vport = NULL;
>  	uint32_t first, last;
> +	int vq_disabled = -1;
>  	int i;
> +	int ret;
> 
>  	if (!vdev) {
>  		RTE_LOG(ERR, VDPA, "Invalid device: %s.\n",
> @@ -449,8 +451,20 @@ static void cmd_device_stats_parsed(void *parsed_result,
> struct cmdline *cl,
>  	cmdline_printf(cl, "\nDevice %s:\n", res->bdf);
>  	for (; first <= last; first++) {
>  		memset(vport->stats, 0, sizeof(*vport->stats) * vport->stats_n);
> -		if (rte_vdpa_get_stats(vport->dev, (int)first, vport->stats,
> -					vport->stats_n) <= 0) {
> +		ret = rte_vdpa_get_stats(vport->dev, (int)first, vport->stats,
> +						vport->stats_n);
> +		if (ret == 0) {
> +			/* VQ disabled. */
> +			if (vq_disabled == -1)
> +				vq_disabled = (int)first;
> +			continue;

I am not sure. Does ret == 0 mean VQ is disabled in this API? Because I don't see 
anything special described in API doxygen about return value equals zero.

> +		}
> +		if (vq_disabled != -1) {
> +			cmdline_printf(cl, "\tVirtq %d - %d disabled\n",
> +				       vq_disabled, (int)first - 1);

Let's check if vq_disabled == first - 1 to make different log. I will feel strange
if I see log like 'Virq 2-2 disabled'.

Thanks,
Chenbo

> +			vq_disabled = -1;
> +		}
> +		if (ret < 0) {
>  			RTE_LOG(ERR, VDPA, "Failed to get vdpa queue statistics"
>  				" for device %s qid %d.\n", res->bdf,
>  				(int)first);
> @@ -464,6 +478,9 @@ static void cmd_device_stats_parsed(void *parsed_result,
> struct cmdline *cl,
>  				vport->stats[i].value);
>  		}
>  	}
> +	if (vq_disabled != -1)
> +		cmdline_printf(cl, "\tVirtq %d - %d disabled\n",
> +			       vq_disabled, (int)first - 1);
>  }
> 
>  cmdline_parse_token_string_t cmd_device_stats_ =
> --
> 2.35.1