Re: [PATCH net-next v2 18/21] net: ravb: Return cached statistics if the interface is down

[Sergey Shtylyov]

On 12/14/23 2:45 PM, Claudiu wrote:

> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> 
> Return the cached statistics in case the interface is down. There should be
> no drawback to this, as most of the statistics are updated on the data path
> and if runtime PM is enabled and the interface is down, the registers that
> are explicitly read on ravb_get_stats() are zero anyway on most of the IP
> variants.
> 
> The commit prepares the code for the addition of runtime PM support.
> 
> Suggested-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> ---
> 
> Changes in v2:
> - none; this patch is new
> 
>  drivers/net/ethernet/renesas/ravb_main.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index a2a64c22ec41..1995cf7ff084 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2110,6 +2110,9 @@ static struct net_device_stats *ravb_get_stats(struct net_device *ndev)
>  	const struct ravb_hw_info *info = priv->info;
>  	struct net_device_stats *nstats, *stats0, *stats1;
>  
> +	if (!netif_running(ndev))

   I'm afraid this is racy as __LINK_STATE_START bit gets set
by __dev_open() before calling the ndo_open() method... :-(

> +		return &ndev->stats;
> +

   The sh_eth driver calls sh_eth_get_stats() from sh_eth_dev_exit();
perhaps it's worth doing something similar?

MBR, Sergey