netdev - Re: [PATCH net-next] sh_eth: remove open coded netif

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Date:   Wed, 22 Mar 2023 23:54:42 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        <netdev@...r.kernel.org>
CC:     <linux-renesas-soc@...r.kernel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next] sh_eth: remove open coded netif_running()

On 3/21/23 9:58 AM, Wolfram Sang wrote:

> It had a purpose back in the days, but today we have a handy helper.

   Well, the is_opened flag doesn't get set/cleared at the same time as
__LINK_STATE_START. I'm not sure they are interchangeable...
 
> Reported-by: Geert Uytterhoeven <geert+renesas@...der.be>
> Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> ---
> 
> Based on 6.3-rc3 and tested on a Renesas Lager board (R-Car H2).
> 
>  drivers/net/ethernet/renesas/sh_eth.c | 6 +-----
>  drivers/net/ethernet/renesas/sh_eth.h | 1 -
>  2 files changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
> index d8ec729825be..2d9787231099 100644
> --- a/drivers/net/ethernet/renesas/sh_eth.c
> +++ b/drivers/net/ethernet/renesas/sh_eth.c
> @@ -2441,8 +2441,6 @@ static int sh_eth_open(struct net_device *ndev)
>  
>  	netif_start_queue(ndev);
>  
> -	mdp->is_opened = 1;
> -

   __LINK_STATE_START gets set before the ndo_open() method call, so
before the RPM call that enbales the clocks...

>  	return ret;
>  
>  out_free_irq:
> @@ -2565,7 +2563,7 @@ static struct net_device_stats *sh_eth_get_stats(struct net_device *ndev)
>  	if (mdp->cd->no_tx_cntrs)
>  		return &ndev->stats;
>  
> -	if (!mdp->is_opened)
> +	if (!netif_running(ndev))
>  		return &ndev->stats;

   I guess mdp->is_opened is checked here to avoid reading the counter
regs when RPM hasn't been called yet to enable the clocks...

[...]

MBR, Sergey