linux-kernel - Re: [PATCH] net: ag71xx: remove dead code path

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Message-ID: <CAKxU2N-nLMn-VnR62xfuoJR2-1mtNTYQyLAiazpdmp89JSNndw@mail.gmail.com>
Date: Tue, 10 Sep 2024 11:22:32 -0700
From: Rosen Penev <rosenp@...il.com>
To: Qianqiang Liu <qianqiang.liu@....com>
Cc: chris.snook@...il.com, davem@...emloft.net, edumazet@...gle.com, 
	kuba@...nel.org, pabeni@...hat.com, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: ag71xx: remove dead code path

On Tue, Sep 10, 2024 at 8:30 AM Qianqiang Liu <qianqiang.liu@....com> wrote:
>
> The 'err' is always zero, so the following branch can never be executed:
> if (err) {
>         ndev->stats.rx_dropped++;
>         kfree_skb(skb);
> }
> Therefore, the 'if' statement can be removed.
>
> Signed-off-by: Qianqiang Liu <qianqiang.liu@....com>
Reviewed-by: Rosen Penev <rosenp@...il.com>

err was used downstream in OpenWrt when platform data was used. In the
transition to OF, the function was removed. Which was back in 2019 at
this point.
> ---
>  drivers/net/ethernet/atheros/ag71xx.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/atheros/ag71xx.c b/drivers/net/ethernet/atheros/ag71xx.c
> index 96a6189cc31e..5477f3f87e10 100644
> --- a/drivers/net/ethernet/atheros/ag71xx.c
> +++ b/drivers/net/ethernet/atheros/ag71xx.c
> @@ -1616,7 +1616,6 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
>                 unsigned int i = ring->curr & ring_mask;
>                 struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
>                 int pktlen;
> -               int err = 0;
>
>                 if (ag71xx_desc_empty(desc))
>                         break;
> @@ -1646,14 +1645,9 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
>                 skb_reserve(skb, offset);
>                 skb_put(skb, pktlen);
>
> -               if (err) {
> -                       ndev->stats.rx_dropped++;
> -                       kfree_skb(skb);
> -               } else {
> -                       skb->dev = ndev;
> -                       skb->ip_summed = CHECKSUM_NONE;
> -                       list_add_tail(&skb->list, &rx_list);
> -               }
> +               skb->dev = ndev;
> +               skb->ip_summed = CHECKSUM_NONE;
> +               list_add_tail(&skb->list, &rx_list);
>
>  next:
>                 ring->buf[i].rx.rx_buf = NULL;
> --
> 2.39.2
>
>