linux-kernel - Re: [PATCH net-next] net: hns3: remove unnecessary NULL checking in napi_consume

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Date:   Sat, 19 Sep 2020 10:23:26 +0800
From:   Yunsheng Lin <linyunsheng@...wei.com>
To:     <davem@...emloft.net>, <kuba@...nel.org>, <linmiaohe@...wei.com>,
        <martin.varghese@...ia.com>, <fw@...len.de>, <edumazet@...gle.com>,
        <dcaratti@...hat.com>, <steffen.klassert@...unet.com>,
        <pabeni@...hat.com>, <kyk.segfault@...il.com>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linuxarm@...wei.com>
Subject: Re: [PATCH net-next] net: hns3: remove unnecessary NULL checking in
 napi_consume_skb()

Please ignore this patch, the title is not right, sorry for the noise.

On 2020/9/19 10:16, Yunsheng Lin wrote:
> When budget is non-zero, skb_unref() has already handled the
> NULL checking.
> 
> When budget is zero, the dev_consume_skb_any() has handled NULL
> checking in __dev_kfree_skb_irq(), or dev_kfree_skb() which also
> ultimately call skb_unref().
> 
> So remove the unnecessary checking in napi_consume_skb().
> 
> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
> ---
>  net/core/skbuff.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index bfd7483..e077447 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -895,9 +895,6 @@ void __kfree_skb_defer(struct sk_buff *skb)
>  
>  void napi_consume_skb(struct sk_buff *skb, int budget)
>  {
> -	if (unlikely(!skb))
> -		return;
> -
>  	/* Zero budget indicate non-NAPI context called us, like netpoll */
>  	if (unlikely(!budget)) {
>  		dev_consume_skb_any(skb);
>