From:   David Laight <David.Laight@ACULAB.COM>
To:     'Pavel Begunkov' <asml.silence@gmail.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        "Jakub Kicinski" <kuba@kernel.org>
CC:     Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 13/14] net: inline part of skb_csum_hwoffload_help
Thread-Topic: [PATCH 13/14] net: inline part of skb_csum_hwoffload_help
Thread-Index: AQHYBooc+zd0TLCwI0SMx+giCPDt3axdi3LQ
Date:   Tue, 11 Jan 2022 09:24:49 +0000
Message-ID: <918a937f6cef44e282353001a7fbba7a@AcuMS.aculab.com>
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From: Pavel Begunkov
> Sent: 11 January 2022 01:22
> 
> Inline a HW csum'ed part of skb_csum_hwoffload_help().
> 
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>  include/linux/netdevice.h | 16 ++++++++++++++--
>  net/core/dev.c            | 13 +++----------
>  2 files changed, 17 insertions(+), 12 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 3213c7227b59..fbe6c764ce57 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -4596,8 +4596,20 @@ void netdev_rss_key_fill(void *buffer, size_t len);
> 
>  int skb_checksum_help(struct sk_buff *skb);
>  int skb_crc32c_csum_help(struct sk_buff *skb);
> -int skb_csum_hwoffload_help(struct sk_buff *skb,
> -			    const netdev_features_t features);
> +int __skb_csum_hwoffload_help(struct sk_buff *skb,
> +			      const netdev_features_t features);
> +
> +static inline int skb_csum_hwoffload_help(struct sk_buff *skb,
> +					  const netdev_features_t features)
> +{
> +	if (unlikely(skb_csum_is_sctp(skb)))
> +		return !!(features & NETIF_F_SCTP_CRC) ? 0 :

If that !! doing anything? - doesn't look like it.

> +			skb_crc32c_csum_help(skb);
> +
> +	if (features & NETIF_F_HW_CSUM)
> +		return 0;
> +	return __skb_csum_hwoffload_help(skb, features);
> +}

Maybe you should remove some bloat by moving the sctp code
into the called function.
This probably needs something like?

{
	if (features & NETIF_F_HW_CSUM && !skb_csum_is_sctp(skb))
		return 0;
	return __skb_csum_hw_offload(skb, features);
}

	David

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