From: Vladimir Oltean <olteanv@gmail.com>
To: Eric Dumazet <edumazet@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, netdev <netdev@vger.kernel.org>,
David Laight <David.Laight@aculab.com>
Subject: Re: [PATCH net-next 2/2] net: optimize skb_postpull_rcsum()
Date: Thu, 2 Dec 2021 23:07:05 +0200 [thread overview]
Message-ID: <20211202210705.vsqr67svt3sm53h3@skbuf> (raw)
In-Reply-To: <CANn89iJOH0QtRhDfBzJr3fpJPNCQJhbMqT_8sa+vH_6mmZ7xhw@mail.gmail.com>
On Thu, Dec 02, 2021 at 12:37:35PM -0800, Eric Dumazet wrote:
> On Thu, Dec 2, 2021 at 11:32 AM Eric Dumazet <edumazet@google.com> wrote:
> >
> > Thanks Vladimir
> >
> > I think that maybe the issue is that the initial skb->csum is zero,
> > and the csum_parttial(removed_block) is also zero.
> >
> > But the initial skb->csum should not be zero if you have a non " all
> > zero" frame.
> >
> > Can you double check this in drivers/net/ethernet/freescale/enetc/enetc.c ?
>
> Yes, I am not sure why the csum is inverted in enetc_get_offloads()
I guess it's inverted because the hardware doesn't provide its one's
complement.
> Perhaps
>
> diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c
> b/drivers/net/ethernet/freescale/enetc/enetc.c
> index 504e12554079e306e477b9619f272d6e96527377..72524f14cae0093763f8a3f57b1e08e31bc4df1a
> 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc.c
> @@ -986,7 +986,7 @@ static void enetc_get_offloads(struct enetc_bdr *rx_ring,
> if (rx_ring->ndev->features & NETIF_F_RXCSUM) {
> u16 inet_csum = le16_to_cpu(rxbd->r.inet_csum);
>
> - skb->csum = csum_unfold((__force __sum16)~htons(inet_csum));
> + skb->csum = csum_unfold((__force __sum16)htons(inet_csum));
> skb->ip_summed = CHECKSUM_COMPLETE;
> }
>
> If this does not work, then maybe :
>
> diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c
> b/drivers/net/ethernet/freescale/enetc/enetc.c
> index 504e12554079e306e477b9619f272d6e96527377..d190faa9a8242f9f3f962dd30b9f4409a83ee697
> 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc.c
> @@ -987,7 +987,8 @@ static void enetc_get_offloads(struct enetc_bdr *rx_ring,
> u16 inet_csum = le16_to_cpu(rxbd->r.inet_csum);
>
> skb->csum = csum_unfold((__force __sum16)~htons(inet_csum));
> - skb->ip_summed = CHECKSUM_COMPLETE;
> + if (likely(skb->csum))
> + skb->ip_summed = CHECKSUM_COMPLETE;
> }
>
> if (le16_to_cpu(rxbd->r.flags) & ENETC_RXBD_FLAG_VLAN) {
I guess you aren't interested any longer in the result of these changes,
since the csum isn't zero in enetc?
next prev parent reply other threads:[~2021-12-02 21:07 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 20:24 [PATCH net-next 0/2] net: small csum optimizations Eric Dumazet
2021-11-24 20:24 ` [PATCH net-next 1/2] gro: optimize skb_gro_postpull_rcsum() Eric Dumazet
2021-11-24 20:24 ` [PATCH net-next 2/2] net: optimize skb_postpull_rcsum() Eric Dumazet
2021-11-25 9:41 ` David Laight
2021-11-25 13:32 ` Eric Dumazet
2021-11-25 14:29 ` David Laight
2021-12-02 13:10 ` Vladimir Oltean
2021-12-02 14:51 ` Eric Dumazet
2021-12-02 16:29 ` Vladimir Oltean
2021-12-02 19:32 ` Eric Dumazet
2021-12-02 20:37 ` Eric Dumazet
2021-12-02 21:07 ` Vladimir Oltean [this message]
2021-12-02 20:40 ` Vladimir Oltean
2021-12-02 20:58 ` Vladimir Oltean
2021-12-02 20:58 ` David Laight
2021-12-02 21:40 ` Vladimir Oltean
2021-12-03 14:51 ` David Laight
2021-12-03 14:57 ` David Laight
2021-12-03 16:14 ` Vladimir Oltean
2021-12-03 16:30 ` Eric Dumazet
2021-12-03 16:47 ` David Laight
2021-12-03 16:58 ` Eric Dumazet
2021-12-03 17:41 ` David Laight
2021-12-02 15:06 ` David Laight
2021-12-02 15:22 ` Eric Dumazet
2021-11-26 5:20 ` [PATCH net-next 0/2] net: small csum optimizations patchwork-bot+netdevbpf
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