Re: [PATCH net-next 2/2] net: optimize skb_postpull_rcsum()
flat view
From: Vladimir Oltean <olteanv@gmail.com>
Date: 2021-12-02 21:07:14
On Thu, Dec 02, 2021 at 12:37:35PM -0800, Eric Dumazet wrote:
On Thu, Dec 2, 2021 at 11:32 AM Eric Dumazet [off-list ref] wrote:quoted
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.
quoted hunk ↗ jump to hunk
Perhapsdiff --git a/drivers/net/ethernet/freescale/enetc/enetc.cb/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.cb/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?