Re: [RFC net-next v3 2/2] bnxt: Use generic HBH removal helper in tx path

From: Coco Li
Date: Thu Dec 01 2022 - 21:03:25 EST


On Tue, Nov 29, 2022 at 12:42 PM Michael Chan <michael.chan@xxxxxxxxxxxx> wrote:
>
> On Tue, Nov 29, 2022 at 12:07 PM Coco Li <lixiaoyan@xxxxxxxxxx> wrote:
> > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > index 0fe164b42c5d..f144a5ef2e04 100644
> > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > @@ -389,6 +389,9 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
> > return NETDEV_TX_BUSY;
> > }
> >
> > + if (unlikely(ipv6_hopopt_jumbo_remove(skb)))
> > + goto tx_free;
> > +
> > length = skb->len;
> > len = skb_headlen(skb);
> > last_frag = skb_shinfo(skb)->nr_frags;
> > @@ -11342,9 +11345,15 @@ static bool bnxt_exthdr_check(struct bnxt *bp, struct sk_buff *skb, int nw_off,
> >
> > if (hdrlen > 64)
> > return false;
> > +
> > + /* The ext header may be a hop-by-hop header inserted for
> > + * big TCP purposes. This will be removed before sending
> > + * from NIC, so do not count it.
> > + */
> > + if (!(*nexthdr == NEXTHDR_HOP && ipv6_has_hopopt_jumbo(skb)))
>
> To be more efficient, why not just check the header's tlv_type here
> instead of calling ipv6_has_hopopt_jumbo()?
>

It may be possible that the next header is Hop_by_hop but the packet
is not tcp, meaning that it would not be removed and we'd still want
to count this header towards the limit.
ipv6_has_hopopt_jumbo checks for the big tcp case (gso, skb len
reaches a certain size) particularly.

> > + hdr_count++;
> > nexthdr = &hp->nexthdr;
> > start += hdrlen;
> > - hdr_count++;
> > }
> > if (nextp) {
> > /* Caller will check inner protocol */
> > @@ -13657,6 +13666,8 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> > dev->features &= ~NETIF_F_LRO;
> > dev->priv_flags |= IFF_UNICAST_FLT;
> >
> > + netif_set_tso_max_size(dev, GSO_MAX_SIZE);
> > +
> > #ifdef CONFIG_BNXT_SRIOV
> > init_waitqueue_head(&bp->sriov_cfg_wait);
> > #endif
> > --
> > 2.38.1.584.g0f3c55d4c2-goog
> >