From: Stephen Hemminger <stephen@networkplumber.org>
To: John Guzik <john@shieldxnetworks.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] vmxnet3 driver - vlan offload is on end descriptor
Date: Thu, 7 Apr 2016 10:35:22 -0700 [thread overview]
Message-ID: <20160407103522.2d3d7953@xeon-e3> (raw)
In-Reply-To: <SN1PR20MB028564DE6A82A22983157757DC900@SN1PR20MB0285.namprd20.prod.outlook.com>
On Thu, 7 Apr 2016 17:11:19 +0000
John Guzik <john@shieldxnetworks.com> wrote:
> With the new jumbo frame patch a latent bug has appeared to have been uncovered: the VLAN offload is on the last rx descriptor, when rcd->eop is true, not the first rx descriptor, when rcd->sop is true and rcd->eop could be false.
> Most likely the reason this has not been seen before is that for non-jumbo frames rcd->eop has always been true when rcd->sop is true as well.
>
> The following patch should fix the problem:
>
> diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c b/drivers/net/vmxnet3/vmxnet3_rxtx.c
> index 4ac0456..3d4a5eb 100644
> --- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
> +++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
> @@ -587,12 +587,6 @@ vmxnet3_post_rx_bufs(vmxnet3_rx_queue_t *rxq, uint8_t ring_id)
> static void
> vmxnet3_rx_offload(const Vmxnet3_RxCompDesc *rcd, struct rte_mbuf *rxm)
> {
> - /* Check for hardware stripped VLAN tag */
> - if (rcd->ts) {
> - rxm->ol_flags |= PKT_RX_VLAN_PKT;
> - rxm->vlan_tci = rte_le_to_cpu_16((uint16_t)rcd->tci);
> - }
> -
> /* Check for RSS */
> if (rcd->rssType != VMXNET3_RCD_RSS_TYPE_NONE) {
> rxm->ol_flags |= PKT_RX_RSS_HASH;
> @@ -737,7 +731,15 @@ vmxnet3_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
> rxq->last_seg = rxm;
>
> if (rcd->eop) {
> - rx_pkts[nb_rx++] = rxq->start_seg;
> + struct rte_mbuf *start = rxq->start_seg;
> +
> + /* Check for hardware stripped VLAN tag */
> + if (rcd->ts) {
> + start->ol_flags |= PKT_RX_VLAN_PKT;
> + start->vlan_tci = rte_le_to_cpu_16((uint16_t)rcd->tci);
> + }
> +
> + rx_pkts[nb_rx++] = start;
> rxq->start_seg = NULL;
> }
>
>
Yes, your analysis and bug fix looks correct. The Linux driver checks for VLAN tag in the
last (eop) segment.
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
next prev parent reply other threads:[~2016-04-07 17:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 17:11 John Guzik
2016-04-07 17:34 ` Thomas Monjalon
2016-04-07 18:22 ` Yong Wang
2016-04-07 17:35 ` Stephen Hemminger [this message]
2016-04-12 23:08 ` [dpdk-dev] [PATCH] vmxnet3: VLAN tag on end packet, not first John Guzik
2016-05-10 15:04 ` Bruce Richardson
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