DPDK patches and discussions
 help / color / mirror / Atom feed
From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Somnath Kotur <somnath.kotur@broadcom.com>
Cc: dev <dev@dpdk.org>, Ferruh Yigit <ferruh.yigit@intel.com>,
	Olivier Matz <olivier.matz@6wind.com>,
	Hemant Agrawal <hemant.agrawal@nxp.com>,
	"Sachin Saxena" <sachin.saxena@nxp.com>
Subject: Re: [dpdk-dev] [RFC PATCH] mbuf: fix to update documentation of PKT_RX_QINQ_STRIPPED
Date: Mon, 16 Dec 2019 12:13:06 +0300
Message-ID: <53c0b3d2-5d61-6300-178e-b9500a93a7e3@solarflare.com> (raw)
In-Reply-To: <CAOBf=muFZLXDYoqDQdZP-SjC+mx2Okpju8539s+-fpHK-xcu=w@mail.gmail.com>

On 12/16/19 11:47 AM, Somnath Kotur wrote:
> On Mon, Dec 16, 2019 at 12:01 PM Andrew Rybchenko
> <arybchenko@solarflare.com> wrote:
>>
>> On 12/16/19 6:16 AM, Somnath Kotur wrote:
>>> Certain hardware may be able to strip and/or save only the outermost
>>> VLAN instead of both the VLANs in the mbuf in a QinQ scenario.
>>> To handle such cases, we could re-interpret setting of just PKT_RX_QINQ_STRIPPED
>>> to indicate that only the outermost VLAN has been stripped by the hardware and
>>> saved in mbuf->vlan_tci_outer.
>>> Only When both PKT_RX_QINQ_STRIPPED and PKT_RX_VLAN_STRIPPED are set, the 2 vlans
>>> have been stripped by the hardware and their tci are saved in mbuf->vlan_tci (inner)
>>> and mbuf->vlan_tci_outer (outer).
>>>
>>> Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
>>> Signed-off-by: JP Lee <jongpil.lee@broadcom.com>
>>> ---
>>>  lib/librte_mbuf/rte_mbuf_core.h | 15 +++++++++++----
>>>  1 file changed, 11 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/lib/librte_mbuf/rte_mbuf_core.h b/lib/librte_mbuf/rte_mbuf_core.h
>>> index 9a8557d..db1070b 100644
>>> --- a/lib/librte_mbuf/rte_mbuf_core.h
>>> +++ b/lib/librte_mbuf/rte_mbuf_core.h
>>> @@ -124,12 +124,19 @@
>>>  #define PKT_RX_FDIR_FLX      (1ULL << 14)
>>>
>>>  /**
>>> - * The 2 vlans have been stripped by the hardware and their tci are
>>> - * saved in mbuf->vlan_tci (inner) and mbuf->vlan_tci_outer (outer).
>>> + * The outer vlan has been stripped by the hardware and their tci are
>>> + * saved in mbuf->vlan_tci_outer (outer).
>>>   * This can only happen if vlan stripping is enabled in the RX
>>>   * configuration of the PMD.
>>> - * When PKT_RX_QINQ_STRIPPED is set, the flags (PKT_RX_VLAN |
>>> - * PKT_RX_VLAN_STRIPPED | PKT_RX_QINQ) must also be set.
>>> + * When PKT_RX_QINQ_STRIPPED is set, the flags (PKT_RX_VLAN |  PKT_RX_QINQ)
>>> + * must also be set.
>>> + * When both PKT_RX_QINQ_STRIPPED and PKT_RX_VLAN_STRIPPED are set, the 2 vlans
>>> + * have been stripped by the hardware and their tci are saved in
>>> + * mbuf->vlan_tci (inner) and mbuf->vlan_tci_outer (outer).
>>> + * This can only happen if vlan stripping is enabled in the RX configuration
>>> + * of the PMD.
>>> + * When PKT_RX_QINQ_STRIPPED and PKT_RX_VLAN_STRIPPED are set,
>>> + * (PKT_RX_VLAN | PKT_RX_QINQ) must also be set.
>>>   */
>>>  #define PKT_RX_QINQ_STRIPPED (1ULL << 15)
>>>
>>
>> I always thought that PKT_RX_VLAN_STRIPPED means *one* VLAN
>> stripped regardless if it is outer (if the packet is double
>> tagged) or inner (if only one VLAN tag was present).
>>
>> That's why PKT_RX_QINQ_STRIPPED description says that *two*
>> VLANs have been stripped.
>>
>> What is the problem with such approach?
> The problem is that RX_VLAN_STRIPPED implies that the stripped VLAN
> (outer or inner) is saved in mbuf->vlan_tci, correct?

Yes.

> There is no way to convey that it is in QinQ mode and yet only outer
> VLAN has been stripped and saved in mbuf->vlan_tci_outer ?

Ah, it looks like I understand now that the problem is in
PKT_RX_QINQ description which claims that TCI is saved in
mbuf->vlan_tci_outer and PKT_RX_QINQ_STRIPPED means that
both VLAN tags are stripped regardless (PKT_RX_VLAN_STRIPPED).
Moreover PKT_RX_QINQ_STRIPPED requires PKT_RX_VLAN_STRIPPED.

It means that PKT_RX_QINQ_STRIPPED, PKT_RX_QINQ, PKT_RX_VLAN
and PKT_RX_VLAN_STRIPPED must be clarified.

I'm not sure, but it looks like it could affect net/dpaa2,
so I'm including driver maintainers in CC.

  reply	other threads:[~2019-12-16  9:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  3:16 Somnath Kotur
2019-12-16  6:31 ` Andrew Rybchenko
2019-12-16  8:47   ` Somnath Kotur
2019-12-16  9:13     ` Andrew Rybchenko [this message]
2019-12-24  3:16       ` Somnath Kotur
2019-12-24  9:53         ` Andrew Rybchenko
2019-12-27 14:50           ` Olivier Matz
2019-12-31  2:13             ` Somnath Kotur
2020-01-02 12:57             ` Andrew Rybchenko
2019-12-31  2:15           ` Somnath Kotur
2020-01-02 13:04             ` Andrew Rybchenko
2020-01-06  8:36               ` Somnath Kotur

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=53c0b3d2-5d61-6300-178e-b9500a93a7e3@solarflare.com \
    --to=arybchenko@solarflare.com \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@intel.com \
    --cc=hemant.agrawal@nxp.com \
    --cc=olivier.matz@6wind.com \
    --cc=sachin.saxena@nxp.com \
    --cc=somnath.kotur@broadcom.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror http://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ http://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git