From: Jakub Kicinski <kuba@kernel•org>
To: Felix Fietkau <nbd@nbd•name>
Cc: netdev@vger•kernel.org
Subject: Re: [PATCH] net: dsa: tag_mtk: add padding for tx packets
Date: Mon, 9 May 2022 17:27:09 -0700 [thread overview]
Message-ID: <20220509172709.52c8fc8e@kernel.org> (raw)
In-Reply-To: <20220506194344.83702-1-nbd@nbd.name>
On Fri, 6 May 2022 21:43:44 +0200 Felix Fietkau wrote:
> From: Felix Fietkau <nbd@nbd•name>
> To: netdev@vger•kernel.org
Please repost and CC DSA maintainers.
> Subject: [PATCH] net: dsa: tag_mtk: add padding for tx packets
[PATCH net]
> Padding for transmitted packets needs to account for the special tag.
> With not enough padding, garbage bytes are inserted by the switch at the
> end of small packets.
>
> Fixes: 5cd8985a1909 ("net-next: dsa: add Mediatek tag RX/TX handler")
And CC anyone with tags on this commit.
> Signed-off-by: Felix Fietkau <nbd@nbd•name>
> ---
> net/dsa/tag_mtk.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
> index 415d8ece242a..1d1f9dbd9e93 100644
> --- a/net/dsa/tag_mtk.c
> +++ b/net/dsa/tag_mtk.c
> @@ -25,6 +25,14 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
> u8 xmit_tpid;
> u8 *mtk_tag;
>
> + /* The Ethernet switch we are interfaced with needs packets to be at
> + * least 64 bytes (including FCS) otherwise their padding might be
> + * corrupted. With tags enabled, we need to make sure that packets are
> + * at least 68 bytes (including FCS and tag).
> + */
> + if (__skb_put_padto(skb, ETH_ZLEN + MTK_HDR_LEN, false))
> + return NULL;
That doesn't happen for VLANs? Only the mtk tag is special?
prev parent reply other threads:[~2022-05-10 0:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-06 19:43 [PATCH] net: dsa: tag_mtk: add padding for tx packets Felix Fietkau
2022-05-10 0:27 ` Jakub Kicinski [this message]
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