Messages in this thread | | | From | Rafal Ozieblo <> | Subject | RE: [PATCH net-next v5] cadence: Add LSO support. | Date | Mon, 14 Nov 2016 09:32:34 +0000 |
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From: David Miller [mailto:davem@davemloft.net] Sent: 10 listopada 2016 18:01 To: Rafal Ozieblo Cc: nicolas.ferre@atmel.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v5]] cadence: Add LSO support.
From: Rafal Ozieblo <rafalo@cadence.com> Date: Wed, 9 Nov 2016 13:41:02 +0000
> First, please remove the spurious closing bracket in your Subject line in future submittions. > >> + if (is_udp) /* is_udp is only set when (is_lso) is checked */ >> + /* zero UDP checksum, not calculated by h/w for UFO */ >> + udp_hdr(skb)->check = 0; > > This is really not ok. > > If UFO is in use it should not silently disable UDP checksums. > > If you cannot support UFO with proper checksumming, then you cannot enable support for that feature.
According Cadence Gigabit Ethernet MAC documentation:
"Hardware will not calculate the UDP checksum or modify the UDP checksum field. Therefore software must set a value of zero in the checksum field in the UDP header (in the first payload buffer) to indicate to the receiver that the UDP datagram does not include a checksum."
It is hardware requirement.
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