From: Edward Cree <ecree@solarflare.com>
To: David Laight <David.Laight@ACULAB.COM>,
David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-net-drivers@solarflare.com"
<linux-net-drivers@solarflare.com>,
"tom@herbertland.com" <tom@herbertland.com>,
"alexander.duyck@gmail.com" <alexander.duyck@gmail.com>
Subject: Re: [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4
Date: Mon, 11 Jan 2016 13:21:29 +0000 [thread overview]
Message-ID: <5693AC59.4080702@solarflare.com> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CCC1D7E@AcuExch.aculab.com>
On 11/01/16 10:09, David Laight wrote:
> From: Edward Cree
>> Sent: 08 January 2016 19:47
> ...
>> + if (skb->ip_summed == CHECKSUM_PARTIAL) {
>> + csum = csum_fold(lco_csum(skb));
>> + if (csum == 0)
>> + csum = CSUM_MANGLED_0;
>> + return csum;
>> + } else {
>> + return csum_fold(skb_checksum(skb, 0, skb->len, 0));
>> + }
> You see to be worried about csum_fold() returning 0 in one
> path, but not in the other.
> I'm guessing that 0 can only happen if all the bytes that have
> been checksummed are zero.
csum_fold complements, so if the sum comes to (say) 0x1fffe, it will return ~0xffff which is 0.
Next version of patch will mangle 0 for both branches.
-ed
next prev parent reply other threads:[~2016-01-11 13:21 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-08 19:44 [PATCH v3 net-next 0/8] Local Checksum Offload Edward Cree
2016-01-08 19:45 ` [PATCH net-next 1/8] net: local checksum offload for encapsulation Edward Cree
2016-01-28 7:04 ` Zang MingJie
2016-01-28 9:00 ` Alexander Duyck
2016-01-28 17:09 ` Tom Herbert
2016-01-08 19:45 ` [PATCH net-next 2/8] net: udp: always set up for CHECKSUM_PARTIAL offload Edward Cree
2016-01-08 19:45 ` [PATCH net-next 3/8] net: enable LCO for udp_tunnel_handle_offloads() users Edward Cree
2016-01-08 19:45 ` [PATCH net-next 4/8] net: vxlan: enable local checksum offload Edward Cree
2016-01-08 19:46 ` [PATCH net-next 5/8] fou: enable LCO in FOU and GUE Edward Cree
2016-01-08 19:47 ` [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4 Edward Cree
2016-01-11 10:09 ` David Laight
2016-01-11 13:21 ` Edward Cree [this message]
2016-01-11 18:39 ` Alexander Duyck
2016-01-11 19:02 ` Edward Cree
2016-01-20 19:11 ` Rustad, Mark D
2016-01-20 19:35 ` Alexander Duyck
2016-01-20 19:58 ` Tom Herbert
2016-01-20 21:13 ` Alexander Duyck
2016-01-20 23:34 ` Rustad, Mark D
2016-01-08 19:47 ` [PATCH net-next 7/8] net: ip_tunnel: remove 'csum_help' argument to iptunnel_handle_offloads Edward Cree
2016-01-09 0:35 ` Alexander Duyck
2016-01-09 0:44 ` Tom Herbert
2016-01-09 2:05 ` Alexander Duyck
2016-01-09 3:00 ` Tom Herbert
2016-01-09 7:59 ` Alexander Duyck
2016-01-11 13:24 ` Edward Cree
2016-01-11 16:39 ` Alexander Duyck
2016-01-11 17:31 ` Edward Cree
2016-01-11 18:15 ` Alexander Duyck
2016-01-11 19:03 ` Edward Cree
2016-01-11 21:00 ` Alexander Duyck
2016-01-08 19:47 ` [PATCH net-next 8/8] Documentation/networking: add checksum-offloads.txt to explain LCO Edward Cree
-- strict thread matches above, loose matches on Subject: below --
2016-02-05 20:39 [PATCH v4 net-next 0/8] Local Checksum Offload Edward Cree
2016-02-05 20:42 ` [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4 Edward Cree
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