RE: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Boleslav,

The change seems good, but patchwork is complaining about lack of .mailmap change.

http://mails.dpdk.org/archives/test-report/2023-March/363061.html

Guess this is your first patch? So you need to add name and email in mailmap file.

Thanks,
Chenbo

> -----Original Message-----
> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Sent: Friday, March 3, 2023 11:14 PM
> To: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>; dev@dpdk.org
> Cc: stable@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>; Xia,
> Chenbo <chenbo.xia@intel.com>
> Subject: Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO
> checksum
> 
> Cc Maxime and Chenbo
> 
> On 3/3/23 14:19, Boleslav Stankevich wrote:
> > The length of TSO payload could not fit into 16 bits provided by the
> > IPv4 total length and IPv6 payload length fields. Thus, deduce it
> > from the length of the packet.
> >
> > Fixes: 696573046e9 ("net/virtio: support TSO")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> > Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> > ---
> >   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
> >   1 file changed, 16 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> > index 2d0afd3302..e48ff3cca7 100644
> > --- a/drivers/net/virtio/virtio_rxtx.c
> > +++ b/drivers/net/virtio/virtio_rxtx.c
> > @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
> >   	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
> >   			m->l4_len)) {
> >   		struct rte_ipv4_hdr *iph;
> > -		struct rte_ipv6_hdr *ip6h;
> >   		struct rte_tcp_hdr *th;
> > -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> > +		uint16_t prev_cksum, new_cksum;
> > +		uint32_t ip_paylen;
> >   		uint32_t tmp;
> >
> >   		iph = rte_pktmbuf_mtod_offset(m,
> >   					struct rte_ipv4_hdr *, m->l2_len);
> >   		th = RTE_PTR_ADD(iph, m->l3_len);
> > +
> > +		/*
> > +		 * Calculate IPv4 header checksum with current total length
> value
> > +		 * (whatever it is) to have correct checksum after update on
> edits
> > +		 * done by TSO.
> > +		 */
> >   		if ((iph->version_ihl >> 4) == 4) {
> >   			iph->hdr_checksum = 0;
> >   			iph->hdr_checksum = rte_ipv4_cksum(iph);
> > -			ip_len = iph->total_length;
> > -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
> > -				m->l3_len);
> > -		} else {
> > -			ip6h = (struct rte_ipv6_hdr *)iph;
> > -			ip_paylen = ip6h->payload_len;
> >   		}
> >
> > +		/*
> > +		 * Do not use IPv4 total length and IPv6 payload length fields
> to get
> > +		 * TSO payload length since it could not fit into 16 bits.
> > +		 */
> > +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m-
> >l2_len -
> > +					m->l3_len);
> > +
> >   		/* calculate the new phdr checksum not including ip_paylen */
> >   		prev_cksum = th->cksum;
> >   		tmp = prev_cksum;
> > -		tmp += ip_paylen;
> > +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
> >   		tmp = (tmp & 0xffff) + (tmp >> 16);
> >   		new_cksum = tmp;
> >