Re: [PATCH 5/5] net/virtio: fix Tso when mbuf is shared

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 24 Nov 2016 09:56:38 +0100
Olivier Matz <olivier.matz@6wind.com> wrote:

> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 22d97a4..577c775 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -211,43 +211,73 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
>  
>  /* When doing TSO, the IP length is not included in the pseudo header
>   * checksum of the packet given to the PMD, but for virtio it is
> - * expected.
> + * expected. Fix the mbuf or a copy if the mbuf is shared.
>   */
> -static void
> -virtio_tso_fix_cksum(struct rte_mbuf *m)
> +static unsigned int
> +virtio_tso_fix_cksum(struct rte_mbuf *m, char *hdr, size_t hdr_sz)
>  {
> -	/* common case: header is not fragmented */
> -	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
> -			m->l4_len)) {
> -		struct ipv4_hdr *iph;
> -		struct ipv6_hdr *ip6h;
> -		struct tcp_hdr *th;
> -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> -		uint32_t tmp;
> -
> -		iph = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *, m->l2_len);
> -		th = RTE_PTR_ADD(iph, m->l3_len);
> -		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 ipv6_hdr *)iph;
> -			ip_paylen = ip6h->payload_len;
> +	struct ipv4_hdr *iph, iph_copy;
> +	struct ipv6_hdr *ip6h = NULL, ip6h_copy;
> +	struct tcp_hdr *th, th_copy;
> +	size_t hdrlen = m->l2_len + m->l3_len + m->l4_len;
> +	uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> +	uint32_t tmp;
> +	int shared = 0;

Minor nit, uses bool instead of int for shared?