On 05/14/2018 04:07 PM, Willem de Bruijn wrote:
> From: Willem de Bruijn <will...@google.com>
>
> Paged allocation stores most payload in skb frags. This helps udp gso
> by avoiding copying from the gso skb to segment skb in skb_segment.
>
> But without scatter-gather, data must be linear, so do not use paged
> mode unless NETIF_F_SG.
>
> Fixes: 15e36f5b8e98 ("udp: paged allocation with gso")
> Reported-by: Sean Tranchetti <stran...@codeaurora.org>
> Signed-off-by: Willem de Bruijn <will...@google.com>
> ---
> net/ipv4/ip_output.c | 2 +-
> net/ipv6/ip6_output.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
> index b5e21eb198d8..b38731d8a44f 100644
> --- a/net/ipv4/ip_output.c
> +++ b/net/ipv4/ip_output.c
> @@ -884,7 +884,7 @@ static int __ip_append_data(struct sock *sk,
>
> exthdrlen = !skb ? rt->dst.header_len : 0;
> mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize;
> - paged = !!cork->gso_size;
> + paged = cork->gso_size && (rt->dst.dev->features & NETIF_F_SG);
>
> if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
> sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> index 7f4493080df6..35a940b9f208 100644
> --- a/net/ipv6/ip6_output.c
> +++ b/net/ipv6/ip6_output.c
> @@ -1262,7 +1262,7 @@ static int __ip6_append_data(struct sock *sk,
> dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
> }
>
> - paged = !!cork->gso_size;
> + paged = cork->gso_size && (rt->dst.dev->features & NETIF_F_SG);
> mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
> orig_mtu = mtu;
>
>
As I said, this wont help for stacked device
bonding might advertise NETIF_F_SG, but one slave might not.
