virtio-net: restrict build_skb() use to some arches

build_skb() is supposed to be followed by
skb_reserve(skb, NET_IP_ALIGN), so that IP headers are word-aligned.
(Best practice is to reserve NET_IP_ALIGN+NET_SKB_PAD, but the NET_SKB_PAD
part is only a performance optimization if tunnel encaps are added.)

Unfortunately virtio_net has not provisioned this reserve.
We can only use build_skb() for arches where NET_IP_ALIGN == 0

We might refine this later, with enough testing.

Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Cc: Xuan Zhuo <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions