diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2013-07-25 10:20:23 +0930 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-07-27 20:06:10 -0700 |
| commit | e7428e95a06fb516fac1308bd0e176e27c0b9287 (patch) | |
| tree | 7ccd3f84a565b24ddf7efe5b10325cfd34ad98fc /include/uapi/linux/virtio_net.h | |
| parent | 10eccb46b521359fa344f63459087df722f0776d (diff) | |
| download | blackbird-op-linux-e7428e95a06fb516fac1308bd0e176e27c0b9287.tar.gz blackbird-op-linux-e7428e95a06fb516fac1308bd0e176e27c0b9287.zip | |
virtio-net: put virtio net header inline with data
For small packets we can simplify xmit processing
by linearizing buffers with the header:
most packets seem to have enough head room
we can use for this purpose.
Since existing hypervisors require that header
is the first s/g element, we need a feature bit
for this.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi/linux/virtio_net.h')
| -rw-r--r-- | include/uapi/linux/virtio_net.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index c520203fac2f..227d4ce84e79 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -70,7 +70,9 @@ struct virtio_net_config { __u16 max_virtqueue_pairs; } __attribute__((packed)); -/* This is the first element of the scatter-gather list. If you don't +/* This header comes first in the scatter-gather list. + * If VIRTIO_F_ANY_LAYOUT is not negotiated, it must + * be the first element of the scatter-gather list. If you don't * specify GSO or CSUM features, you can simply ignore the header. */ struct virtio_net_hdr { #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset |
