Inspired by commit f09e2249c4f5c7c13261ec73f5a7807076af0c8e (macvtap: restore
vlan header on user read). This patch adds hardware vlan tx support for
tuntap. This is done by copying vlan header directly into userspace in
tun_put_user() instead of doing it through __vlan_put_tag() in
dev_hard_start_xmit(). This eliminates one unnecessary memove in
vlan_insert_tag() for 802.1ad and 802.1q traffic.
pktgen test shows about 20% improvement for 802.1q traffic:
Before:
662149pps 317Mb/sec (317831520bps) errors: 0
After:
801033pps 384Mb/sec (384495840bps) errors: 0
Cc: Basil Gor <basil.gor@xxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/net/tun.c | 39 +++++++++++++++++++++++++++++++++++----
1 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c[...]
index a72d141..66e265d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1328,11 +1330,39 @@ static ssize_t tun_put_user(struct tun_struct *tun,
total += tun->vnet_hdr_sz;
}
- len = min_t(int, skb->len, len);
+ if (!vlan_tx_tag_present(skb))
+ len = min_t(int, skb->len, len);
+ else {
+ int copy, ret;
+ struct {
+ __be16 h_vlan_proto;
+ __be16 h_vlan_TCI;
+ } veth;
+ veth.h_vlan_proto = skb->vlan_proto;[...]
+ veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));