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tuntap: hardware vlan tx support 

Inspired by commit f09e2249c4 (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 memmove() 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@gmail.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2013-07-25 13:00:33 +08:00 committed by David S. Miller
parent 024ec3deac
commit 6680ec68ef
1 changed files with 36 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
drivers/net/tun.c
View File

@ -60,6 +60,7 @@
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/if_vlan.h>
#include <linux/crc32.h>
#include <linux/nsproxy.h>
#include <linux/virtio_net.h>
@ -1265,6 +1266,7 @@ static ssize_t tun_put_user(struct tun_struct *tun,
{
struct tun_pi pi = { 0, skb->protocol };
ssize_t total = 0;
int vlan_offset = 0;
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
@ -1328,11 +1330,40 @@ 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;
skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
total += skb->len;
veth.h_vlan_proto = skb->vlan_proto;
veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
len = min_t(int, skb->len + VLAN_HLEN, len);
copy = min_t(int, vlan_offset, len);
ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy);
len -= copy;
total += copy;
if (ret || !len)
goto done;
copy = min_t(int, sizeof(veth), len);
ret = memcpy_toiovecend(iv, (void *)&veth, total, copy);
len -= copy;
total += copy;
if (ret || !len)
goto done;
}
skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len);
total += len;
done:
tun->dev->stats.tx_packets++;
tun->dev->stats.tx_bytes += len;
@ -1691,7 +1722,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
tun_flow_init(tun);
dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
TUN_USER_FEATURES;
TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_STAG_TX;
dev->features = dev->hw_features;
dev->vlan_features = dev->features;