net: better IFF_XMIT_DST_RELEASE support
Testing xmit_more support with netperf and connected UDP sockets,
I found strange dst refcount false sharing.
Current handling of IFF_XMIT_DST_RELEASE is not optimal.
Dropping dst in validate_xmit_skb() is certainly too late in case
packet was queued by cpu X but dequeued by cpu Y
The logical point to take care of drop/force is in __dev_queue_xmit()
before even taking qdisc lock.
As Julian Anastasov pointed out, need for skb_dst() might come from some
packet schedulers or classifiers.
This patch adds new helper to cleanly express needs of various drivers
or qdiscs/classifiers.
Drivers that need skb_dst() in their ndo_start_xmit() should call
following helper in their setup instead of the prior :
dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
->
netif_keep_dst(dev);
Instead of using a single bit, we use two bits, one being
eventually rebuilt in bonding/team drivers.
The other one, is permanent and blocks IFF_XMIT_DST_RELEASE being
rebuilt in bonding/team. Eventually, we could add something
smarter later.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/appletalk/ipddp.c b/drivers/net/appletalk/ipddp.c
index 10d0dba..e90c6a7 100644
--- a/drivers/net/appletalk/ipddp.c
+++ b/drivers/net/appletalk/ipddp.c
@@ -74,7 +74,7 @@
if (!dev)
return ERR_PTR(-ENOMEM);
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
strcpy(dev->name, "ipddp%d");
if (version_printed++ == 0)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3ad5413..c9ac06c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1002,7 +1002,8 @@
static void bond_compute_features(struct bonding *bond)
{
- unsigned int flags, dst_release_flag = IFF_XMIT_DST_RELEASE;
+ unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
+ IFF_XMIT_DST_RELEASE_PERM;
netdev_features_t vlan_features = BOND_VLAN_FEATURES;
netdev_features_t enc_features = BOND_ENC_FEATURES;
struct net_device *bond_dev = bond->dev;
@@ -1038,8 +1039,10 @@
bond_dev->gso_max_segs = gso_max_segs;
netif_set_gso_max_size(bond_dev, gso_max_size);
- flags = bond_dev->priv_flags & ~IFF_XMIT_DST_RELEASE;
- bond_dev->priv_flags = flags | dst_release_flag;
+ bond_dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ if ((bond_dev->priv_flags & IFF_XMIT_DST_RELEASE_PERM) &&
+ dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM))
+ bond_dev->priv_flags |= IFF_XMIT_DST_RELEASE;
netdev_change_features(bond_dev);
}
diff --git a/drivers/net/eql.c b/drivers/net/eql.c
index 957e5c0..a10ad74 100644
--- a/drivers/net/eql.c
+++ b/drivers/net/eql.c
@@ -199,7 +199,7 @@
dev->type = ARPHRD_SLIP;
dev->tx_queue_len = 5; /* Hands them off fast */
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
}
static int eql_open(struct net_device *dev)
diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index d2d4a3d..34f846b 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -185,7 +185,8 @@
dev->flags |= IFF_NOARP;
dev->flags &= ~IFF_MULTICAST;
- dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
+ dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+ netif_keep_dst(dev);
eth_hw_addr_random(dev);
}
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 8f22625..c76283c 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -169,7 +169,7 @@
dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
dev->flags = IFF_LOOPBACK;
dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO;
dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
| NETIF_F_ALL_TSO
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index e8a453f..38b4fae 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1025,7 +1025,8 @@
{
ether_setup(dev);
- dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
+ dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+ netif_keep_dst(dev);
dev->priv_flags |= IFF_UNICAST_FLT;
dev->netdev_ops = &macvlan_netdev_ops;
dev->destructor = free_netdev;
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index fa0d717..80e6f34 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1103,7 +1103,7 @@
dev->type = ARPHRD_PPP;
dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
dev->features |= NETIF_F_NETNS_LOCAL;
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
}
/*
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index 2277c36..a94a9df 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -970,7 +970,8 @@
struct team_port *port;
u32 vlan_features = TEAM_VLAN_FEATURES & NETIF_F_ALL_FOR_ALL;
unsigned short max_hard_header_len = ETH_HLEN;
- unsigned int flags, dst_release_flag = IFF_XMIT_DST_RELEASE;
+ unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
+ IFF_XMIT_DST_RELEASE_PERM;
list_for_each_entry(port, &team->port_list, list) {
vlan_features = netdev_increment_features(vlan_features,
@@ -985,8 +986,9 @@
team->dev->vlan_features = vlan_features;
team->dev->hard_header_len = max_hard_header_len;
- flags = team->dev->priv_flags & ~IFF_XMIT_DST_RELEASE;
- team->dev->priv_flags = flags | dst_release_flag;
+ team->dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ if (dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM))
+ team->dev->priv_flags |= IFF_XMIT_DST_RELEASE;
netdev_change_features(team->dev);
}
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 2af795d..2a51e6e 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2193,7 +2193,7 @@
dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
dev->hw_features |= NETIF_F_GSO_SOFTWARE;
dev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
INIT_LIST_HEAD(&vxlan->next);
diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index e5c7e61..3ebed1c 100644
--- a/drivers/net/wan/hdlc_fr.c
+++ b/drivers/net/wan/hdlc_fr.c
@@ -1047,7 +1047,7 @@
dev->flags = IFF_POINTOPOINT;
dev->hard_header_len = 10;
dev->addr_len = 2;
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
}
static const struct net_device_ops pvc_ops = {