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authorEric Dumazet <edumazet@google.com>2014-10-05 18:38:35 -0700
committerDavid S. Miller <davem@davemloft.net>2014-10-07 13:22:11 -0400
commit0287587884b15041203b3a362d485e1ab1f24445 (patch)
tree675ae57663c1ba3ee8768e65e7fb0e6d0259e04c /drivers/net/team/team.c
parentfe971b95c22578456ff7198537827841c726d3f7 (diff)
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>
Diffstat (limited to 'drivers/net/team/team.c')
-rw-r--r--drivers/net/team/team.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index 2277c3679a51..a94a9df3e6bd 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -970,7 +970,8 @@ static void __team_compute_features(struct team *team)
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 @@ static void __team_compute_features(struct team *team)
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);
}