linux/drivers/infiniband/ulp/ipoib
Eric Dumazet 0287587884 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>
2014-10-07 13:22:11 -04:00
..
Kconfig kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT 2011-01-20 17:02:05 -08:00
Makefile IB/ipoib: Add rtnl_link_ops support 2012-09-20 16:49:17 -04:00
ipoib.h ipoib: validate struct ipoib_cb size 2014-09-22 14:29:55 -04:00
ipoib_cm.c IB: Add a QP creation flag to use GFP_NOIO allocations 2014-06-02 14:58:11 -07:00
ipoib_ethtool.c net: get rid of SET_ETHTOOL_OPS 2014-05-13 17:43:20 -04:00
ipoib_fs.c IPoIB: Remove unnecessary test for NULL before debugfs_remove() 2014-08-12 21:59:54 -07:00
ipoib_ib.c IB/ipoib: Avoid multicast join attempts with invalid P_key 2014-08-10 19:53:56 -07:00
ipoib_main.c net: better IFF_XMIT_DST_RELEASE support 2014-10-07 13:22:11 -04:00
ipoib_multicast.c IPoIB: Remove unnecessary port query 2014-09-19 10:17:40 -07:00
ipoib_netlink.c infiniband: make sure the src net is infiniband when create new link 2014-01-03 20:38:56 -05:00
ipoib_verbs.c IB/core: Add flow steering support for IPoIB UD traffic 2014-01-14 14:06:50 -08:00
ipoib_vlan.c IPoIB: Fix deadlock between dev_change_flags() and __ipoib_dev_flush() 2013-11-08 14:42:49 -08:00