linux/net
Jason Wang f663dd9aaf net: core: explicitly select a txq before doing l2 forwarding
Currently, the tx queue were selected implicitly in ndo_dfwd_start_xmit(). The
will cause several issues:

- NETIF_F_LLTX were removed for macvlan, so txq lock were done for macvlan
  instead of lower device which misses the necessary txq synchronization for
  lower device such as txq stopping or frozen required by dev watchdog or
  control path.
- dev_hard_start_xmit() was called with NULL txq which bypasses the net device
  watchdog.
- dev_hard_start_xmit() does not check txq everywhere which will lead a crash
  when tso is disabled for lower device.

Fix this by explicitly introducing a new param for .ndo_select_queue() for just
selecting queues in the case of l2 forwarding offload. netdev_pick_tx() was also
extended to accept this parameter and dev_queue_xmit_accel() was used to do l2
forwarding transmission.

With this fixes, NETIF_F_LLTX could be preserved for macvlan and there's no need
to check txq against NULL in dev_hard_start_xmit(). Also there's no need to keep
a dedicated ndo_dfwd_start_xmit() and we can just reuse the code of
dev_queue_xmit() to do the transmission.

In the future, it was also required for macvtap l2 forwarding support since it
provides a necessary synchronization method.

Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: e1000-devel@lists.sourceforge.net
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-10 13:23:08 -05:00
..
9p
802
8021q
appletalk
atm
ax25
batman-adv
bluetooth
bridge
caif
can
ceph
core net: core: explicitly select a txq before doing l2 forwarding 2014-01-10 13:23:08 -05:00
dcb
dccp
decnet
dns_resolver
dsa
ethernet
hsr
ieee802154
ipv4
ipv6
ipx
irda
iucv
key
l2tp
lapb
llc
mac80211 net: core: explicitly select a txq before doing l2 forwarding 2014-01-10 13:23:08 -05:00
mac802154
mpls
netfilter
netlabel
netlink
netrom
nfc
openvswitch
packet
phonet
rds
rfkill
rose
rxrpc
sched net: core: explicitly select a txq before doing l2 forwarding 2014-01-10 13:23:08 -05:00
sctp
sunrpc
tipc
unix
vmw_vsock
wimax
wireless
x25
xfrm
Kconfig
Makefile
compat.c
nonet.c
socket.c
sysctl_net.c