Messages in this thread | | | Date | Fri, 10 Jan 2014 09:30:38 -0500 | From | Neil Horman <> | Subject | Re: [PATCH net V3 2/2] net: core: explicitly select a txq before doing l2 forwarding |
| |
On Fri, Jan 10, 2014 at 04:18:26PM +0800, Jason Wang wrote: > 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>
| |