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 <[email protected]> > Cc: Neil Horman <[email protected]> > Cc: [email protected] > Signed-off-by: Jason Wang <[email protected]> > Acked-by: Neil Horman <[email protected]>
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