Re: [PATCH v2 net] ixgbe: fix parsing of TC actions for HW offload

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

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On Thu, 2018-05-31 at 23:21 +0200, Ondřej Hlavatý wrote:
> The previous code was optimistic, accepting the offload of whole
> action
> chain when there was a single known action (drop/redirect). This
> results
> in offloading a rule which should not be offloaded, because its
> behavior
> cannot be reproduced in the hardware.
> 
> For example:
> 
> $ tc filter add dev eno1 parent ffff: protocol ip \
>     u32 ht 800: order 1 match tcp src 42 FFFF \
>     action mirred egress mirror dev enp1s16 pipe \
>     drop
> 
> The controller is unable to mirror the packet to a VF, but still
> offloads the rule by dropping the packet.
> 
> Change the approach of the function to a pessimistic one, rejecting
> the
> chain when an unknown action is found. This is better suited for
> future
> extensions.
> 
> Note that both recognized actions always return TC_ACT_SHOT,
> therefore
> it is safe to ignore actions behind them.
> 
> Signed-off-by: Ondřej Hlavatý <ohlavaty@redhat.com>

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Note- I am having our validation move to testing with GCC 8.1.1 or
later so that we can catch warnings like Dave found in the future.

Dave- Please go ahead and pick this up.

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