Re: [PATCH net v3] ixgbe: fix double clean of tx descriptors with xdp

[Alexander Duyck]

On Thu, Aug 22, 2019 at 10:12 AM Ilya Maximets <i.maximets@xxxxxxxxxxx> wrote:
>
> Tx code doesn't clear the descriptors' status after cleaning.
> So, if the budget is larger than number of used elems in a ring, some
> descriptors will be accounted twice and xsk_umem_complete_tx will move
> prod_tail far beyond the prod_head breaking the completion queue ring.
>
> Fix that by limiting the number of descriptors to clean by the number
> of used descriptors in the tx ring.
>
> 'ixgbe_clean_xdp_tx_irq()' function refactored to look more like
> 'ixgbe_xsk_clean_tx_ring()' since we're allowed to directly use
> 'next_to_clean' and 'next_to_use' indexes.
>
> Fixes: 8221c5eba8c1 ("ixgbe: add AF_XDP zero-copy Tx support")
> Signed-off-by: Ilya Maximets <i.maximets@xxxxxxxxxxx>
> ---
>
> Version 3:
>   * Reverted some refactoring made for v2.
>   * Eliminated 'budget' for tx clean.
>   * prefetch returned.
>
> Version 2:
>   * 'ixgbe_clean_xdp_tx_irq()' refactored to look more like
>     'ixgbe_xsk_clean_tx_ring()'.
>
>  drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 29 ++++++++------------
>  1 file changed, 11 insertions(+), 18 deletions(-)

Thanks for addressing my concerns.

Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>