Jeff,
Den fre 7 sep. 2018 kl 10:29 skrev Björn Töpel <bjorn.to...@gmail.com>:
>
> From: Björn Töpel <bjorn.to...@intel.com>
>
> When the zero-copy enabled XDP Tx ring is torn down, due to
> configuration changes, outstandning frames on the hardware descriptor
> ring are queued on the completion ring.
>
> The completion ring has a back-pressure mechanism that will guarantee
> that there is sufficient space on the ring.
>
> Signed-off-by: Björn Töpel <bjorn.to...@intel.com>
> ---
> drivers/net/ethernet/intel/i40e/i40e_txrx.c | 17 +++++++----
> .../ethernet/intel/i40e/i40e_txrx_common.h | 2 ++
> drivers/net/ethernet/intel/i40e/i40e_xsk.c | 30 +++++++++++++++++++
> 3 files changed, 43 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> index 37bd4e50ccde..7f85d4ba8b54 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> @@ -636,13 +636,18 @@ void i40e_clean_tx_ring(struct i40e_ring *tx_ring)
> unsigned long bi_size;
> u16 i;
>
> - /* ring already cleared, nothing to do */
> - if (!tx_ring->tx_bi)
> - return;
> + if (ring_is_xdp(tx_ring) && tx_ring->xsk_umem) {
> + i40e_xsk_clean_tx_ring(tx_ring);
> + } else {
> + /* ring already cleared, nothing to do */
> + if (!tx_ring->tx_bi)
> + return;
>
> - /* Free all the Tx ring sk_buffs */
> - for (i = 0; i < tx_ring->count; i++)
> - i40e_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
> + /* Free all the Tx ring sk_buffs */
> + for (i = 0; i < tx_ring->count; i++)
> + i40e_unmap_and_free_tx_resource(tx_ring,
> + &tx_ring->tx_bi[i]);
> + }
>
> bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count;
> memset(tx_ring->tx_bi, 0, bi_size);
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
> b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
> index b5afd479a9c5..29c68b29d36f 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
> @@ -87,4 +87,6 @@ static inline void i40e_arm_wb(struct i40e_ring *tx_ring,
> }
> }
>
> +void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring);
> +
> #endif /* I40E_TXRX_COMMON_ */
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> index 2ebfc78bbd09..99116277c4d2 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> @@ -830,3 +830,33 @@ int i40e_xsk_async_xmit(struct net_device *dev, u32
> queue_id)
>
> return 0;
> }
> +
> +/**
> + * i40e_xsk_clean_xdp_ring - Clean the XDP Tx ring on shutdown
> + * @xdp_ring: XDP Tx ring
> + **/
> +void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring)
> +{
> + u16 ntc = tx_ring->next_to_clean, ntu = tx_ring->next_to_use;
> + struct xdp_umem *umem = tx_ring->xsk_umem;
> + struct i40e_tx_buffer *tx_bi;
> + u32 xsk_frames = 0;
> +
> + while (ntc != ntu) {
> + tx_bi = &tx_ring->tx_bi[ntc];
> +
> + if (tx_bi->xdpf)
> + i40e_clean_xdp_tx_buffer(tx_ring, tx_bi);
> + else
> + xsk_frames++;
> +
> + tx_bi->xdpf = NULL;
> +
> + ntc++;
> + if (ntc > tx_ring->count)
This is an off-by-one error, and should be:
if (ntc == tx_ring->count)
Can you fix it up, or should I respin the patch?
Thanks!
Björn
> + ntc = 0;
> + }
> +
> + if (xsk_frames)
> + xsk_umem_complete_tx(umem, xsk_frames);
> +}
> --
> 2.17.1
>
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