On 23/05/18 10:41, Martin Habets wrote:
> efx_enqueue_skb() can push new buffers for the xmit_more functionality.
> We must stops the TX queue before this or else the TX queue does not get
> restarted and we get a netdev watchdog.
>
> In the error handling we may now need to unwind more than 1 packet, and
> we may need to push the new buffers onto the partner queue.
>
> Fixes: e9117e5099ea ("sfc: Firmware-Assisted TSO version 2")
> Reported-by: Jarod Wilson <ja...@redhat.com>
> Signed-off-by: Martin Habets <mhab...@solarflare.com>
> ---
>
> Dave, could you please also queue up this patch for stable?
>
> drivers/net/ethernet/sfc/tx.c | 31 +++++++++++++++++++++++--------
> 1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
> index cece961f2e82..17e0697f42d5 100644
> --- a/drivers/net/ethernet/sfc/tx.c
> +++ b/drivers/net/ethernet/sfc/tx.c
> @@ -435,17 +435,18 @@ static int efx_tx_map_data(struct efx_tx_queue
> *tx_queue, struct sk_buff *skb,
> } while (1);
> }
>
> -/* Remove buffers put into a tx_queue. None of the buffers must have
> - * an skb attached.
> +/* Remove buffers put into a tx_queue for the current packet.
> + * None of the buffers must have an skb attached.
> */
> -static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
> +static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue,
> + unsigned int insert_count)
> {
> struct efx_tx_buffer *buffer;
> unsigned int bytes_compl = 0;
> unsigned int pkts_compl = 0;
>
> /* Work backwards until we hit the original insert pointer value */
> - while (tx_queue->insert_count != tx_queue->write_count) {
> + while (tx_queue->insert_count != insert_count) {
> --tx_queue->insert_count;
> buffer = __efx_tx_queue_get_insert_buffer(tx_queue);
> efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
> @@ -504,6 +505,8 @@ static int efx_tx_tso_fallback(struct efx_tx_queue
> *tx_queue,
> */
> netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff
> *skb)
> {
> + unsigned int old_insert_count = tx_queue->insert_count;
> + bool xmit_more = skb->xmit_more;
> bool data_mapped = false;
> unsigned int segments;
> unsigned int skb_len;
> @@ -553,8 +556,10 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue
> *tx_queue, struct sk_buff *skb)
> /* Update BQL */
> netdev_tx_sent_queue(tx_queue->core_txq, skb_len);
>
> + efx_tx_maybe_stop_queue(tx_queue);
> +
> /* Pass off to hardware */
> - if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq)) {
> + if (!xmit_more || netif_xmit_stopped(tx_queue->core_txq)) {
> struct efx_tx_queue *txq2 = efx_tx_queue_partner(tx_queue);
>
> /* There could be packets left on the partner queue if those
> @@ -577,14 +582,24 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue
> *tx_queue, struct sk_buff *skb)
> tx_queue->tx_packets++;
> }
>
> - efx_tx_maybe_stop_queue(tx_queue);
> -
> return NETDEV_TX_OK;
>
>
> err:
> - efx_enqueue_unwind(tx_queue);
> + efx_enqueue_unwind(tx_queue, old_insert_count);
> dev_kfree_skb_any(skb);
> +
> + /* If we're not expecting another transmit and we had something to push
> + * on this queue or a partner queue then we need to push here to get the
> + * previous packets out.
> + */
> + if (!xmit_more) {
> + struct efx_tx_queue *txq2 = efx_tx_queue_partner(tx_queue);
> +
> + if (txq2->xmit_more_available)
> + efx_nic_push_buffers(txq2);
> + }
This only pushes the partner queue, it needs to also push this queue if
tx_queue->xmit_more_available (as your comment just above mentions).
Apart from this, LGTM.
-Ed
> +
> return NETDEV_TX_OK;
> }
>
>
