On 11/09/2020 17:01, Jakub Kicinski wrote:
> On Thu, 10 Sep 2020 21:33:11 +0100 Edward Cree wrote:
>> index 078c7ec2a70e..272eb5ecb7e7 100644
>> --- a/drivers/net/ethernet/sfc/ef100_tx.c
>> +++ b/drivers/net/ethernet/sfc/ef100_tx.c
>> @@ -38,7 +38,8 @@ void ef100_tx_init(struct efx_tx_queue *tx_queue)
>> tx_queue->channel->channel -
>> tx_queue->efx->tx_channel_offset);
>>
>> - if (efx_mcdi_tx_init(tx_queue, false))
>> + tx_queue->tso_version = 3;
>> + if (efx_mcdi_tx_init(tx_queue))
>> netdev_WARN(tx_queue->efx->net_dev,
>> "failed to initialise TXQ %d\n", tx_queue->queue);
>> }
>> --- a/drivers/net/ethernet/sfc/tx.c
>> +++ b/drivers/net/ethernet/sfc/tx.c
>> @@ -338,8 +338,18 @@ netdev_tx_t __efx_enqueue_skb(struct efx_tx_queue
>> *tx_queue, struct sk_buff *skb
>> * size limit.
>> */
>> if (segments) {
>> - EFX_WARN_ON_ONCE_PARANOID(!tx_queue->handle_tso);
>> - rc = tx_queue->handle_tso(tx_queue, skb, &data_mapped);
>> + switch (tx_queue->tso_version) {
>> + case 1:
>> + rc = efx_enqueue_skb_tso(tx_queue, skb, &data_mapped);
>> + break;
>> + case 2:
>> + rc = efx_ef10_tx_tso_desc(tx_queue, skb, &data_mapped);
>> + break;
>> + case 0: /* No TSO on this queue, SW fallback needed */
>> + default:
>> + rc = -EINVAL;
>> + break;
>> + }
> Should tso_version 3 be handled in this switch?
No, because this switch is in the EF10/Siena datapath and is neverrun for
EF100. Setting tx_queue->tso_version = 3 for EF100 is really just there
as documentation — EF100 has a completely different TX path, in
ef100_enqueue_skb(), which never looks at tx_queue->tso_version because
currently there's only one version of EF100 TSO descriptor. From a
functional perspective everything would still work if it were set to 0,
but that would be kinda misleading.
Should I explain this in the commit message, or in a comment (and if the
latter, where should it go?)
-ed
