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SubjectRe: [PATCH net-next 1/2] net: mvneta: add xmit_more support
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On Tue, 2016-09-13 at 07:33 -0700, Eric Dumazet wrote:

> Hi Marcin
>
> Well, given the above comment, and fact that MVNETA_MAX_TXD == 532, it
> looks like you might add a bug if more than 256 skb are given to your
> ndo_start_xmit() with skb->xmit_more = 1
>
> I therefore suggest you make sure it does not happen.
>
> txq->pending += frags;
> if (!skb->xmit_more ||
> txq->pending > 256 - MVNETA_MAX_SKB_DESCS ||
> netif_xmit_stopped(nq))
> mvneta_txq_pend_desc_add(pp, txq)
>

Another solution would be to test the potential overflow in mvneta_tx()
and force a mvneta_txq_pend_desc_add(pp, txq) _before_ adding the desc
of the "about to be cooked" TSO packet.

(This is because MVNETA_MAX_SKB_DESCS is 217, so 255-217 leaves few room
for xmit_more to show its power)




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