> On 5/12/2023 3:07 AM, Chaoyong He wrote:
> > In the tx descriptor free logic of nfd3, the former logic might force
> > cast a negative number into a very big unsigned number, and which will
> > cause potential problem in the xmit loop.
> >
> > The xmit loop will continue in the place where it should break, and
> > will overwrite the Tx descriptor which is not free to use by the PMD.
> >
> > Fixes: 74a640dac864 ("net/nfp: avoid modulo operations for handling
> > ring wrapping")
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Chaoyong He <chaoyong...@corigine.com>
> > Reviewed-by: Niklas Söderlund <niklas.soderl...@corigine.com>
> > ---
> > drivers/net/nfp/nfp_rxtx.h | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/nfp/nfp_rxtx.h b/drivers/net/nfp/nfp_rxtx.h
> > index 5e651518ed..e642bc970a 100644
> > --- a/drivers/net/nfp/nfp_rxtx.h
> > +++ b/drivers/net/nfp/nfp_rxtx.h
> > @@ -401,10 +401,14 @@ nfp_net_mbuf_alloc_failed(struct nfp_net_rxq
> > *rxq) static inline uint32_t nfp_net_nfd3_free_tx_desc(struct
> > nfp_net_txq *txq) {
> > + uint32_t free_desc;
> > +
> > if (txq->wr_p >= txq->rd_p)
> > - return txq->tx_count - (txq->wr_p - txq->rd_p) - 8;
> > + free_desc = txq->tx_count - (txq->wr_p - txq->rd_p);
> > else
> > - return txq->rd_p - txq->wr_p - 8;
> > + free_desc = txq->rd_p - txq->wr_p;
> > +
> > + return (free_desc > 8) ? (free_desc - 8) : 0;
> > }
> >
> > /*
>
>
> Can you please rebase this patch on top of latest next-net?
>
> 'nfp_net_nfd3_free_tx_desc()' moved to 'drivers/net/nfp/nfd3/nfp_nfd3.h'
> in commit '2344d6272fe9 ("net/nfp: move NFD3 logic to own source file")'
Okay, I'll send out a v2 patch soon.
