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")'
