[PATCH 20.11] net/nfp: fix Tx descriptor free logic of NFD3

[Luca Boccassi]

On Thu, 15 Jun 2023 at 07:22, Chaoyong He <chaoyong.he at corigine.com> wrote:
>
> [ upstream commit 36d0f4238b2f79850695f49b191ddd4540ff88a6 ]
>
> 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")
>
> Signed-off-by: Chaoyong He <chaoyong.he at corigine.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund at corigine.com>
> ---
>  drivers/net/nfp/nfp_net.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)

Thanks, applied