From: Ferruh Yigit <ferruh.yigit@amd.com>
To: Chaoyong He <chaoyong.he@corigine.com>, dev@dpdk.org
Cc: oss-drivers@corigine.com, niklas.soderlund@corigine.com, stable@dpdk.org
Subject: Re: [PATCH] net/nfp: fix the Tx descriptor free logic of nfd3
Date: Thu, 18 May 2023 11:33:29 +0100 [thread overview]
Message-ID: <de0d9c6f-a434-257e-d62e-4b05500023fe@amd.com> (raw)
In-Reply-To: <20230512020712.616206-1-chaoyong.he@corigine.com>
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: stable@dpdk.org
>
> Signed-off-by: Chaoyong He <chaoyong.he@corigine.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund@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")'
next prev parent reply other threads:[~2023-05-18 10:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-12 2:07 Chaoyong He
2023-05-18 10:33 ` Ferruh Yigit [this message]
2023-05-18 10:49 ` Chaoyong He
2023-05-18 11:02 ` [PATCH v2] " Chaoyong He
2023-05-18 14:43 ` Ferruh Yigit
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