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Subject: Re: [PATCH] net: ethernet: ravb: fix dma mapping failure handling
To: Nikita Yushchenko <nikita.yoush@cogentembedded.com>, "David S. Miller"
	<davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Paolo Abeni
	<pabeni@redhat.com>
CC: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>, Yoshihiro Shimoda
	<yoshihiro.shimoda.uh@renesas.com>, Wolfram Sang
	<wsa+renesas@sang-engineering.com>, =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?=
	<u.kleine-koenig@pengutronix.de>, <netdev@vger.kernel.org>,
	<linux-renesas-soc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20240112050639.405784-1-nikita.yoush@cogentembedded.com>
From: Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <6e5150c8-452a-f794-dbf4-18b64bcae206@omp.ru>
Date: Fri, 12 Jan 2024 23:15:33 +0300
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On 1/12/24 8:06 AM, Nikita Yushchenko wrote:

> dma_mapping_error() depends on getting full 64-bit dma_addr_t and does
> not work correctly if 32-bit value is passed instead.
> 
> Fix handling of dma_map_single() failures on Rx ring entries:
> - do not store return value of dma_map_signle() in 32-bit variable,

   This one is on the TX path, in ravb_start_xmit()... :-/

> - do not use dma_mapping_error() against 32-bit descriptor field when
>   checking if unmap is needed, check for zero size instead.

   This one is on the RX path indeed...
   I suggest that you split this patch to the RX/TX path patches, as it fixes different issues.

> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>

   You forgot to specify the Fixes tag (we'd need two of those,
one per patch)...

> ---
>  drivers/net/ethernet/renesas/ravb_main.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 8649b3e90edb..4d4b5d44c4e7 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -256,8 +256,7 @@ static void ravb_rx_ring_free_gbeth(struct net_device *ndev, int q)
>  	for (i = 0; i < priv->num_rx_ring[q]; i++) {
>  		struct ravb_rx_desc *desc = &priv->gbeth_rx_ring[i];
>  
> -		if (!dma_mapping_error(ndev->dev.parent,
> -				       le32_to_cpu(desc->dptr)))
> +		if (le16_to_cpu(desc->ds_cc) != 0)
>  			dma_unmap_single(ndev->dev.parent,
>  					 le32_to_cpu(desc->dptr),
>  					 GBETH_RX_BUFF_MAX,
> @@ -281,8 +280,7 @@ static void ravb_rx_ring_free_rcar(struct net_device *ndev, int q)
>  	for (i = 0; i < priv->num_rx_ring[q]; i++) {
>  		struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
>  
> -		if (!dma_mapping_error(ndev->dev.parent,
> -				       le32_to_cpu(desc->dptr)))
> +		if (le16_to_cpu(desc->ds_cc) != 0)
>  			dma_unmap_single(ndev->dev.parent,
>  					 le32_to_cpu(desc->dptr),
>  					 RX_BUF_SZ,

   For these hunks it will be:

Fixes: a47b70ea86bd ("ravb: unmap descriptors when freeing rings")

> @@ -1949,7 +1947,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>  	struct ravb_tstamp_skb *ts_skb;
>  	struct ravb_tx_desc *desc;
>  	unsigned long flags;
> -	u32 dma_addr;
> +	dma_addr_t dma_addr;
>  	void *buffer;
>  	u32 entry;
>  	u32 len;

   And for this hunk it will be:

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")

MBR, Sergey