Re: [PATCH net-next 09/11] net: enetc: optimize the allocation of tx_bdr

[Frank Li]

On Wed, Oct 09, 2024 at 05:51:14PM +0800, Wei Fang wrote:
> From: Clark Wang <xiaoning.wang@xxxxxxx>
>
> There is a situation where num_tx_rings cannot be divided by
> bdr_int_num. For example, num_tx_rings is 8 and bdr_int_num
> is 3. According to the previous logic, this results in two
> tx_bdr corresponding memories not being allocated, so when
> sending packets to tx BD ring 6 or 7, wild pointers will be
> accessed. Of course, this issue does not exist for LS1028A,
> because its num_tx_rings is 8, and bdr_int_num is either 1
> or 2. So there is no situation where it cannot be divided.
> However, there is a risk for the upcoming i.MX95, so the
> allocation of tx_bdr is optimized to ensure that each tx_bdr
> can be allocated to the corresponding memory.
>
> Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
> Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
> Reviewed-by: Claudiu Manoil <claudiu.manoil@xxxxxxx>
> ---
>  drivers/net/ethernet/freescale/enetc/enetc.c | 121 ++++++++++---------
>  1 file changed, 62 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
> index 032d8eadd003..b84c88a76762 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc.c
> @@ -2965,13 +2965,70 @@ int enetc_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)
>  }
>  EXPORT_SYMBOL_GPL(enetc_ioctl);
>
> +static int enetc_bdr_init(struct enetc_ndev_priv *priv, int i, int v_tx_rings)
> +{
> +	struct enetc_int_vector *v __free(kfree);
> +	struct enetc_bdr *bdr;
> +	int j, err;
> +
> +	v = kzalloc(struct_size(v, tx_ring, v_tx_rings), GFP_KERNEL);
> +	if (!v)
> +		return -ENOMEM;
> +
> +	bdr = &v->rx_ring;
> +	bdr->index = i;
> +	bdr->ndev = priv->ndev;
> +	bdr->dev = priv->dev;
> +	bdr->bd_count = priv->rx_bd_count;
> +	bdr->buffer_offset = ENETC_RXB_PAD;
> +	priv->rx_ring[i] = bdr;
> +
> +	err = xdp_rxq_info_reg(&bdr->xdp.rxq, priv->ndev, i, 0);
> +	if (err)
> +		return err;
> +
> +	err = xdp_rxq_info_reg_mem_model(&bdr->xdp.rxq,
> +					 MEM_TYPE_PAGE_SHARED, NULL);
> +	if (err) {
> +		xdp_rxq_info_unreg(&bdr->xdp.rxq);
> +		return err;
> +	}
> +
> +	/* init defaults for adaptive IC */
> +	if (priv->ic_mode & ENETC_IC_RX_ADAPTIVE) {
> +		v->rx_ictt = 0x1;
> +		v->rx_dim_en = true;
> +	}
> +	INIT_WORK(&v->rx_dim.work, enetc_rx_dim_work);
> +	netif_napi_add(priv->ndev, &v->napi, enetc_poll);
> +	v->count_tx_rings = v_tx_rings;
> +
> +	for (j = 0; j < v_tx_rings; j++) {
> +		int idx;
> +
> +		/* default tx ring mapping policy */
> +		idx = priv->bdr_int_num * j + i;
> +		__set_bit(idx, &v->tx_rings_map);
> +		bdr = &v->tx_ring[j];
> +		bdr->index = idx;
> +		bdr->ndev = priv->ndev;
> +		bdr->dev = priv->dev;
> +		bdr->bd_count = priv->tx_bd_count;
> +		priv->tx_ring[idx] = bdr;
> +	}
> +
> +	priv->int_vector[i] = no_free_ptr(v);
> +
> +	return 0;
> +}
> +
>  int enetc_alloc_msix(struct enetc_ndev_priv *priv)
>  {
>  	struct pci_dev *pdev = priv->si->pdev;
> +	int v_tx_rings, v_remainder;
>  	int num_stack_tx_queues;
>  	int first_xdp_tx_ring;
>  	int i, n, err, nvec;
> -	int v_tx_rings;
>
>  	nvec = ENETC_BDR_INT_BASE_IDX + priv->bdr_int_num;
>  	/* allocate MSIX for both messaging and Rx/Tx interrupts */
> @@ -2985,65 +3042,11 @@ int enetc_alloc_msix(struct enetc_ndev_priv *priv)
>
>  	/* # of tx rings per int vector */
>  	v_tx_rings = priv->num_tx_rings / priv->bdr_int_num;
> +	v_remainder = priv->num_tx_rings % priv->bdr_int_num;
>
> -	for (i = 0; i < priv->bdr_int_num; i++) {
> -		struct enetc_int_vector *v;
> -		struct enetc_bdr *bdr;
> -		int j;
> -
> -		v = kzalloc(struct_size(v, tx_ring, v_tx_rings), GFP_KERNEL);
> -		if (!v) {
> -			err = -ENOMEM;
> -			goto fail;
> -		}
> -
> -		priv->int_vector[i] = v;
> -
> -		bdr = &v->rx_ring;
> -		bdr->index = i;
> -		bdr->ndev = priv->ndev;
> -		bdr->dev = priv->dev;
> -		bdr->bd_count = priv->rx_bd_count;
> -		bdr->buffer_offset = ENETC_RXB_PAD;
> -		priv->rx_ring[i] = bdr;
> -
> -		err = xdp_rxq_info_reg(&bdr->xdp.rxq, priv->ndev, i, 0);
> -		if (err) {
> -			kfree(v);
> -			goto fail;
> -		}
> -
> -		err = xdp_rxq_info_reg_mem_model(&bdr->xdp.rxq,
> -						 MEM_TYPE_PAGE_SHARED, NULL);
> -		if (err) {
> -			xdp_rxq_info_unreg(&bdr->xdp.rxq);
> -			kfree(v);
> -			goto fail;
> -		}
> -
> -		/* init defaults for adaptive IC */
> -		if (priv->ic_mode & ENETC_IC_RX_ADAPTIVE) {
> -			v->rx_ictt = 0x1;
> -			v->rx_dim_en = true;
> -		}
> -		INIT_WORK(&v->rx_dim.work, enetc_rx_dim_work);
> -		netif_napi_add(priv->ndev, &v->napi, enetc_poll);
> -		v->count_tx_rings = v_tx_rings;
> -
> -		for (j = 0; j < v_tx_rings; j++) {
> -			int idx;
> -
> -			/* default tx ring mapping policy */
> -			idx = priv->bdr_int_num * j + i;
> -			__set_bit(idx, &v->tx_rings_map);
> -			bdr = &v->tx_ring[j];
> -			bdr->index = idx;
> -			bdr->ndev = priv->ndev;
> -			bdr->dev = priv->dev;
> -			bdr->bd_count = priv->tx_bd_count;
> -			priv->tx_ring[idx] = bdr;
> -		}
> -	}
> +	for (i = 0; i < priv->bdr_int_num; i++)
> +		enetc_bdr_init(priv, i,
> +			       i < v_remainder ? v_tx_rings + 1 : v_tx_rings);

suggest you create two patches, one just move to help function to
enetc_bdr_init(), the another is for real fixes.

>
>  	num_stack_tx_queues = enetc_num_stack_tx_queues(priv);
>
> --
> 2.34.1
>