Re: [PATCH net-next v14 1/7] r8169: prepare for multi irqs and napi

[netdev-bot+sashiko@kernel.org]

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issue(s) in other patches of this series. This mail is only an FYI, in case
you want to address the nit picks below when you respin.

Low priority / nit picks for your consideration:

- [Low] Commit message claims "there is no functional change", but the
  patch introduces two user-visible changes in…

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r8169: prepare for multi irqs and napi

This converts the single struct napi_struct in struct rtl8169_private into a
dynamically allocated array sized by the number of IRQ vectors, and moves
IRQ request/free into helpers that iterate over that array.  irq_nvecs and
num_rx_rings stay at 1, so this is described as a preparation step for RSS.

>     Currently, irq_nvecs and num_rx_rings are still hard-coded
>     to 1, so there is no functional change.

[Severity: Low]
Is the "no functional change" statement accurate?  There look to be two
observable changes for the currently supported single-vector case.

The first is the probe banner in rtl_init_one(), which gains a field that
always reads "(1 total)" while irq_nvecs is hard-coded to 1.

The second is the new netif_napi_set_irq() call in r8169_init_napi().
netif_napi_add_weight_locked() leaves napi->irq at -1, and
netdev_nl_napi_fill_one() only emits the attribute when it is non-negative:

net/core/netdev-genl.c:netdev_nl_napi_fill_one() {
	...
	if (napi->irq >= 0 && nla_put_u32(rsp, NETDEV_A_NAPI_IRQ, napi->irq))
		goto nla_put_failure;
	...
}

So NETDEV_A_NAPI_IRQ goes from absent to present in NETDEV_CMD_NAPI_GET
replies for this driver.

Could the commit message mention both, or could the banner change be moved
to the patch that actually enables more than one vector?

> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> index 5415ff62a286..a8214c48a775 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c

[ ... ]

> @@ -6005,6 +6087,15 @@ static int rtl_init_phylink(struct rtl8169_private *tp)
>  	return 0;
>  }
>  
> +static void r8169_init_napi(struct rtl8169_private *tp)
> +{
> +	for (int i = 0; i < tp->irq_nvecs; i++) {
> +		netif_napi_add(tp->dev, &tp->rtl8169_napi[i], rtl8169_poll);
> +		netif_napi_set_irq(&tp->rtl8169_napi[i],
> +				   pci_irq_vector(tp->pci_dev, i));
> +	}
> +}
> +

[ ... ]

> @@ -6215,8 +6317,9 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>  			tp->leds = rtl8168_init_leds(dev);
>  	}
>  
> -	netdev_info(dev, "%s, %pM, %sXID %x, IRQ %d\n",
> -		    chip->name, dev->dev_addr, ext_xid_str, xid, tp->irq);
> +	netdev_info(dev, "%s, %pM, %sXID %x, IRQ %d (%u total)\n",
> +		    chip->name, dev->dev_addr, ext_xid_str, xid,
> +		    pci_irq_vector(pdev, 0), tp->irq_nvecs);

[ ... ]

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