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Date:   Wed, 25 Oct 2023 17:28:24 +0100
From:   Simon Horman <horms@kernel.org>
To:     Douglas Anderson <dianders@chromium.org>
Cc:     Jakub Kicinski <kuba@kernel.org>,
        Hayes Wang <hayeswang@realtek.com>,
        "David S . Miller" <davem@davemloft.net>,
        Edward Hill <ecgh@chromium.org>,
        Laura Nao <laura.nao@collabora.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        linux-usb@vger.kernel.org, Grant Grundler <grundler@chromium.org>,
        =?utf-8?B?QmrDuHJu?= Mork <bjorn@mork.no>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org
Subject: Re: [PATCH v5 8/8] r8152: Block future register access if register
 access fails
Message-ID: <20231025162824.GK57304@kernel.org>
References: <20231020210751.3415723-1-dianders@chromium.org>
 <20231020140655.v5.8.Ib2affdbfdc2527aaeef9b46d4f23f7c04147faeb@changeid>
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In-Reply-To: <20231020140655.v5.8.Ib2affdbfdc2527aaeef9b46d4f23f7c04147faeb@changeid>
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On Fri, Oct 20, 2023 at 02:06:59PM -0700, Douglas Anderson wrote:

...

> @@ -9603,25 +9713,14 @@ static bool rtl8152_supports_lenovo_macpassthru(struct usb_device *udev)
>  	return 0;
>  }
>  
> -static int rtl8152_probe(struct usb_interface *intf,
> -			 const struct usb_device_id *id)
> +static int rtl8152_probe_once(struct usb_interface *intf,
> +			      const struct usb_device_id *id, u8 version)
>  {
>  	struct usb_device *udev = interface_to_usbdev(intf);
>  	struct r8152 *tp;
>  	struct net_device *netdev;
> -	u8 version;
>  	int ret;
>  
> -	if (intf->cur_altsetting->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
> -		return -ENODEV;
> -
> -	if (!rtl_check_vendor_ok(intf))
> -		return -ENODEV;
> -
> -	version = rtl8152_get_version(intf);
> -	if (version == RTL_VER_UNKNOWN)
> -		return -ENODEV;
> -
>  	usb_reset_device(udev);
>  	netdev = alloc_etherdev(sizeof(struct r8152));
>  	if (!netdev) {
> @@ -9784,10 +9883,20 @@ static int rtl8152_probe(struct usb_interface *intf,
>  	else
>  		device_set_wakeup_enable(&udev->dev, false);
>  
> +	/* If we saw a control transfer error while probing then we may
> +	 * want to try probe() again. Consider this an error.
> +	 */
> +	if (test_bit(PROBE_SHOULD_RETRY, &tp->flags))
> +		goto out2;

Sorry for being a bit slow here, but if this is an error condition,
sould ret be set to an error value?

As flagged by Smatch.

> +
> +	set_bit(PROBED_WITH_NO_ERRORS, &tp->flags);
>  	netif_info(tp, probe, netdev, "%s\n", DRIVER_VERSION);
>  
>  	return 0;
>  
> +out2:
> +	unregister_netdev(netdev);
> +
>  out1:
>  	tasklet_kill(&tp->tx_tl);
>  	cancel_delayed_work_sync(&tp->hw_phy_work);

...