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Date:   Mon, 24 May 2021 11:13:42 +0200
From:   Johan Hovold <johan@kernel.org>
To:     Hayes Wang <hayeswang@realtek.com>
Cc:     "kuba@kernel.org" <kuba@kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        nic_swsd <nic_swsd@realtek.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "syzbot+95afd23673f5dd295c57@syzkaller.appspotmail.com" 
        <syzbot+95afd23673f5dd295c57@syzkaller.appspotmail.com>
Subject: Re: [PATCH net v3] r8152: check the informaton of the device
Message-ID: <YKtuRmp6mC34kf2k@hovoldconsulting.com>
References: <1394712342-15778-363-Taiwan-albertk@realtek.com>
 <1394712342-15778-365-Taiwan-albertk@realtek.com>
 <YKtdJnvZTxE1yqEK@hovoldconsulting.com>
 <1e7e1d4039724eb4bcdd5884a748d880@realtek.com>
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On Mon, May 24, 2021 at 08:54:50AM +0000, Hayes Wang wrote:
> Johan Hovold <johan@kernel.org>
> > Sent: Monday, May 24, 2021 4:01 PM
> [...]
> > >  	/* The vendor mode is not always config #1, so to find it out. */
> > >  	udev = interface_to_usbdev(intf);
> > >  	c = udev->config;
> > >  	num_configs = udev->descriptor.bNumConfigurations;
> > > +	if (num_configs < 2)
> > > +		return false;
> > > +
> > 
> > Nit: This check looks unnecessary also as the driver can handle a single
> > configuration just fine, and by removing it you'd be logging "Unexpected
> > Device\n" below also in the single config case.
> 
> I just want to distinguish the devices.
> It is acceptable if the device contains only one configuration.
> A mistake occurs if the device has more configurations and
> there is no expected one.
> I would remove it if you think it is better.

I'm fine with keeping the check too (e.g. as an optimisation of sort),
it's just a bit inconsistent to not log an error in that one error path.

Johan