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Date:   Fri, 31 Mar 2023 08:02:21 +0200
From:   Wolfram Sang <wsa+renesas@sang-engineering.com>
To:     Steen.Hegelund@microchip.com
Cc:     netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        steve.glendinning@shawell.net, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        geert+renesas@glider.be, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] smsc911x: only update stats when interface is up
Message-ID: <ZCZ3bSlOF9Sm4DJ2@ninjato>
Mail-Followup-To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Steen.Hegelund@microchip.com, netdev@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, steve.glendinning@shawell.net,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, geert+renesas@glider.be,
        linux-kernel@vger.kernel.org
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> > +       if (pdata->is_open) {
>=20
> Couldn't you just use netif_carrier_ok() here and drop the is_open
> variable?

=46rom my research, I can't:

1) netif_carrier_ok() uses __LINK_STATE_NOCARRIER
2) __LINK_STATE_NOCARRIER gets cleared in netif_carrier_on()
3) netif_carrier_on() is this code:

	if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
		if (dev->reg_state =3D=3D NETREG_UNINITIALIZED)
			return;
		atomic_inc(&dev->carrier_up_count);
		linkwatch_fire_event(dev);
		if (netif_running(dev))
			__netdev_watchdog_up(dev);
	}

4) Notice the last if. It checks netif_running(). So, it is possible to
have the carrier on and the device not opened yet.
5) Sadly, no cigar. If I didn't miss something...

But thanks for the suggestion! Happy hacking,

   Wolfram


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