netdev - Re: lan78xx and phy_state

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Message-ID: <20191016155107.GH17013@lunn.ch>
Date:   Wed, 16 Oct 2019 17:51:07 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Daniel Wagner <dwagner@...e.de>
Cc:     bcm-kernel-feedback-list@...adcom.com,
        linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        Woojung Huh <woojung.huh@...rochip.com>,
        UNGLinuxDriver@...rochip.com, netdev@...r.kernel.org
Subject: Re: lan78xx and phy_state_machine

Hi Daniel

Please could you give this a go. It is totally untested, not even
compile tested...

Thanks
	Andrew

>From 235549a687ad91c1500289fb32ee1c775d06d16d Mon Sep 17 00:00:00 2001
From: Andrew Lunn <andrew@...n.ch>
Date: Wed, 16 Oct 2019 10:42:07 -0500
Subject: [PATCH] net: usb: lan78xx: Connect PHY before registering MAC

As soon as the netdev is registers, the kernel can start using the
interface. If the driver connects the MAC to the PHY after the netdev
is registered, there is a race condition where the interface can be
opened without having the PHY connected.

Change the order to close this race condition.

Fixes: 92571a1aae40 ("lan78xx: Connect phy early")
Reported-by: Daniel Wagner <dwagner@...e.de>
Signed-off-by: Andrew Lunn <andrew@...n.ch>
---
 drivers/net/usb/lan78xx.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 58f5a219fb65..62948098191f 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3782,10 +3782,14 @@ static int lan78xx_probe(struct usb_interface *intf,
 	/* driver requires remote-wakeup capability during autosuspend. */
 	intf->needs_remote_wakeup = 1;
 
+	ret = lan78xx_phy_init(dev);
+	if (ret < 0)
+		goto out4;
+
 	ret = register_netdev(netdev);
 	if (ret != 0) {
 		netif_err(dev, probe, netdev, "couldn't register the device\n");
-		goto out4;
+		goto out5;
 	}
 
 	usb_set_intfdata(intf, dev);
@@ -3798,14 +3802,10 @@ static int lan78xx_probe(struct usb_interface *intf,
 	pm_runtime_set_autosuspend_delay(&udev->dev,
 					 DEFAULT_AUTOSUSPEND_DELAY);
 
-	ret = lan78xx_phy_init(dev);
-	if (ret < 0)
-		goto out5;
-
 	return 0;
 
 out5:
-	unregister_netdev(netdev);
+	phy_disconnect(netdev->phydev);
 out4:
 	usb_free_urb(dev->urb_intr);
 out3:
-- 
2.23.0