Commit bd869245 authored Jun 20, 2020 by Heiner Kallweit Committed by David S. Miller Jun 22, 2020

net: core: try to runtime-resume detached device in __dev_open



A netdevice may be marked as detached because the parent is
runtime-suspended and not accessible whilst interface or link is down.
An example are PCI network devices that go into PCI D3hot, see e.g.
__igc_shutdown() or rtl8169_net_suspend().
If netdevice is down and marked as detached we can only open it if
we runtime-resume it before __dev_open() calls netif_device_present().

Therefore, if netdevice is detached, try to runtime-resume the parent
and only return with an error if it's still detached.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 8878adba

net/core/dev.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -143,6 +143,7 @@
		#include <linux/net_namespace.h>
		#include <linux/indirect_call_wrapper.h>
		#include <net/devlink.h>
		#include <linux/pm_runtime.h>

		#include "net-sysfs.h"

		@@ -1492,8 +1493,13 @@ static int __dev_open(struct net_device dev, struct netlink_ext_ack extack)

		ASSERT_RTNL();

		if (!netif_device_present(dev)) {
		/* may be detached because parent is runtime-suspended */
		if (dev->dev.parent)
		pm_runtime_resume(dev->dev.parent);
		if (!netif_device_present(dev))
		return -ENODEV;
		}

		/* Block netpoll from trying to do any rx path servicing.
		* If we don't do this there is a chance ndo_poll_controller

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