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 <hkallwe...@gmail.com>
---
net/core/dev.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 6bc238814..ffa8c371d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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))
- return -ENODEV;
+ 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
--
2.27.0
