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Subject[PATCH 1/2] igb: Use device_lock() insead of rtnl_lock()
Date
Commit 9474933caf21 ("igb: close/suspend race in netif_device_detach")
fixed race condition between close and power management ops by using
rtnl_lock().

However we can achieve the same by using device_lock() since all power
management ops are protected by device_lock().

This fix is a preparation for next patch, to prevent a dead lock under
rtnl_lock() when calling runtime resume routine.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
drivers/net/ethernet/intel/igb/igb_main.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index b46bff8fe056..3750e2b926b1 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4026,8 +4026,13 @@ static int __igb_close(struct net_device *netdev, bool suspending)

int igb_close(struct net_device *netdev)
{
+ struct igb_adapter *adapter = netdev_priv(netdev);
+ struct device *dev = &adapter->pdev->dev;
+
+ device_lock(dev);
if (netif_device_present(netdev) || netdev->dismantle)
return __igb_close(netdev, false);
+ device_unlock(dev);
return 0;
}

@@ -8760,7 +8765,6 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake,
u32 wufc = runtime ? E1000_WUFC_LNKC : adapter->wol;
bool wake;

- rtnl_lock();
netif_device_detach(netdev);

if (netif_running(netdev))
@@ -8769,7 +8773,6 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake,
igb_ptp_suspend(adapter);

igb_clear_interrupt_scheme(adapter);
- rtnl_unlock();

status = rd32(E1000_STATUS);
if (status & E1000_STATUS_LU)
@@ -8897,13 +8900,11 @@ static int __maybe_unused igb_resume(struct device *dev)

wr32(E1000_WUS, ~0);

- rtnl_lock();
if (!err && netif_running(netdev))
err = __igb_open(netdev, true);

if (!err)
netif_device_attach(netdev);
- rtnl_unlock();

return err;
}
--
2.17.1
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