Messages in this thread Patch in this message | | | From | Kai-Heng Feng <> | Subject | [PATCH] igb: Use a sperate mutex insead of rtnl_lock() | Date | Thu, 26 Mar 2020 18:39:26 +0800 |
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Commit 9474933caf21 ("igb: close/suspend race in netif_device_detach") fixed race condition between close and power management ops by using rtnl_lock().
This fix is a preparation for next patch, to prevent a dead lock under rtnl_lock() when calling runtime resume routine.
However, we can't use device_lock() in igb_close() because when module is getting removed, the lock is already held for igb_remove(), and igb_close() gets called during unregistering the netdev, hence causing a deadlock. So let's introduce a new mutex so we don't cause a deadlock with driver core or netdev core.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> --- drivers/net/ethernet/intel/igb/igb_main.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index b46bff8fe056..dc7ed5dd216b 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -288,6 +288,8 @@ static const struct igb_reg_info igb_reg_info_tbl[] = { {} }; +static DEFINE_MUTEX(igb_mutex); + /* igb_regdump - register printout routine */ static void igb_regdump(struct e1000_hw *hw, struct igb_reg_info *reginfo) { @@ -4026,9 +4028,14 @@ static int __igb_close(struct net_device *netdev, bool suspending) int igb_close(struct net_device *netdev) { + int err = 0; + + mutex_lock(&igb_mutex); if (netif_device_present(netdev) || netdev->dismantle) - return __igb_close(netdev, false); - return 0; + err = __igb_close(netdev, false); + mutex_unlock(&igb_mutex); + + return err; } /** @@ -8760,7 +8767,7 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake, u32 wufc = runtime ? E1000_WUFC_LNKC : adapter->wol; bool wake; - rtnl_lock(); + mutex_lock(&igb_mutex); netif_device_detach(netdev); if (netif_running(netdev)) @@ -8769,7 +8776,7 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake, igb_ptp_suspend(adapter); igb_clear_interrupt_scheme(adapter); - rtnl_unlock(); + mutex_unlock(&igb_mutex); status = rd32(E1000_STATUS); if (status & E1000_STATUS_LU) @@ -8897,13 +8904,13 @@ static int __maybe_unused igb_resume(struct device *dev) wr32(E1000_WUS, ~0); - rtnl_lock(); + mutex_lock(&igb_mutex); if (!err && netif_running(netdev)) err = __igb_open(netdev, true); if (!err) netif_device_attach(netdev); - rtnl_unlock(); + mutex_unlock(&igb_mutex); return err; } -- 2.17.1
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