[net-next 3/6] ixgbe: release lock for the duration of ixgbe_suspend_close()

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Pavel Tatashin <pasha.tatashin@oracle.com>

Currently, during device_shutdown() ixgbe holds rtnl_lock for the duration
of lengthy ixgbe_close_suspend(). On machines with multiple ixgbe cards
this lock prevents scaling if device_shutdown() function is multi-threaded.

It is not necessary to hold this lock during ixgbe_close_suspend()
as it is not held when ixgbe_close() is called also during shutdown but for
kexec case.

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index a52d92e182ee..5ddfb93ed491 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -6698,8 +6698,15 @@ static int __ixgbe_shutdown(struct pci_dev *pdev, bool *enable_wake)
 	rtnl_lock();
 	netif_device_detach(netdev);
 
-	if (netif_running(netdev))
+	if (netif_running(netdev)) {
+		/* Suspend takes a long time, device_shutdown may be
+		 * parallelized this function, so drop lock for the
+		 * duration of this call.
+		 */
+		rtnl_unlock();
 		ixgbe_close_suspend(adapter);
+		rtnl_lock();
+	}
 
 	ixgbe_clear_interrupt_scheme(adapter);
 	rtnl_unlock();
-- 
2.17.0