netdev - [net-next 3/6] ixgbe: release lock for the duration of ixgbe_suspend

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Date:   Thu, 17 May 2018 09:37:29 -0700
From:   Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:     davem@...emloft.net
Cc:     Pavel Tatashin <pasha.tatashin@...cle.com>, netdev@...r.kernel.org,
        nhorman@...hat.com, sassmann@...hat.com, jogreene@...hat.com,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 3/6] ixgbe: release lock for the duration of ixgbe_suspend_close()

From: Pavel Tatashin <pasha.tatashin@...cle.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@...cle.com>
Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.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