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From:   Pavel Tatashin <pasha.tatashin@oracle.com>
To:     pasha.tatashin@oracle.com, steven.sistare@oracle.com,
        daniel.m.jordan@oracle.com, linux-kernel@vger.kernel.org,
        jeffrey.t.kirsher@intel.com, intel-wired-lan@lists.osuosl.org,
        netdev@vger.kernel.org, gregkh@linuxfoundation.org
Subject: [PATCH 1/2] ixgbe: release lock for the duration of ixgbe_suspend_close()
Date:   Wed,  2 May 2018 23:59:30 -0400
Message-Id: <20180503035931.22439-2-pasha.tatashin@oracle.com>
In-Reply-To: <20180503035931.22439-1-pasha.tatashin@oracle.com>
References: <20180503035931.22439-1-pasha.tatashin@oracle.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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>
---
 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 afadba99f7b8..e7875b58854b 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -6748,8 +6748,15 @@ 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