[PATCH net 1/3] igb: fix RTNL assertion when resuming from runtime suspend

[Antonio Quartulli <antonio@mandelbit.com>]

Since commit ac8c58f5b535 ("igb: fix deadlock caused by taking RTNL in
RPM resume path") __igb_resume() doesn't take RTNL for runtime resume,
but __igb_open() still calls netif_set_real_num_{tx,rx}_queues(), which
require it. An asynchronous runtime resume (e.g. after the link comes
back) then triggers "RTNL: assertion failed".

The queue counts only change on paths that re-open the device under
RTNL (ethtool -L, SR-IOV reconfiguration): set them in igb_open() only,
as igc does since commit 6f31d6b643a3 ("igc: Refactor runtime power
management flow").

Fixes: ac8c58f5b535 ("igb: fix deadlock caused by taking RTNL in RPM resume path")
Cc: stable@vger.kernel.org
Closes: https://bugzilla.ipfire.org/show_bug.cgi?id=13562
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 24 +++++++++++------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 78f0786..bd1185d 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4178,17 +4178,6 @@ static int __igb_open(struct net_device *netdev, bool resuming)
 	if (err)
 		goto err_req_irq;
 
-	/* Notify the stack of the actual queue counts. */
-	err = netif_set_real_num_tx_queues(adapter->netdev,
-					   adapter->num_tx_queues);
-	if (err)
-		goto err_set_queues;
-
-	err = netif_set_real_num_rx_queues(adapter->netdev,
-					   adapter->num_rx_queues);
-	if (err)
-		goto err_set_queues;
-
 	/* From here on the code is the same as igb_up() */
 	clear_bit(__IGB_DOWN, &adapter->state);
 
@@ -4223,8 +4212,6 @@ static int __igb_open(struct net_device *netdev, bool resuming)
 
 	return 0;
 
-err_set_queues:
-	igb_free_irq(adapter);
 err_req_irq:
 	igb_release_hw_control(adapter);
 	igb_power_down_link(adapter);
@@ -4241,6 +4228,17 @@ err_setup_tx:
 
 int igb_open(struct net_device *netdev)
 {
+	struct igb_adapter *adapter = netdev_priv(netdev);
+	int err;
+
+	/* Notify the stack of the actual queue counts. */
+	err = netif_set_real_num_queues(netdev, adapter->num_tx_queues,
+					adapter->num_rx_queues);
+	if (err) {
+		netdev_err(netdev, "error setting real queue count\n");
+		return err;
+	}
+
 	return __igb_open(netdev, false);
 }
 
-- 
2.56.0