[PATCH 3.16.y-ckt 101/165] qlge: Fix qlge_update_hw_vlan_features to handle if interface is down

[Luis Henriques]

3.16.7-ckt9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marcelo Leitner <mleitner at redhat.com>

commit 61132bf7fbe3a802df1f68ad08e8ca10d6b30ddc upstream.

Currently qlge_update_hw_vlan_features() will always first put the
interface down, then update features and then bring it up again. But it
is possible to hit this code while the adapter is down and this causes a
non-paired call to napi_disable(), which will get stuck.

This patch fixes it by skipping these down/up actions if the interface
is already down.

Fixes: a45adbe8d352 ("qlge: Enhance nested VLAN (Q-in-Q) handling.")
Cc: Harish Patil <harish.patil at qlogic.com>
Signed-off-by: Marcelo Ricardo Leitner <mleitner at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/qlogic/qlge/qlge_main.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlge/qlge_main.c b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
index b40050e03a56..078da66132d5 100644
--- a/drivers/net/ethernet/qlogic/qlge/qlge_main.c
+++ b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
@@ -2351,23 +2351,29 @@ static int qlge_update_hw_vlan_features(struct net_device *ndev,
 {
 	struct ql_adapter *qdev = netdev_priv(ndev);
 	int status = 0;
+	bool need_restart = netif_running(ndev);
 
-	status = ql_adapter_down(qdev);
-	if (status) {
-		netif_err(qdev, link, qdev->ndev,
-			  "Failed to bring down the adapter\n");
-		return status;
+	if (need_restart) {
+		status = ql_adapter_down(qdev);
+		if (status) {
+			netif_err(qdev, link, qdev->ndev,
+				  "Failed to bring down the adapter\n");
+			return status;
+		}
 	}
 
 	/* update the features with resent change */
 	ndev->features = features;
 
-	status = ql_adapter_up(qdev);
-	if (status) {
-		netif_err(qdev, link, qdev->ndev,
-			  "Failed to bring up the adapter\n");
-		return status;
+	if (need_restart) {
+		status = ql_adapter_up(qdev);
+		if (status) {
+			netif_err(qdev, link, qdev->ndev,
+				  "Failed to bring up the adapter\n");
+			return status;
+		}
 	}
+
 	return status;
 }