From: Erez Shitrit <erezsh@mellanox.com>
Date: Wed, 12 Jul 2017 10:40:25 +0300
Subject: IB/ipoib: Use cancel_delayed_work_sync when needed
Patch-mainline: v4.13-rc5
Git-commit: 6bdc8de2e86e717124a715ecc480892a2c331ff5
References: bsc#1046307 FATE#322941

The work mcast_task can re-queue itself, so instead of doing
cancel && flush_workqueue, that still can leave a queued task
on the air, use cancel_delayed_work_sync.

Also, no need to use lock over the cancel, the original lock was
due to bit assignment setting (IPOIB_MCAST_RUN) that is not in use
anymore.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -684,15 +684,10 @@ void ipoib_mcast_start_thread(struct net
 int ipoib_mcast_stop_thread(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
-	unsigned long flags;
 
 	ipoib_dbg_mcast(priv, "stopping multicast thread\n");
 
-	spin_lock_irqsave(&priv->lock, flags);
-	cancel_delayed_work(&priv->mcast_task);
-	spin_unlock_irqrestore(&priv->lock, flags);
-
-	flush_workqueue(priv->wq);
+	cancel_delayed_work_sync(&priv->mcast_task);
 
 	return 0;
 }