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Commit 962121b4 authored by Roland Dreier's avatar Roland Dreier
Browse files

Revert "IPoIB: fix mcast_dev_flush/mcast_restart_task race" 



This reverts commit e5d1dcf1.

The series of IPoIB bug fixes that went into 3.19-rc1 introduce
regressions, and after trying to sort things out, we decided to revert
to 3.18's IPoIB driver and get things right for 3.20.

Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent bb759634

drivers/infiniband/ulp/ipoib/ipoib_multicast.c

+5 −32
Original line number Diff line number Diff line
@@ -802,10 +802,7 @@ void ipoib_mcast_dev_flush(struct net_device *dev) 


	spin_unlock_irqrestore(&priv->lock, flags);



	/*

	 * make sure the in-flight joins have finished before we attempt

	 * to leave

	 */

	/* seperate between the wait to the leave*/

	list_for_each_entry_safe(mcast, tmcast, &remove_list, list)

		if (test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))

			wait_for_completion(&mcast->done);
@@ -926,38 +923,14 @@ void ipoib_mcast_restart_task(struct work_struct *work) 
	netif_addr_unlock(dev);

	local_irq_restore(flags);



	/*

	 * make sure the in-flight joins have finished before we attempt

	 * to leave

	 */

	list_for_each_entry_safe(mcast, tmcast, &remove_list, list)

		if (test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))

			wait_for_completion(&mcast->done);



	/*

	 * We have to cancel outside of the spinlock, but we have to

	 * take the rtnl lock or else we race with the removal of

	 * entries from the remove list in mcast_dev_flush as part

	 * of ipoib_stop() which will call mcast_stop_thread with

	 * flush == 1 while holding the rtnl lock, and the

	 * flush_workqueue won't complete until this restart_mcast_task

	 * completes.  So do like the carrier on task and attempt to

	 * take the rtnl lock, but if we can't before the ADMIN_UP flag

	 * goes away, then just return and know that the remove list will

	 * get flushed later by mcast_dev_flush.

	 */

	while (!rtnl_trylock()) {

		if (!test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))

			return;

		else

			msleep(20);

	}

	/* We have to cancel outside of the spinlock */

	list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {

		ipoib_mcast_leave(mcast->dev, mcast);

		ipoib_mcast_free(mcast);

	}



	if (test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))

		ipoib_mcast_start_thread(dev);

	rtnl_unlock();

}



#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG