[PATCH 3.16 064/204] Revert "IB/ipoib: Update broadcast object if PKey value was changed in index 0"

[Ben Hutchings]

3.16.52-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Alex Estrin <alex.estrin@xxxxxxxxx>

commit 612601d0013f03de9dc134809f242ba6da9ca252 upstream.

commit 9a9b8112699d will cause core to fail UD QP from being destroyed
on ipoib unload, therefore cause resources leakage.
On pkey change event above patch modifies mgid before calling underlying
driver to detach it from QP. Drivers' detach_mcast() will fail to find
modified mgid it was never given to attach in a first place.
Core qp->usecnt will never go down, so ib_destroy_qp() will fail.

IPoIB driver actually does take care of new broadcast mgid based on new
pkey by destroying an old mcast object in ipoib_mcast_dev_flush())
....
	if (priv->broadcast) {
		rb_erase(&priv->broadcast->rb_node, &priv->multicast_tree);
		list_add_tail(&priv->broadcast->list, &remove_list);
		priv->broadcast = NULL;
	}
...

then in restarted ipoib_macst_join_task() creating a new broadcast mcast
object, sending join request and on completion tells the driver to attach
to reinitialized QP:
...
if (!priv->broadcast) {
...
	broadcast = ipoib_mcast_alloc(dev, 0);
...
	memcpy(broadcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
	       sizeof (union ib_gid));
	priv->broadcast = broadcast;
...

Fixes: 9a9b8112699d ("IB/ipoib: Update broadcast object if PKey value was changed in index 0")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Alex Estrin <alex.estrin@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Reviewed-by: Feras Daoud <ferasda@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/infiniband/ulp/ipoib/ipoib_ib.c | 13 -------------
 1 file changed, 13 deletions(-)

--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -961,19 +961,6 @@ static inline int update_parent_pkey(str
 		 */
 		priv->dev->broadcast[8] = priv->pkey >> 8;
 		priv->dev->broadcast[9] = priv->pkey & 0xff;
-
-		/*
-		 * Update the broadcast address in the priv->broadcast object,
-		 * in case it already exists, otherwise no one will do that.
-		 */
-		if (priv->broadcast) {
-			spin_lock_irq(&priv->lock);
-			memcpy(priv->broadcast->mcmember.mgid.raw,
-			       priv->dev->broadcast + 4,
-			sizeof(union ib_gid));
-			spin_unlock_irq(&priv->lock);
-		}
-
 		return 0;
 	}