IB/ehca: Fix improper use of yield() with spinlock held

Signed-off-by: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ehca/ehca_cq.c

@@ -344,8 +344,11 @@ int ehca_destroy_cq(struct ib_cq *cq)
 	unsigned long flags;
 
 	spin_lock_irqsave(&ehca_cq_idr_lock, flags);
-	while (my_cq->nr_callbacks)
+	while (my_cq->nr_callbacks) {
+		spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 		yield();
+		spin_lock_irqsave(&ehca_cq_idr_lock, flags);
+	}
 
 	idr_remove(&ehca_cq_idr, my_cq->token);
 	spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);