IB/rxe: put the pool on allocation failure

[ Upstream commit 6b9f8970 ]

If the allocation of elem fails, it is not sufficient to simply check
for NULL and return.  We need to also put our reference on the pool or
else we will leave the pool with a permanent ref count and we will never
be able to free it.

Fixes: 4831ca9e ("IB/rxe: check for allocation failure on elem")
Suggested-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/infiniband/sw/rxe/rxe_pool.c

@@ -394,23 +394,25 @@ void *rxe_alloc(struct rxe_pool *pool)
 
 	kref_get(&pool->rxe->ref_cnt);
 
-	if (atomic_inc_return(&pool->num_elem) > pool->max_elem) {
-		atomic_dec(&pool->num_elem);
-		rxe_dev_put(pool->rxe);
-		rxe_pool_put(pool);
-		return NULL;
-	}
+	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
+		goto out_put_pool;
 
 	elem = kmem_cache_zalloc(pool_cache(pool),
 				 (pool->flags & RXE_POOL_ATOMIC) ?
 				 GFP_ATOMIC : GFP_KERNEL);
 	if (!elem)
-		return NULL;
+		goto out_put_pool;
 
 	elem->pool = pool;
 	kref_init(&elem->ref_cnt);
 
 	return elem;
+
+out_put_pool:
+	atomic_dec(&pool->num_elem);
+	rxe_dev_put(pool->rxe);
+	rxe_pool_put(pool);
+	return NULL;
 }
 
 void rxe_elem_release(struct kref *kref)