IB: Support ib_flow creation in drivers

This patch considers the case that ib_flow is created by some device
driver with its specific parameters using the KABI infrastructure.

In that case both QP and ib_uflow_resources might not be applicable.
Downstream patches from this series use the above functionality.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -2771,6 +2771,9 @@ void ib_uverbs_flow_resources_free(struct ib_uflow_resources *uflow_res)
 {
 	unsigned int i;
 
+	if (!uflow_res)
+		return;
+
 	for (i = 0; i < uflow_res->collection_num; i++)
 		atomic_dec(&uflow_res->collection[i]->usecnt);
 
@@ -3585,6 +3588,7 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 	}
 	atomic_inc(&qp->usecnt);
 	flow_id->qp = qp;
+	flow_id->device = qp->device;
 	flow_id->uobject = uobj;
 	uobj->object = flow_id;
 	uflow = container_of(uobj, typeof(*uflow), uobject);

drivers/infiniband/core/uverbs_std_types.c

@@ -54,9 +54,10 @@ static int uverbs_free_flow(struct ib_uobject *uobject,
 	struct ib_qp *qp = flow->qp;
 	int ret;
 
-	ret = qp->device->destroy_flow(flow);
+	ret = flow->device->destroy_flow(flow);
 	if (!ret) {
-		atomic_dec(&qp->usecnt);
+		if (qp)
+			atomic_dec(&qp->usecnt);
 		ib_uverbs_flow_resources_free(uflow->resources);
 	}
 

include/rdma/ib_verbs.h

@@ -2081,6 +2081,7 @@ struct ib_flow_attr {
 
 struct ib_flow {
 	struct ib_qp		*qp;
+	struct ib_device	*device;
 	struct ib_uobject	*uobject;
 };