[PATCH 5.4 5/6] RDMA/mlx5: Block FDB rules when not in switchdev mode

[Sasha Levin <sashal@kernel.org>]

From: Mark Bloch <mbloch@nvidia.com>

commit edc0b0bccc9c80d9a44d3002dcca94984b25e7cf upstream.

Allow creating FDB steering rules only when in switchdev mode.

The only software model where a userspace application can manipulate
FDB entries is when it manages the eswitch. This is only possible in
switchdev mode where we expose a single RDMA device with representors
for all the vports that are connected to the eswitch.

Fixes: 52438be44112 ("RDMA/mlx5: Allow inserting a steering rule to the FDB")
Link: https://lore.kernel.org/r/e928ae7c58d07f104716a2a8d730963d1bd01204.1623052923.git.leonro@nvidia.com
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[sudip: manually backport to old file]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/hw/mlx5/flow.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/infiniband/hw/mlx5/flow.c b/drivers/infiniband/hw/mlx5/flow.c
index b198ff10cde9..fddefb29efd7 100644
--- a/drivers/infiniband/hw/mlx5/flow.c
+++ b/drivers/infiniband/hw/mlx5/flow.c
@@ -13,6 +13,7 @@
 #include <rdma/ib_umem.h>
 #include <linux/mlx5/driver.h>
 #include <linux/mlx5/fs.h>
+#include <linux/mlx5/eswitch.h>
 #include "mlx5_ib.h"
 
 #define UVERBS_MODULE_NAME mlx5_ib
@@ -316,6 +317,13 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_FLOW_MATCHER_CREATE)(
 	if (err)
 		goto end;
 
+	if (obj->ns_type == MLX5_FLOW_NAMESPACE_FDB &&
+	    mlx5_eswitch_mode(dev->mdev->priv.eswitch) !=
+			      MLX5_ESWITCH_OFFLOADS) {
+		err = -EINVAL;
+		goto end;
+	}
+
 	uobj->object = obj;
 	obj->mdev = dev->mdev;
 	atomic_set(&obj->usecnt, 0);
-- 
2.30.2