[PATCH 4.17 14/42] net/mlx5e: Properly check if hairpin is possible between two functions

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.17-stable review patch.  If anyone has any objections, please let me know.

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

From: Or Gerlitz <ogerlitz@mellanox.com>

[ Upstream commit 816f670623692b5da2787f278cbfdb331ed29b8a ]

The current check relies on function BDF addresses and can get
us wrong e.g when two VFs are assigned into a VM and the PCI
v-address is set by the hypervisor.

Fixes: 5c65c564c962 ('net/mlx5e: Support offloading TC NIC hairpin flows')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Alaa Hleihel <alaa@mellanox.com>
Tested-by: Alaa Hleihel <alaa@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1907,15 +1907,15 @@ static bool actions_match_supported(stru
 static bool same_hw_devs(struct mlx5e_priv *priv, struct mlx5e_priv *peer_priv)
 {
 	struct mlx5_core_dev *fmdev, *pmdev;
-	u16 func_id, peer_id;
+	u64 fsystem_guid, psystem_guid;
 
 	fmdev = priv->mdev;
 	pmdev = peer_priv->mdev;
 
-	func_id = (u16)((fmdev->pdev->bus->number << 8) | PCI_SLOT(fmdev->pdev->devfn));
-	peer_id = (u16)((pmdev->pdev->bus->number << 8) | PCI_SLOT(pmdev->pdev->devfn));
+	mlx5_query_nic_vport_system_image_guid(fmdev, &fsystem_guid);
+	mlx5_query_nic_vport_system_image_guid(pmdev, &psystem_guid);
 
-	return (func_id == peer_id);
+	return (fsystem_guid == psystem_guid);
 }
 
 static int parse_tc_nic_actions(struct mlx5e_priv *priv, struct tcf_exts *exts,