Subject: [net 05/10] net/mlx5: Correctly compare pkt reformat ids

From: Saeed Mahameed <[email-masked]>
Date: Tue, 26 Mar 2024 07:46:41 -0700

From: Cosmin Ratiu <[email-masked]>

struct mlx5_pkt_reformat contains a naked union of a u32 id and a
dr_action pointer which is used when the action is SW-managed (when
pkt_reformat.owner is set to MLX5_FLOW_RESOURCE_OWNER_SW). Using id
directly in that case is incorrect, as it maps to the least significant
32 bits of the 64-bit pointer in mlx5_fs_dr_action and not to the pkt
reformat id allocated in firmware.

For the purpose of comparing whether two rules are identical,
interpreting the least significant 32 bits of the mlx5_fs_dr_action
pointer as an id mostly works... until it breaks horribly and produces
the outcome described in [1].

This patch fixes mlx5_flow_dests_cmp to correctly compare ids using
mlx5_fs_dr_action_get_pkt_reformat_id for the SW-managed rules.

Link: https://lore.kernel.org/netdev/[email-masked]/T/#u [1]

Fixes: 6a48faeeca10 ("net/mlx5: Add direct rule fs_cmd implementation")
Signed-off-by: Cosmin Ratiu <[email-masked]>
Reviewed-by: Mark Bloch <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 2a9421342a50..cf085a478e3e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1664,6 +1664,16 @@ static int create_auto_flow_group(struct mlx5_flow_table *ft,
 	return err;
 }
 
+static bool mlx5_pkt_reformat_cmp(struct mlx5_pkt_reformat *p1,
+				  struct mlx5_pkt_reformat *p2)
+{
+	return p1->owner == p2->owner &&
+		(p1->owner == MLX5_FLOW_RESOURCE_OWNER_FW ?
+		 p1->id == p2->id :
+		 mlx5_fs_dr_action_get_pkt_reformat_id(p1) ==
+		 mlx5_fs_dr_action_get_pkt_reformat_id(p2));
+}
+
 static bool mlx5_flow_dests_cmp(struct mlx5_flow_destination *d1,
 				struct mlx5_flow_destination *d2)
 {
@@ -1675,8 +1685,8 @@ static bool mlx5_flow_dests_cmp(struct mlx5_flow_destination *d1,
 		     ((d1->vport.flags & MLX5_FLOW_DEST_VPORT_VHCA_ID) ?
 		      (d1->vport.vhca_id == d2->vport.vhca_id) : true) &&
 		     ((d1->vport.flags & MLX5_FLOW_DEST_VPORT_REFORMAT_ID) ?
-		      (d1->vport.pkt_reformat->id ==
-		       d2->vport.pkt_reformat->id) : true)) ||
+		      mlx5_pkt_reformat_cmp(d1->vport.pkt_reformat,
+					    d2->vport.pkt_reformat) : true)) ||
 		    (d1->type == MLX5_FLOW_DESTINATION_TYPE_FLOW_TABLE &&
 		     d1->ft == d2->ft) ||
 		    (d1->type == MLX5_FLOW_DESTINATION_TYPE_TIR &&
-- 
2.44.0