mlxsw: spectrum_acl: Avoid warning after identical rules insertion

When identical rules are inserted, the latter one goes to C-TCAM. For
that, a second eRP with the same mask is created. These 2 eRPs by the
nature cannot be merged and also one cannot be parent of another.
Teach mlxsw_sp_acl_erp_delta_fill() about this possibility and handle it
gracefully.

Reported-by: Alex Kushnarov <alexanderk@mellanox.com>
Fixes: c22291f7cf45 ("mlxsw: spectrum: acl: Implement delta for ERP")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
index c1a9cc9a3292..4c98950380d5 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
@@ -1171,13 +1171,12 @@ mlxsw_sp_acl_erp_delta_fill(const struct mlxsw_sp_acl_erp_key *parent_key,
                         return -EINVAL;
         }
         if (si == -1) {
-                /* The masks are the same, this cannot happen.
-                 * That means the caller is broken.
+                /* The masks are the same, this can happen in case eRPs with
+                 * the same mask were created in both A-TCAM and C-TCAM.
+                 * The only possible condition under which this can happen
+                 * is identical rule insertion. Delta is not possible here.
                  */
-                WARN_ON(1);
-                *delta_start = 0;
-                *delta_mask = 0;
-                return 0;
+                return -EINVAL;
         }
         pmask = (unsigned char) parent_key->mask[__MASK_IDX(si)];
         mask = (unsigned char) key->mask[__MASK_IDX(si)];