[PATCH 5.0 09/36] mlxsw: spectrum_acl: Avoid warning after identical rules insertion

[Greg Kroah-Hartman]

From: Jiri Pirko <j...@mellanox.com>

[ Upstream commit ef74422020aa8c224b00a927e3e47faac4d8fae3 ]

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 <alexand...@mellanox.com>
Fixes: c22291f7cf45 ("mlxsw: spectrum: acl: Implement delta for ERP")
Signed-off-by: Jiri Pirko <j...@mellanox.com>
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
@@ -1169,13 +1169,12 @@ mlxsw_sp_acl_erp_delta_fill(const struct
                        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)];