mlxsw: spectrum_acl: Avoid warning after identical rules insertion

This change “mlxsw: spectrum_acl: Avoid warning after identical rules insertion” (commit ef74422) in Linux kernel is authored by Jiri Pirko <jiri [at] mellanox.com> on Wed May 29 10:59:44 2019 +0300.

Description of "mlxsw: spectrum_acl: Avoid warning after identical rules insertion"

The change “mlxsw: spectrum_acl: Avoid warning after identical rules insertion” introduces changes as follows.

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>

Linux kernel releases containing commit ef74422

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "mlxsw: spectrum_acl: Avoid warning after identical rules insertion"

There are 11 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 .../net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c    | 11 +++++------
 1 file 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)];

The commit for this change in Linux stable tree is ef74422 (patch).

Last modified: 2020/02/08