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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Alex Kushnarov <alexanderk@mellanox.com>,
        Jiri Pirko <jiri@mellanox.com>,
        Ido Schimmel <idosch@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.0 09/36] mlxsw: spectrum_acl: Avoid warning after identical rules insertion
Date:   Mon,  3 Jun 2019 11:08:57 +0200
Message-Id: <20190603090521.569034163@linuxfoundation.org>
In-Reply-To: <20190603090520.998342694@linuxfoundation.org>
References: <20190603090520.998342694@linuxfoundation.org>
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From: Jiri Pirko <jiri@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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@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)];