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From:   trix@redhat.com
To:     vladimir.oltean@nxp.com, claudiu.manoil@nxp.com,
        alexandre.belloni@bootlin.com, davem@davemloft.net,
        kuba@kernel.org, nathan@kernel.org, ndesaulniers@google.com,
        xiaoliang.yang_1@nxp.com
Cc:     UNGLinuxDriver@microchip.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Tom Rix <trix@redhat.com>
Subject: [PATCH] net: mscc: ocelot: fix using match before it is set
Date:   Tue, 18 Jan 2022 05:41:10 -0800
Message-Id: <20220118134110.591613-1-trix@redhat.com>
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From: Tom Rix <trix@redhat.com>

Clang static analysis reports this issue
ocelot_flower.c:563:8: warning: 1st function call argument
  is an uninitialized value
    !is_zero_ether_addr(match.mask->dst)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The variable match is used before it is set.  So move the
block.

Fixes: 75944fda1dfe ("net: mscc: ocelot: offload ingress skbedit and vlan actions to VCAP IS1")
Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/net/ethernet/mscc/ocelot_flower.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot_flower.c b/drivers/net/ethernet/mscc/ocelot_flower.c
index 4a0fda22d3436..949858891973d 100644
--- a/drivers/net/ethernet/mscc/ocelot_flower.c
+++ b/drivers/net/ethernet/mscc/ocelot_flower.c
@@ -559,13 +559,6 @@ ocelot_flower_parse_key(struct ocelot *ocelot, int port, bool ingress,
 			return -EOPNOTSUPP;
 		}
 
-		if (filter->block_id == VCAP_IS1 &&
-		    !is_zero_ether_addr(match.mask->dst)) {
-			NL_SET_ERR_MSG_MOD(extack,
-					   "Key type S1_NORMAL cannot match on destination MAC");
-			return -EOPNOTSUPP;
-		}
-
 		/* The hw support mac matches only for MAC_ETYPE key,
 		 * therefore if other matches(port, tcp flags, etc) are added
 		 * then just bail out
@@ -580,6 +573,14 @@ ocelot_flower_parse_key(struct ocelot *ocelot, int port, bool ingress,
 			return -EOPNOTSUPP;
 
 		flow_rule_match_eth_addrs(rule, &match);
+
+		if (filter->block_id == VCAP_IS1 &&
+		    !is_zero_ether_addr(match.mask->dst)) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Key type S1_NORMAL cannot match on destination MAC");
+			return -EOPNOTSUPP;
+		}
+
 		filter->key_type = OCELOT_VCAP_KEY_ETYPE;
 		ether_addr_copy(filter->key.etype.dmac.value,
 				match.key->dst);
-- 
2.26.3