octeontx2-af: Check return value of nix_get_nixlf before using nixlf

If a NIXLF is not attached to a PF/VF device then
nix_get_nixlf function fails and returns proper error
code. But npc_get_default_entry_action does not check it
and uses garbage value in subsequent calls. Fix this
by cheking the return value of nix_get_nixlf.

Fixes: 967db35 ("octeontx2-af: add support for multicast/promisc packet replication feature")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Subbaraya Sundeep

drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c

@@ -389,7 +389,13 @@ static u64 npc_get_default_entry_action(struct rvu *rvu, struct npc_mcam *mcam,
 	int bank, nixlf, index;
 
 	/* get ucast entry rule entry index */
-	nix_get_nixlf(rvu, pf_func, &nixlf, NULL);
+	if (nix_get_nixlf(rvu, pf_func, &nixlf, NULL)) {
+		dev_err(rvu->dev, "%s: nixlf not attached to pcifunc:0x%x\n",
+			__func__, pf_func);
+		/* Action 0 is drop */
+		return 0;
+	}
+
 	index = npc_get_nixlf_mcam_index(mcam, pf_func, nixlf,
 					 NIXLF_UCAST_ENTRY);
 	bank = npc_get_bank(mcam, index);