net/bpf_jit: MIPS: split VLAN_PRESENT bit handling from VLAN_TCI

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/mips/net/bpf_jit.c

@@ -1159,19 +1159,22 @@ static int build_body(struct jit_ctx *ctx)
 			emit_load(r_A, r_skb, off, ctx);
 			break;
 		case BPF_ANC | SKF_AD_VLAN_TAG:
-		case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
 			ctx->flags |= SEEN_SKB | SEEN_A;
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
 						  vlan_tci) != 2);
 			off = offsetof(struct sk_buff, vlan_tci);
-			emit_half_load_unsigned(r_s0, r_skb, off, ctx);
-			if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
-				emit_andi(r_A, r_s0, (u16)~VLAN_TAG_PRESENT, ctx);
-			} else {
-				emit_andi(r_A, r_s0, VLAN_TAG_PRESENT, ctx);
-				/* return 1 if present */
-				emit_sltu(r_A, r_zero, r_A, ctx);
-			}
+			emit_half_load_unsigned(r_A, r_skb, off, ctx);
+#ifdef VLAN_TAG_PRESENT
+			emit_andi(r_A, r_A, (u16)~VLAN_TAG_PRESENT, ctx);
+#endif
+			break;
+		case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
+			ctx->flags |= SEEN_SKB | SEEN_A;
+			emit_load_byte(r_A, r_skb, PKT_VLAN_PRESENT_OFFSET(), ctx);
+			if (PKT_VLAN_PRESENT_BIT)
+				emit_srl(r_A, r_A, PKT_VLAN_PRESENT_BIT, ctx);
+			if (PKT_VLAN_PRESENT_BIT < 7)
+				emit_andi(r_A, r_A, 1, ctx);
 			break;
 		case BPF_ANC | SKF_AD_PKTTYPE:
 			ctx->flags |= SEEN_SKB;