nfp: flower: fix pre_tun mask id allocation

pre_tun_rule flows does not follow the usual add-flow path, instead
they are used to update the pre_tun table on the firmware. This means
that if the mask-id gets allocated here the firmware will never see the
"NFP_FL_META_FLAG_MANAGE_MASK" flag for the specific mask id, which
triggers the allocation on the firmware side. This leads to the firmware
mask being corrupted and causing all sorts of strange behaviour.

Fixes: f12725d9 ("nfp: flower: offload pre-tunnel rules")
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/metadata.c

@@ -327,8 +327,14 @@ int nfp_compile_flow_metadata(struct nfp_app *app,
 		goto err_free_ctx_entry;
 	}
 
+	/* Do net allocate a mask-id for pre_tun_rules. These flows are used to
+	 * configure the pre_tun table and are never actually send to the
+	 * firmware as an add-flow message. This causes the mask-id allocation
+	 * on the firmware to get out of sync if allocated here.
+	 */
 	new_mask_id = 0;
-	if (!nfp_check_mask_add(app, nfp_flow->mask_data,
+	if (!nfp_flow->pre_tun_rule.dev &&
+	    !nfp_check_mask_add(app, nfp_flow->mask_data,
 				nfp_flow->meta.mask_len,
 				&nfp_flow->meta.flags, &new_mask_id)) {
 		NL_SET_ERR_MSG_MOD(extack, "invalid entry: cannot allocate a new mask id");
@@ -359,7 +365,8 @@ int nfp_compile_flow_metadata(struct nfp_app *app,
 			goto err_remove_mask;
 		}
 
-		if (!nfp_check_mask_remove(app, nfp_flow->mask_data,
+		if (!nfp_flow->pre_tun_rule.dev &&
+		    !nfp_check_mask_remove(app, nfp_flow->mask_data,
 					   nfp_flow->meta.mask_len,
 					   NULL, &new_mask_id)) {
 			NL_SET_ERR_MSG_MOD(extack, "invalid entry: cannot release mask id");
@@ -374,8 +381,10 @@ int nfp_compile_flow_metadata(struct nfp_app *app,
 	return 0;
 
 err_remove_mask:
-	nfp_check_mask_remove(app, nfp_flow->mask_data, nfp_flow->meta.mask_len,
-			      NULL, &new_mask_id);
+	if (!nfp_flow->pre_tun_rule.dev)
+		nfp_check_mask_remove(app, nfp_flow->mask_data,
+				      nfp_flow->meta.mask_len,
+				      NULL, &new_mask_id);
 err_remove_rhash:
 	WARN_ON_ONCE(rhashtable_remove_fast(&priv->stats_ctx_table,
 					    &ctx_entry->ht_node,
@@ -406,9 +415,10 @@ int nfp_modify_flow_metadata(struct nfp_app *app,
 
 	__nfp_modify_flow_metadata(priv, nfp_flow);
 
-	nfp_check_mask_remove(app, nfp_flow->mask_data,
-			      nfp_flow->meta.mask_len, &nfp_flow->meta.flags,
-			      &new_mask_id);
+	if (!nfp_flow->pre_tun_rule.dev)
+		nfp_check_mask_remove(app, nfp_flow->mask_data,
+				      nfp_flow->meta.mask_len, &nfp_flow->meta.flags,
+				      &new_mask_id);
 
 	/* Update flow payload with mask ids. */
 	nfp_flow->unmasked_data[NFP_FL_MASK_ID_LOCATION] = new_mask_id;