net/mlx5: Support multiple updates of steering rules in parallel

Most of the time spent on adding new flow steering rule
is executing the firmware command.
The most common action is adding a new flow steering entry.
In order to enhance the update rate we parallelize the
commands by doing the following:

1) Replace the mutex lock with readers-writers semaphore and take
the write lock only when necessary (e.g. allocating a new flow
table entry index or adding a node to the parent's children list).
When we try to find a suitable child in the parent's children list
(e.g. search for flow group with the same match_criteria of the rule)
then we only take the read lock.

2) Add versioning mechanism - each steering entity (FT, FG, FTE, DST)
will have an incremental version. The version is increased when the
entity is changed (e.g. when a new FTE was added to FG - the FG's
version is increased).
Versioning is used in order to determine if the last traverse of an
entity's children is valid or a rescan under write lock is required.

This support improves the insertion rate of steering rules
from ~5k/sec to ~40k/sec.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/fs_core.c

@@ -168,10 +168,16 @@ static const struct rhashtable_params rhash_fg = {
 
 };
 
-static void del_rule(struct fs_node *node);
-static void del_flow_table(struct fs_node *node);
-static void del_flow_group(struct fs_node *node);
-static void del_fte(struct fs_node *node);
+static void del_hw_flow_table(struct fs_node *node);
+static void del_hw_flow_group(struct fs_node *node);
+static void del_hw_fte(struct fs_node *node);
+static void del_sw_flow_table(struct fs_node *node);
+static void del_sw_flow_group(struct fs_node *node);
+static void del_sw_fte(struct fs_node *node);
+/* Delete rule (destination) is special case that 
+ * requires to lock the FTE for all the deletion process.
+ */
+static void del_sw_hw_rule(struct fs_node *node);
 static bool mlx5_flow_dests_cmp(struct mlx5_flow_destination *d1,
 				struct mlx5_flow_destination *d2);
 static struct mlx5_flow_rule *
@@ -179,13 +185,15 @@ find_flow_rule(struct fs_fte *fte,
 	       struct mlx5_flow_destination *dest);
 
 static void tree_init_node(struct fs_node *node,
-			   void (*remove_func)(struct fs_node *))
+			   void (*del_hw_func)(struct fs_node *),
+			   void (*del_sw_func)(struct fs_node *))
 {
 	atomic_set(&node->refcount, 1);
 	INIT_LIST_HEAD(&node->list);
 	INIT_LIST_HEAD(&node->children);
 	init_rwsem(&node->lock);
-	node->remove_func = remove_func;
+	node->del_hw_func = del_hw_func;
+	node->del_sw_func = del_sw_func;
 	node->active = false;
 }
 
@@ -202,50 +210,69 @@ static void tree_add_node(struct fs_node *node, struct fs_node *parent)
 		node->root = parent->root;
 }
 
-static void tree_get_node(struct fs_node *node)
+static int tree_get_node(struct fs_node *node)
 {
-	atomic_inc(&node->refcount);
+	return atomic_add_unless(&node->refcount, 1, 0);
 }
 
-static void nested_lock_ref_node(struct fs_node *node,
-				 enum fs_i_lock_class class)
+static void nested_down_read_ref_node(struct fs_node *node,
+				      enum fs_i_lock_class class)
 {
 	if (node) {
-		down_write_nested(&node->lock, class);
+		down_read_nested(&node->lock, class);
 		atomic_inc(&node->refcount);
 	}
 }
 
-static void lock_ref_node(struct fs_node *node)
+static void nested_down_write_ref_node(struct fs_node *node,
+				       enum fs_i_lock_class class)
 {
 	if (node) {
-		down_write(&node->lock);
+		down_write_nested(&node->lock, class);
 		atomic_inc(&node->refcount);
 	}
 }
 
-static void unlock_ref_node(struct fs_node *node)
+static void down_write_ref_node(struct fs_node *node)
 {
 	if (node) {
-		atomic_dec(&node->refcount);
-		up_write(&node->lock);
+		down_write(&node->lock);
+		atomic_inc(&node->refcount);
 	}
 }
 
+static void up_read_ref_node(struct fs_node *node)
+{
+	atomic_dec(&node->refcount);
+	up_read(&node->lock);
+}
+
+static void up_write_ref_node(struct fs_node *node)
+{
+	atomic_dec(&node->refcount);
+	up_write(&node->lock);
+}
+
 static void tree_put_node(struct fs_node *node)
 {
 	struct fs_node *parent_node = node->parent;
 
-	lock_ref_node(parent_node);
 	if (atomic_dec_and_test(&node->refcount)) {
-		if (parent_node)
+		if (node->del_hw_func)
+			node->del_hw_func(node);
+		if (parent_node) {
+			/* Only root namespace doesn't have parent and we just
+			 * need to free its node.
+			 */
+			down_write_ref_node(parent_node);
 			list_del_init(&node->list);
-		if (node->remove_func)
-			node->remove_func(node);
+			if (node->del_sw_func)
+				node->del_sw_func(node);
+			up_write_ref_node(parent_node);
+		}
 		kfree(node);
 		node = NULL;
 	}
-	unlock_ref_node(parent_node);
 	if (!node && parent_node)
 		tree_put_node(parent_node);
 }
@@ -371,11 +398,10 @@ static inline struct mlx5_core_dev *get_dev(struct fs_node *node)
 	return NULL;
 }
 
-static void del_flow_table(struct fs_node *node)
+static void del_hw_flow_table(struct fs_node *node)
 {
 	struct mlx5_flow_table *ft;
 	struct mlx5_core_dev *dev;
-	struct fs_prio *prio;
 	int err;
 
 	fs_get_obj(ft, node);
@@ -386,12 +412,21 @@ static void del_flow_table(struct fs_node *node)
 		if (err)
 			mlx5_core_warn(dev, "flow steering can't destroy ft\n");
 	}
+}
+
+static void del_sw_flow_table(struct fs_node *node)
+{
+	struct mlx5_flow_table *ft;
+	struct fs_prio *prio;
+
+	fs_get_obj(ft, node);
+
 	rhltable_destroy(&ft->fgs_hash);
 	fs_get_obj(prio, ft->node.parent);
 	prio->num_ft--;
 }
 
-static void del_rule(struct fs_node *node)
+static void del_sw_hw_rule(struct fs_node *node)
 {
 	struct mlx5_flow_rule *rule;
 	struct mlx5_flow_table *ft;
@@ -407,7 +442,6 @@ static void del_rule(struct fs_node *node)
 	fs_get_obj(fg, fte->node.parent);
 	fs_get_obj(ft, fg->node.parent);
 	trace_mlx5_fs_del_rule(rule);
-	list_del(&rule->node.list);
 	if (rule->sw_action == MLX5_FLOW_CONTEXT_ACTION_FWD_NEXT_PRIO) {
 		mutex_lock(&rule->dest_attr.ft->lock);
 		list_del(&rule->next_ft);
@@ -437,7 +471,7 @@ out:
 	}
 }
 
-static void del_fte(struct fs_node *node)
+static void del_hw_fte(struct fs_node *node)
 {
 	struct mlx5_flow_table *ft;
 	struct mlx5_flow_group *fg;
@@ -448,8 +482,8 @@ static void del_fte(struct fs_node *node)
 	fs_get_obj(fte, node);
 	fs_get_obj(fg, fte->node.parent);
 	fs_get_obj(ft, fg->node.parent);
-	trace_mlx5_fs_del_fte(fte);
 
+	trace_mlx5_fs_del_fte(fte);
 	dev = get_dev(&ft->node);
 	if (node->active) {
 		err = mlx5_cmd_delete_fte(dev, ft,
@@ -459,6 +493,16 @@ static void del_fte(struct fs_node *node)
 				       "flow steering can't delete fte in index %d of flow group id %d\n",
 				       fte->index, fg->id);
 	}
+}
+
+static void del_sw_fte(struct fs_node *node)
+{
+	struct mlx5_flow_group *fg;
+	struct fs_fte *fte;
+	int err;
+
+	fs_get_obj(fte, node);
+	fs_get_obj(fg, fte->node.parent);
 
 	err = rhashtable_remove_fast(&fg->ftes_hash,
 				     &fte->hash,
@@ -467,30 +511,39 @@ static void del_fte(struct fs_node *node)
 	ida_simple_remove(&fg->fte_allocator, fte->index - fg->start_index);
 }
 
-static void del_flow_group(struct fs_node *node)
+static void del_hw_flow_group(struct fs_node *node)
 {
 	struct mlx5_flow_group *fg;
 	struct mlx5_flow_table *ft;
 	struct mlx5_core_dev *dev;
-	int err;
 
 	fs_get_obj(fg, node);
 	fs_get_obj(ft, fg->node.parent);
 	dev = get_dev(&ft->node);
 	trace_mlx5_fs_del_fg(fg);
 
-	if (ft->autogroup.active)
-		ft->autogroup.num_groups--;
+	if (fg->node.active && mlx5_cmd_destroy_flow_group(dev, ft, fg->id))
+		mlx5_core_warn(dev, "flow steering can't destroy fg %d of ft %d\n",
+			       fg->id, ft->id);
+}
+
+static void del_sw_flow_group(struct fs_node *node)
+{
+	struct mlx5_flow_group *fg;
+	struct mlx5_flow_table *ft;
+	int err;
+
+	fs_get_obj(fg, node);
+	fs_get_obj(ft, fg->node.parent);
 
 	rhashtable_destroy(&fg->ftes_hash);
 	ida_destroy(&fg->fte_allocator);
+	if (ft->autogroup.active)
+		ft->autogroup.num_groups--;
 	err = rhltable_remove(&ft->fgs_hash,
 			      &fg->hash,
 			      rhash_fg);
 	WARN_ON(err);
-	if (fg->node.active && mlx5_cmd_destroy_flow_group(dev, ft, fg->id))
-		mlx5_core_warn(dev, "flow steering can't destroy fg %d of ft %d\n",
-			       fg->id, ft->id);
 }
 
 static struct fs_fte *alloc_fte(struct mlx5_flow_act *flow_act,
@@ -540,7 +593,7 @@ static struct fs_fte *alloc_insert_fte(struct mlx5_flow_group *fg,
 	if (ret)
 		goto err_free;
 
-	tree_init_node(&fte->node, del_fte);
+	tree_init_node(&fte->node, del_hw_fte, del_sw_fte);
 	tree_add_node(&fte->node, &fg->node);
 	list_add_tail(&fte->node.list, &fg->node.children);
 
@@ -611,10 +664,11 @@ static struct mlx5_flow_group *alloc_insert_flow_group(struct mlx5_flow_table *f
 		return ERR_PTR(ret);
 	}
 
-	tree_init_node(&fg->node, del_flow_group);
+	tree_init_node(&fg->node, del_hw_flow_group, del_sw_flow_group);
 	tree_add_node(&fg->node, &ft->node);
 	/* Add node to group list */
 	list_add(&fg->node.list, prev);
+	atomic_inc(&ft->node.version);
 
 	return fg;
 }
@@ -794,7 +848,7 @@ static int _mlx5_modify_rule_destination(struct mlx5_flow_rule *rule,
 	fs_get_obj(fte, rule->node.parent);
 	if (!(fte->action & MLX5_FLOW_CONTEXT_ACTION_FWD_DEST))
 		return -EINVAL;
-	lock_ref_node(&fte->node);
+	down_write_ref_node(&fte->node);
 	fs_get_obj(fg, fte->node.parent);
 	fs_get_obj(ft, fg->node.parent);
 
@@ -803,7 +857,7 @@ static int _mlx5_modify_rule_destination(struct mlx5_flow_rule *rule,
 				  ft, fg->id,
 				  modify_mask,
 				  fte);
-	unlock_ref_node(&fte->node);
+	up_write_ref_node(&fte->node);
 
 	return err;
 }
@@ -940,7 +994,7 @@ static struct mlx5_flow_table *__mlx5_create_flow_table(struct mlx5_flow_namespa
 		goto unlock_root;
 	}
 
-	tree_init_node(&ft->node, del_flow_table);
+	tree_init_node(&ft->node, del_hw_flow_table, del_sw_flow_table);
 	log_table_sz = ft->max_fte ? ilog2(ft->max_fte) : 0;
 	next_ft = find_next_chained_ft(fs_prio);
 	err = mlx5_cmd_create_flow_table(root->dev, ft->vport, ft->op_mod, ft->type,
@@ -953,11 +1007,11 @@ static struct mlx5_flow_table *__mlx5_create_flow_table(struct mlx5_flow_namespa
 	if (err)
 		goto destroy_ft;
 	ft->node.active = true;
-	lock_ref_node(&fs_prio->node);
+	down_write_ref_node(&fs_prio->node);
 	tree_add_node(&ft->node, &fs_prio->node);
 	list_add_flow_table(ft, fs_prio);
 	fs_prio->num_ft++;
-	unlock_ref_node(&fs_prio->node);
+	up_write_ref_node(&fs_prio->node);
 	mutex_unlock(&root->chain_lock);
 	return ft;
 destroy_ft:
@@ -1052,11 +1106,11 @@ struct mlx5_flow_group *mlx5_create_flow_group(struct mlx5_flow_table *ft,
 	if (ft->autogroup.active)
 		return ERR_PTR(-EPERM);
 
-	lock_ref_node(&ft->node);
+	down_write_ref_node(&ft->node);
 	fg = alloc_insert_flow_group(ft, match_criteria_enable, match_criteria,
 				     start_index, end_index,
 				     ft->node.children.prev);
-	unlock_ref_node(&ft->node);
+	up_write_ref_node(&ft->node);
 	if (IS_ERR(fg))
 		return fg;
 
@@ -1151,7 +1205,7 @@ create_flow_handle(struct fs_fte *fte,
 		/* Add dest to dests list- we need flow tables to be in the
 		 * end of the list for forward to next prio rules.
 		 */
-		tree_init_node(&rule->node, del_rule);
+		tree_init_node(&rule->node, NULL, del_sw_hw_rule);
 		if (dest &&
 		    dest[i].type != MLX5_FLOW_DESTINATION_TYPE_FLOW_TABLE)
 			list_add(&rule->node.list, &fte->node.children);
@@ -1209,6 +1263,7 @@ add_rule_fte(struct fs_fte *fte,
 
 	fte->node.active = true;
 	fte->status |= FS_FTE_STATUS_EXISTING;
+	atomic_inc(&fte->node.version);
 
 out:
 	return handle;
@@ -1369,54 +1424,30 @@ static struct mlx5_flow_handle *add_rule_fg(struct mlx5_flow_group *fg,
 					    struct fs_fte *fte)
 {
 	struct mlx5_flow_handle *handle;
-	struct mlx5_flow_table *ft;
+	int old_action;
 	int i;
+	int ret;
 
-	if (fte) {
-		int old_action;
-		int ret;
-
-		nested_lock_ref_node(&fte->node, FS_LOCK_CHILD);
-		ret = check_conflicting_ftes(fte, flow_act);
-		if (ret) {
-			handle = ERR_PTR(ret);
-			goto unlock_fte;
-		}
-
-		old_action = fte->action;
-		fte->action |= flow_act->action;
-		handle = add_rule_fte(fte, fg, dest, dest_num,
-				      old_action != flow_act->action);
-		if (IS_ERR(handle)) {
-			fte->action = old_action;
-			goto unlock_fte;
-		} else {
-			trace_mlx5_fs_set_fte(fte, false);
-			goto add_rules;
-		}
-	}
-	fs_get_obj(ft, fg->node.parent);
+	ret = check_conflicting_ftes(fte, flow_act);
+	if (ret)
+		return ERR_PTR(ret);
 
-	fte = alloc_insert_fte(fg, match_value, flow_act);
-	if (IS_ERR(fte))
-		return (void *)fte;
-	nested_lock_ref_node(&fte->node, FS_LOCK_CHILD);
-	handle = add_rule_fte(fte, fg, dest, dest_num, false);
+	old_action = fte->action;
+	fte->action |= flow_act->action;
+	handle = add_rule_fte(fte, fg, dest, dest_num,
+			      old_action != flow_act->action);
 	if (IS_ERR(handle)) {
-		unlock_ref_node(&fte->node);
-		tree_put_node(&fte->node);
+		fte->action = old_action;
 		return handle;
 	}
+	trace_mlx5_fs_set_fte(fte, false);
 
-add_rules:
 	for (i = 0; i < handle->num_rules; i++) {
 		if (atomic_read(&handle->rule[i]->node.refcount) == 1) {
 			tree_add_node(&handle->rule[i]->node, &fte->node);
 			trace_mlx5_fs_add_rule(handle->rule[i]);
 		}
 	}
-unlock_fte:
-	unlock_ref_node(&fte->node);
 	return handle;
 }
 
@@ -1480,8 +1511,10 @@ static void free_match_list(struct match_list_head *head)
 		struct match_list *iter, *match_tmp;
 
 		list_del(&head->first.list);
+		tree_put_node(&head->first.g->node);
 		list_for_each_entry_safe(iter, match_tmp, &head->list,
 					 list) {
+			tree_put_node(&iter->g->node);
 			list_del(&iter->list);
 			kfree(iter);
 		}
@@ -1505,6 +1538,8 @@ static int build_match_list(struct match_list_head *match_head,
 		struct match_list *curr_match;
 
 		if (likely(list_empty(&match_head->list))) {
+			if (!tree_get_node(&g->node))
+				continue;
 			match_head->first.g = g;
 			list_add_tail(&match_head->first.list,
 				      &match_head->list);
@@ -1517,6 +1552,10 @@ static int build_match_list(struct match_list_head *match_head,
 			err = -ENOMEM;
 			goto out;
 		}
+		if (!tree_get_node(&g->node)) {
+			kfree(curr_match);
+			continue;
+		}
 		curr_match->g = g;
 		list_add_tail(&curr_match->list, &match_head->list);
 	}
@@ -1525,62 +1564,119 @@ out:
 	return err;
 }
 
+static u64 matched_fgs_get_version(struct list_head *match_head)
+{
+	struct match_list *iter;
+	u64 version = 0;
+
+	list_for_each_entry(iter, match_head, list)
+		version += (u64)atomic_read(&iter->g->node.version);
+	return version;
+}
+
 static struct mlx5_flow_handle *
 try_add_to_existing_fg(struct mlx5_flow_table *ft,
+		       struct list_head *match_head,
 		       struct mlx5_flow_spec *spec,
 		       struct mlx5_flow_act *flow_act,
 		       struct mlx5_flow_destination *dest,
-		       int dest_num)
+		       int dest_num,
+		       int ft_version)
 {
 	struct mlx5_flow_group *g;
 	struct mlx5_flow_handle *rule;
-	struct match_list_head match_head;
 	struct match_list *iter;
-	int err;
+	bool take_write = false;
+	struct fs_fte *fte;
+	u64  version;
 
-	/* Collect all fgs which has a matching match_criteria */
-	err = build_match_list(&match_head, ft, spec);
-	if (err)
-		return ERR_PTR(err);
+	list_for_each_entry(iter, match_head, list) {
+		nested_down_read_ref_node(&iter->g->node, FS_LOCK_PARENT);
+		ida_pre_get(&iter->g->fte_allocator, GFP_KERNEL);
+	}
 
+search_again_locked:
+	version = matched_fgs_get_version(match_head);
 	/* Try to find a fg that already contains a matching fte */
-	list_for_each_entry(iter, &match_head.list, list) {
-		struct fs_fte *fte;
+	list_for_each_entry(iter, match_head, list) {
+		struct fs_fte *fte_tmp;
 
 		g = iter->g;
-		nested_lock_ref_node(&g->node, FS_LOCK_PARENT);
-		fte = rhashtable_lookup_fast(&g->ftes_hash, spec->match_value,
-					     rhash_fte);
-		if (fte) {
-			rule = add_rule_fg(g, spec->match_value,
-					   flow_act, dest, dest_num, fte);
-			unlock_ref_node(&g->node);
-			goto free_list;
+		fte_tmp = rhashtable_lookup_fast(&g->ftes_hash, spec->match_value,
+						 rhash_fte);
+		if (!fte_tmp || !tree_get_node(&fte_tmp->node))
+			continue;
+
+		nested_down_write_ref_node(&fte_tmp->node, FS_LOCK_CHILD);
+		if (!take_write) {
+			list_for_each_entry(iter, match_head, list)
+				up_read_ref_node(&iter->g->node);
+		} else {
+			list_for_each_entry(iter, match_head, list)
+				up_write_ref_node(&iter->g->node);
 		}
-		unlock_ref_node(&g->node);
+
+		rule = add_rule_fg(g, spec->match_value,
+				   flow_act, dest, dest_num, fte_tmp);
+		up_write_ref_node(&fte_tmp->node);
+		tree_put_node(&fte_tmp->node);
+		return rule;
 	}
 
 	/* No group with matching fte found. Try to add a new fte to any
 	 * matching fg.
 	 */
-	list_for_each_entry(iter, &match_head.list, list) {
-		g = iter->g;
 
-		nested_lock_ref_node(&g->node, FS_LOCK_PARENT);
-		rule = add_rule_fg(g, spec->match_value,
-				   flow_act, dest, dest_num, NULL);
-		if (!IS_ERR(rule) || PTR_ERR(rule) != -ENOSPC) {
-			unlock_ref_node(&g->node);
-			goto free_list;
-		}
-		unlock_ref_node(&g->node);
+	if (!take_write) {
+		list_for_each_entry(iter, match_head, list)
+			up_read_ref_node(&iter->g->node);
+		list_for_each_entry(iter, match_head, list)
+			nested_down_write_ref_node(&iter->g->node,
+						   FS_LOCK_PARENT);
+		take_write = true;
 	}
 
-	rule = ERR_PTR(-ENOENT);
+	/* Check the ft version, for case that new flow group
+	 * was added while the fgs weren't locked
+	 */
+	if (atomic_read(&ft->node.version) != ft_version) {
+		rule = ERR_PTR(-EAGAIN);
+		goto out;
+	}
 
-free_list:
-	free_match_list(&match_head);
+	/* Check the fgs version, for case the new FTE with the
+	 * same values was added while the fgs weren't locked
+	 */
+	if (version != matched_fgs_get_version(match_head))
+		goto search_again_locked;
+
+	list_for_each_entry(iter, match_head, list) {
+		g = iter->g;
+
+		if (!g->node.active)
+			continue;
+		fte = alloc_insert_fte(g, spec->match_value, flow_act);
+		if (IS_ERR(fte)) {
+			if (PTR_ERR(fte) == -ENOSPC)
+				continue;
+			list_for_each_entry(iter, match_head, list)
+				up_write_ref_node(&iter->g->node);
+			return (void *)fte;
+		}
 
+		nested_down_write_ref_node(&fte->node, FS_LOCK_CHILD);
+		list_for_each_entry(iter, match_head, list)
+			up_write_ref_node(&iter->g->node);
+		rule = add_rule_fg(g, spec->match_value,
+				   flow_act, dest, dest_num, fte);
+		up_write_ref_node(&fte->node);
+		tree_put_node(&fte->node);
+		return rule;
+	}
+	rule = ERR_PTR(-ENOENT);
+out:
+	list_for_each_entry(iter, match_head, list)
+		up_write_ref_node(&iter->g->node);
 	return rule;
 }
 
@@ -1594,6 +1690,10 @@ _mlx5_add_flow_rules(struct mlx5_flow_table *ft,
 {
 	struct mlx5_flow_group *g;
 	struct mlx5_flow_handle *rule;
+	struct match_list_head match_head;
+	bool take_write = false;
+	struct fs_fte *fte;
+	int version;
 	int err;
 	int i;
 
@@ -1604,31 +1704,67 @@ _mlx5_add_flow_rules(struct mlx5_flow_table *ft,
 		if (!dest_is_valid(&dest[i], flow_act->action, ft))
 			return ERR_PTR(-EINVAL);
 	}
+	nested_down_read_ref_node(&ft->node, FS_LOCK_GRANDPARENT);
+search_again_locked:
+	version = atomic_read(&ft->node.version);
 
-	nested_lock_ref_node(&ft->node, FS_LOCK_GRANDPARENT);
-	rule = try_add_to_existing_fg(ft, spec, flow_act, dest, dest_num);
-	if (!IS_ERR(rule) || PTR_ERR(rule) != -ENOENT)
-		goto unlock;
+	/* Collect all fgs which has a matching match_criteria */
+	err = build_match_list(&match_head, ft, spec);
+	if (err)
+		return ERR_PTR(err);
+
+	if (!take_write)
+		up_read_ref_node(&ft->node);
+
+	rule = try_add_to_existing_fg(ft, &match_head.list, spec, flow_act, dest,
+				      dest_num, version);
+	free_match_list(&match_head);
+	if (!IS_ERR(rule) ||
+	    (PTR_ERR(rule) != -ENOENT && PTR_ERR(rule) != -EAGAIN))
+		return rule;
+
+	if (!take_write) {
+		nested_down_write_ref_node(&ft->node, FS_LOCK_GRANDPARENT);
+		take_write = true;
+	}
+
+	if (PTR_ERR(rule) == -EAGAIN ||
+	    version != atomic_read(&ft->node.version))
+		goto search_again_locked;
 
 	g = alloc_auto_flow_group(ft, spec);
 	if (IS_ERR(g)) {
 		rule = (void *)g;
-		goto unlock;
+		up_write_ref_node(&ft->node);
+		return rule;
 	}
 
+	nested_down_write_ref_node(&g->node, FS_LOCK_PARENT);
+	up_write_ref_node(&ft->node);
+
 	err = create_auto_flow_group(ft, g);
-	if (err) {
-		rule = ERR_PTR(err);
-		goto put_fg;
+	if (err)
+		goto err_release_fg;
+
+	fte = alloc_insert_fte(g, spec->match_value, flow_act);
+	if (IS_ERR(fte)) {
+		err = PTR_ERR(fte);
+		goto err_release_fg;
 	}
 
+	nested_down_write_ref_node(&fte->node, FS_LOCK_CHILD);
+	up_write_ref_node(&g->node);
 	rule = add_rule_fg(g, spec->match_value, flow_act, dest,
-			   dest_num, NULL);
-put_fg:
+			   dest_num, fte);
+	up_write_ref_node(&fte->node);
+	tree_put_node(&fte->node);
 	tree_put_node(&g->node);
-unlock:
-	unlock_ref_node(&ft->node);
 	return rule;
+
+err_release_fg:
+	up_write_ref_node(&g->node);
+	tree_put_node(&g->node);
+	return ERR_PTR(err);
 }
 
 static bool fwd_next_prio_supported(struct mlx5_flow_table *ft)
@@ -1869,7 +2005,7 @@ static struct fs_prio *fs_create_prio(struct mlx5_flow_namespace *ns,
 		return ERR_PTR(-ENOMEM);
 
 	fs_prio->node.type = FS_TYPE_PRIO;
-	tree_init_node(&fs_prio->node, NULL);
+	tree_init_node(&fs_prio->node, NULL, NULL);
 	tree_add_node(&fs_prio->node, &ns->node);
 	fs_prio->num_levels = num_levels;
 	fs_prio->prio = prio;
@@ -1895,7 +2031,7 @@ static struct mlx5_flow_namespace *fs_create_namespace(struct fs_prio *prio)
 		return ERR_PTR(-ENOMEM);
 
 	fs_init_namespace(ns);
-	tree_init_node(&ns->node, NULL);
+	tree_init_node(&ns->node, NULL, NULL);
 	tree_add_node(&ns->node, &prio->node);
 	list_add_tail(&ns->node.list, &prio->node.children);
 
@@ -2020,7 +2156,7 @@ static struct mlx5_flow_root_namespace *create_root_ns(struct mlx5_flow_steering
 	ns = &root_ns->ns;
 	fs_init_namespace(ns);
 	mutex_init(&root_ns->chain_lock);
-	tree_init_node(&ns->node, NULL);
+	tree_init_node(&ns->node, NULL, NULL);
 	tree_add_node(&ns->node, NULL);
 
 	return root_ns;

drivers/net/ethernet/mellanox/mlx5/core/fs_core.h

@@ -83,7 +83,9 @@ struct fs_node {
 	struct rw_semaphore	lock;
 	atomic_t		refcount;
 	bool			active;
-	void			(*remove_func)(struct fs_node *);
+	void			(*del_hw_func)(struct fs_node *);
+	void			(*del_sw_func)(struct fs_node *);
+	atomic_t		version;
 };
 
 struct mlx5_flow_rule {