1 files changed, 112 insertions, 89 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
index 58af6be13dfa..32accd6b041b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
@@ -52,11 +52,13 @@
  * access to counter list:
  * - create (user context)
  *   - mlx5_fc_create() only adds to an addlist to be used by
- *     mlx5_fc_stats_query_work(). addlist is protected by a spinlock.
+ *     mlx5_fc_stats_query_work(). addlist is a lockless single linked list
+ *     that doesn't require any additional synchronization when adding single
+ *     node.
  *   - spawn thread to do the actual destroy
  *
  * - destroy (user context)
- *   - mark a counter as deleted
+ *   - add a counter to lockless dellist
  *   - spawn thread to do the actual del
  *
  * - dump (user context)
@@ -71,36 +73,55 @@
  *   elapsed, the thread will actually query the hardware.
  */
 
-static void mlx5_fc_stats_insert(struct rb_root *root, struct mlx5_fc *counter)
+static struct list_head *mlx5_fc_counters_lookup_next(struct mlx5_core_dev *dev,
+						      u32 id)
 {
-	struct rb_node **new = &root->rb_node;
-	struct rb_node *parent = NULL;
-
-	while (*new) {
-		struct mlx5_fc *this = rb_entry(*new, struct mlx5_fc, node);
-		int result = counter->id - this->id;
-
-		parent = *new;
-		if (result < 0)
-			new = &((*new)->rb_left);
-		else
-			new = &((*new)->rb_right);
-	}
+	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
+	unsigned long next_id = (unsigned long)id + 1;
+	struct mlx5_fc *counter;
+
+	rcu_read_lock();
+	/* skip counters that are in idr, but not yet in counters list */
+	while ((counter = idr_get_next_ul(&fc_stats->counters_idr,
+					  &next_id)) != NULL &&
+	       list_empty(&counter->list))
+		next_id++;
+	rcu_read_unlock();
+
+	return counter ? &counter->list : &fc_stats->counters;
+}
+
+static void mlx5_fc_stats_insert(struct mlx5_core_dev *dev,
+				 struct mlx5_fc *counter)
+{
+	struct list_head *next = mlx5_fc_counters_lookup_next(dev, counter->id);
+
+	list_add_tail(&counter->list, next);
+}
+
+static void mlx5_fc_stats_remove(struct mlx5_core_dev *dev,
+				 struct mlx5_fc *counter)
+{
+	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
 
-	/* Add new node and rebalance tree. */
-	rb_link_node(&counter->node, parent, new);
-	rb_insert_color(&counter->node, root);
+	list_del(&counter->list);
+
+	spin_lock(&fc_stats->counters_idr_lock);
+	WARN_ON(!idr_remove(&fc_stats->counters_idr, counter->id));
+	spin_unlock(&fc_stats->counters_idr_lock);
 }
 
-/* The function returns the last node that was queried so the caller
+/* The function returns the last counter that was queried so the caller
  * function can continue calling it till all counters are queried.
  */
-static struct rb_node *mlx5_fc_stats_query(struct mlx5_core_dev *dev,
+static struct mlx5_fc *mlx5_fc_stats_query(struct mlx5_core_dev *dev,
 					   struct mlx5_fc *first,
 					   u32 last_id)
 {
+	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
+	struct mlx5_fc *counter = NULL;
 	struct mlx5_cmd_fc_bulk *b;
-	struct rb_node *node = NULL;
+	bool more = false;
 	u32 afirst_id;
 	int num;
 	int err;
@@ -130,14 +151,16 @@ static struct rb_node *mlx5_fc_stats_query(struct mlx5_core_dev *dev,
 		goto out;
 	}
 
-	for (node = &first->node; node; node = rb_next(node)) {
-		struct mlx5_fc *counter = rb_entry(node, struct mlx5_fc, node);
+	counter = first;
+	list_for_each_entry_from(counter, &fc_stats->counters, list) {
 		struct mlx5_fc_cache *c = &counter->cache;
 		u64 packets;
 		u64 bytes;
 
-		if (counter->id > last_id)
+		if (counter->id > last_id) {
+			more = true;
 			break;
+		}
 
 		mlx5_cmd_fc_bulk_get(dev, b,
 				     counter->id, &packets, &bytes);
@@ -153,7 +176,14 @@ static struct rb_node *mlx5_fc_stats_query(struct mlx5_core_dev *dev,
 out:
 	mlx5_cmd_fc_bulk_free(b);
 
-	return node;
+	return more ? counter : NULL;
+}
+
+static void mlx5_free_fc(struct mlx5_core_dev *dev,
+			 struct mlx5_fc *counter)
+{
+	mlx5_cmd_fc_free(dev, counter->id);
+	kfree(counter);
 }
 
 static void mlx5_fc_stats_work(struct work_struct *work)
@@ -161,52 +191,36 @@ static void mlx5_fc_stats_work(struct work_struct *work)
 	struct mlx5_core_dev *dev = container_of(work, struct mlx5_core_dev,
 						 priv.fc_stats.work.work);
 	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
+	/* Take dellist first to ensure that counters cannot be deleted before
+	 * they are inserted.
+	 */
+	struct llist_node *dellist = llist_del_all(&fc_stats->dellist);
+	struct llist_node *addlist = llist_del_all(&fc_stats->addlist);
+	struct mlx5_fc *counter = NULL, *last = NULL, *tmp;
 	unsigned long now = jiffies;
-	struct mlx5_fc *counter = NULL;
-	struct mlx5_fc *last = NULL;
-	struct rb_node *node;
-	LIST_HEAD(tmplist);
 
-	spin_lock(&fc_stats->addlist_lock);
-
-	list_splice_tail_init(&fc_stats->addlist, &tmplist);
-
-	if (!list_empty(&tmplist) || !RB_EMPTY_ROOT(&fc_stats->counters))
+	if (addlist || !list_empty(&fc_stats->counters))
 		queue_delayed_work(fc_stats->wq, &fc_stats->work,
 				   fc_stats->sampling_interval);
 
-	spin_unlock(&fc_stats->addlist_lock);
-
-	list_for_each_entry(counter, &tmplist, list)
-		mlx5_fc_stats_insert(&fc_stats->counters, counter);
+	llist_for_each_entry(counter, addlist, addlist)
+		mlx5_fc_stats_insert(dev, counter);
 
-	node = rb_first(&fc_stats->counters);
-	while (node) {
-		counter = rb_entry(node, struct mlx5_fc, node);
+	llist_for_each_entry_safe(counter, tmp, dellist, dellist) {
+		mlx5_fc_stats_remove(dev, counter);
 
-		node = rb_next(node);
-
-		if (counter->deleted) {
-			rb_erase(&counter->node, &fc_stats->counters);
-
-			mlx5_cmd_fc_free(dev, counter->id);
-
-			kfree(counter);
-			continue;
-		}
-
-		last = counter;
+		mlx5_free_fc(dev, counter);
 	}
 
-	if (time_before(now, fc_stats->next_query) || !last)
+	if (time_before(now, fc_stats->next_query) ||
+	    list_empty(&fc_stats->counters))
 		return;
+	last = list_last_entry(&fc_stats->counters, struct mlx5_fc, list);
 
-	node = rb_first(&fc_stats->counters);
-	while (node) {
-		counter = rb_entry(node, struct mlx5_fc, node);
-
-		node = mlx5_fc_stats_query(dev, counter, last->id);
-	}
+	counter = list_first_entry(&fc_stats->counters, struct mlx5_fc,
+				   list);
+	while (counter)
+		counter = mlx5_fc_stats_query(dev, counter, last->id);
 
 	fc_stats->next_query = now + fc_stats->sampling_interval;
 }
@@ -220,24 +234,38 @@ struct mlx5_fc *mlx5_fc_create(struct mlx5_core_dev *dev, bool aging)
 	counter = kzalloc(sizeof(*counter), GFP_KERNEL);
 	if (!counter)
 		return ERR_PTR(-ENOMEM);
+	INIT_LIST_HEAD(&counter->list);
 
 	err = mlx5_cmd_fc_alloc(dev, &counter->id);
 	if (err)
 		goto err_out;
 
 	if (aging) {
+		u32 id = counter->id;
+
 		counter->cache.lastuse = jiffies;
 		counter->aging = true;
 
-		spin_lock(&fc_stats->addlist_lock);
-		list_add(&counter->list, &fc_stats->addlist);
-		spin_unlock(&fc_stats->addlist_lock);
+		idr_preload(GFP_KERNEL);
+		spin_lock(&fc_stats->counters_idr_lock);
+
+		err = idr_alloc_u32(&fc_stats->counters_idr, counter, &id, id,
+				    GFP_NOWAIT);
+
+		spin_unlock(&fc_stats->counters_idr_lock);
+		idr_preload_end();
+		if (err)
+			goto err_out_alloc;
+
+		llist_add(&counter->addlist, &fc_stats->addlist);
 
 		mod_delayed_work(fc_stats->wq, &fc_stats->work, 0);
 	}
 
 	return counter;
 
+err_out_alloc:
+	mlx5_cmd_fc_free(dev, counter->id);
 err_out:
 	kfree(counter);
 
@@ -245,6 +273,12 @@ err_out:
 }
 EXPORT_SYMBOL(mlx5_fc_create);
 
+u32 mlx5_fc_id(struct mlx5_fc *counter)
+{
+	return counter->id;
+}
+EXPORT_SYMBOL(mlx5_fc_id);
+
 void mlx5_fc_destroy(struct mlx5_core_dev *dev, struct mlx5_fc *counter)
 {
 	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
@@ -253,13 +287,12 @@ void mlx5_fc_destroy(struct mlx5_core_dev *dev, struct mlx5_fc *counter)
 		return;
 
 	if (counter->aging) {
-		counter->deleted = true;
+		llist_add(&counter->dellist, &fc_stats->dellist);
 		mod_delayed_work(fc_stats->wq, &fc_stats->work, 0);
 		return;
 	}
 
-	mlx5_cmd_fc_free(dev, counter->id);
-	kfree(counter);
+	mlx5_free_fc(dev, counter);
 }
 EXPORT_SYMBOL(mlx5_fc_destroy);
 
@@ -267,9 +300,11 @@ int mlx5_init_fc_stats(struct mlx5_core_dev *dev)
 {
 	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
 
-	fc_stats->counters = RB_ROOT;
-	INIT_LIST_HEAD(&fc_stats->addlist);
-	spin_lock_init(&fc_stats->addlist_lock);
+	spin_lock_init(&fc_stats->counters_idr_lock);
+	idr_init(&fc_stats->counters_idr);
+	INIT_LIST_HEAD(&fc_stats->counters);
+	init_llist_head(&fc_stats->addlist);
+	init_llist_head(&fc_stats->dellist);
 
 	fc_stats->wq = create_singlethread_workqueue("mlx5_fc");
 	if (!fc_stats->wq)
@@ -284,34 +319,22 @@ int mlx5_init_fc_stats(struct mlx5_core_dev *dev)
 void mlx5_cleanup_fc_stats(struct mlx5_core_dev *dev)
 {
 	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
+	struct llist_node *tmplist;
 	struct mlx5_fc *counter;
 	struct mlx5_fc *tmp;
-	struct rb_node *node;
 
 	cancel_delayed_work_sync(&dev->priv.fc_stats.work);
 	destroy_workqueue(dev->priv.fc_stats.wq);
 	dev->priv.fc_stats.wq = NULL;
 
-	list_for_each_entry_safe(counter, tmp, &fc_stats->addlist, list) {
-		list_del(&counter->list);
-
-		mlx5_cmd_fc_free(dev, counter->id);
+	idr_destroy(&fc_stats->counters_idr);
 
-		kfree(counter);
-	}
-
-	node = rb_first(&fc_stats->counters);
-	while (node) {
-		counter = rb_entry(node, struct mlx5_fc, node);
-
-		node = rb_next(node);
+	tmplist = llist_del_all(&fc_stats->addlist);
+	llist_for_each_entry_safe(counter, tmp, tmplist, addlist)
+		mlx5_free_fc(dev, counter);
 
-		rb_erase(&counter->node, &fc_stats->counters);
-
-		mlx5_cmd_fc_free(dev, counter->id);
-
-		kfree(counter);
-	}
+	list_for_each_entry_safe(counter, tmp, &fc_stats->counters, list)
+		mlx5_free_fc(dev, counter);
 }
 
 int mlx5_fc_query(struct mlx5_core_dev *dev, struct mlx5_fc *counter,