[PATCH 06/38] mlx5: Convert counters_idr to XArray

[Matthew Wilcox <willy@infradead.org>]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

This IDR wasn't using the allocation functionality, so convert it to a
plain XArray.  I also suspect it could be used to replace the list_head
'counters', but I'm not willing to do that work right now.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 .../ethernet/mellanox/mlx5/core/fs_counters.c | 31 +++++--------------
 include/linux/mlx5/driver.h                   |  3 +-
 2 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
index 1804cf3c3814..5ee20d285c5e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
@@ -108,18 +108,14 @@ static struct list_head *mlx5_fc_counters_lookup_next(struct mlx5_core_dev *dev,
 						      u32 id)
 {
 	struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats;
-	unsigned long next_id = (unsigned long)id + 1;
 	struct mlx5_fc *counter;
-	unsigned long tmp;
+	unsigned long next_id;
 
-	rcu_read_lock();
-	/* skip counters that are in idr, but not yet in counters list */
-	idr_for_each_entry_continue_ul(&fc_stats->counters_idr,
-				       counter, tmp, next_id) {
+	/* skip counters that are not yet in counters list */
+	xa_for_each_start(&fc_stats->counters_xa, next_id, counter, id + 1) {
 		if (!list_empty(&counter->list))
 			break;
 	}
-	rcu_read_unlock();
 
 	return counter ? &counter->list : &fc_stats->counters;
 }
@@ -139,9 +135,7 @@ static void mlx5_fc_stats_remove(struct mlx5_core_dev *dev,
 
 	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);
+	WARN_ON(!xa_erase(&fc_stats->counters_xa, counter->id));
 }
 
 static int get_max_bulk_query_len(struct mlx5_core_dev *dev)
@@ -309,20 +303,12 @@ struct mlx5_fc *mlx5_fc_create(struct mlx5_core_dev *dev, bool aging)
 	counter->aging = aging;
 
 	if (aging) {
-		u32 id = counter->id;
-
 		counter->cache.lastuse = jiffies;
 		counter->lastbytes = counter->cache.bytes;
 		counter->lastpackets = counter->cache.packets;
 
-		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();
+		err = xa_insert(&fc_stats->counters_xa, counter->id, counter,
+				GFP_KERNEL);
 		if (err)
 			goto err_out_alloc;
 
@@ -368,8 +354,7 @@ int mlx5_init_fc_stats(struct mlx5_core_dev *dev)
 	int max_bulk_len;
 	int max_out_len;
 
-	spin_lock_init(&fc_stats->counters_idr_lock);
-	idr_init(&fc_stats->counters_idr);
+	xa_init(&fc_stats->counters_xa);
 	INIT_LIST_HEAD(&fc_stats->counters);
 	init_llist_head(&fc_stats->addlist);
 	init_llist_head(&fc_stats->dellist);
@@ -409,7 +394,7 @@ void mlx5_cleanup_fc_stats(struct mlx5_core_dev *dev)
 
 	kfree(fc_stats->bulk_query_out);
 
-	idr_destroy(&fc_stats->counters_idr);
+	xa_destroy(&fc_stats->counters_xa);
 
 	tmplist = llist_del_all(&fc_stats->addlist);
 	llist_for_each_entry_safe(counter, tmp, tmplist, addlist)
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index ba8f59b11920..b8b66cdb8357 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -477,8 +477,7 @@ struct mlx5_fc_pool {
 };
 
 struct mlx5_fc_stats {
-	spinlock_t counters_idr_lock; /* protects counters_idr */
-	struct idr counters_idr;
+	struct xarray counters_xa;
 	struct list_head counters;
 	struct llist_head addlist;
 	struct llist_head dellist;
-- 
2.23.0.rc1