[PATCH net-next 03/13] net/mlx5: LAG, allocate v2p_map dynamically

[Tariq Toukan <tariqt@nvidia.com>]

From: Shay Drory <shayd@nvidia.com>

v2p_map was a fixed array sized MLX5_MAX_PORTS *
MLX5_LAG_MAX_HASH_BUCKETS embedded in struct mlx5_lag. Turn it into a
pointer allocated in mlx5_lag_dev_alloc() once ldev->ports is known,
sized by the actual port count, and free it in mlx5_ldev_free(). The
ldev->ports / ldev->buckets initialization is moved up so the allocation
can use it.

The matching scratch buffer in mlx5_modify_lag() is converted from a
MLX5_MAX_PORTS-sized stack array to a kcalloc() of the same extent, with
the trailing teardown reworked through a goto so the buffer is freed on
every path. The memcpy() that previously relied on sizeof() of the stack
array now uses the explicit ldev->ports * MLX5_LAG_MAX_HASH_BUCKETS
span.

No functional change; this removes v2p_map's dependency on
MLX5_MAX_PORTS.

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Akiva Goldberger <agoldberger@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 .../net/ethernet/mellanox/mlx5/core/lag/lag.c | 38 ++++++++++++++-----
 .../net/ethernet/mellanox/mlx5/core/lag/lag.h |  2 +-
 2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
index c655f6e32e9b..00b0159cb422 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
@@ -308,6 +308,7 @@ static void mlx5_ldev_free(struct kref *ref)
 	cancel_work_sync(&ldev->speed_update_work);
 	destroy_workqueue(ldev->wq);
 	mutex_destroy(&ldev->lock);
+	kfree(ldev->v2p_map);
 	kfree(ldev);
 }
 
@@ -330,11 +331,16 @@ static struct mlx5_lag *mlx5_lag_dev_alloc(struct mlx5_core_dev *dev)
 	if (!ldev)
 		return NULL;
 
+	ldev->ports = MLX5_CAP_GEN(dev, num_lag_ports);
+	ldev->buckets = 1;
+	ldev->v2p_map = kcalloc(ldev->ports * MLX5_LAG_MAX_HASH_BUCKETS,
+				sizeof(*ldev->v2p_map), GFP_KERNEL);
+	if (!ldev->v2p_map)
+		goto err_v2p_map;
+
 	ldev->wq = create_singlethread_workqueue("mlx5_lag");
-	if (!ldev->wq) {
-		kfree(ldev);
-		return NULL;
-	}
+	if (!ldev->wq)
+		goto err_wq;
 
 	kref_init(&ldev->ref);
 	mutex_init(&ldev->lock);
@@ -358,10 +364,13 @@ static struct mlx5_lag *mlx5_lag_dev_alloc(struct mlx5_core_dev *dev)
 		mlx5_core_err(dev, "Failed to init multipath lag err=%d\n",
 			      err);
 
-	ldev->ports = MLX5_CAP_GEN(dev, num_lag_ports);
-	ldev->buckets = 1;
-
 	return ldev;
+
+err_wq:
+	kfree(ldev->v2p_map);
+err_v2p_map:
+	kfree(ldev);
+	return NULL;
 }
 
 int mlx5_lag_dev_get_netdev_idx(struct mlx5_lag *ldev,
@@ -853,8 +862,8 @@ void mlx5_modify_lag(struct mlx5_lag *ldev,
 		     struct lag_tracker *tracker)
 {
 	int first_idx = mlx5_lag_get_dev_index_by_seq(ldev, MLX5_LAG_P1);
-	u8 ports[MLX5_MAX_PORTS * MLX5_LAG_MAX_HASH_BUCKETS] = {};
 	struct mlx5_core_dev *dev0;
+	u8 *ports;
 	int idx;
 	int err;
 	int i;
@@ -864,6 +873,12 @@ void mlx5_modify_lag(struct mlx5_lag *ldev,
 		return;
 
 	dev0 = mlx5_lag_pf(ldev, first_idx)->dev;
+
+	ports = kcalloc(ldev->ports * MLX5_LAG_MAX_HASH_BUCKETS,
+			sizeof(*ports), GFP_KERNEL);
+	if (!ports)
+		return;
+
 	mlx5_infer_tx_affinity_mapping(tracker, ldev, ldev->buckets, ports);
 
 	mlx5_ldev_for_each(i, 0, ldev) {
@@ -876,9 +891,10 @@ void mlx5_modify_lag(struct mlx5_lag *ldev,
 				mlx5_core_err(dev0,
 					      "Failed to modify LAG (%d)\n",
 					      err);
-				return;
+				goto out;
 			}
-			memcpy(ldev->v2p_map, ports, sizeof(ports));
+			memcpy(ldev->v2p_map, ports,
+			       ldev->ports * MLX5_LAG_MAX_HASH_BUCKETS);
 
 			mlx5_lag_print_mapping(dev0, ldev, tracker,
 					       ldev->mode_flags);
@@ -899,6 +915,8 @@ void mlx5_modify_lag(struct mlx5_lag *ldev,
 					     ndev);
 		dev_put(ndev);
 	}
+out:
+	kfree(ports);
 }
 
 static int mlx5_lag_set_port_sel_mode(struct mlx5_lag *ldev,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
index e9f0ef83ce1d..8552792b9035 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
@@ -85,7 +85,7 @@ struct mlx5_lag {
 	u8			  ports;
 	u8			  buckets;
 	int			  mode_changes_in_progress;
-	u8			  v2p_map[MLX5_MAX_PORTS * MLX5_LAG_MAX_HASH_BUCKETS];
+	u8			  *v2p_map;
 	struct kref               ref;
 	struct xarray             pfs;
 	struct lag_tracker        tracker;
-- 
2.44.0