net/mlx5e: Move and optimize query out of buffer function

Move "query queue counter out of buffer" helper function out of
qp.c to en_main.c, since mlx5e netdev driver is the only one to use it.

Also allocate the output buffer on the stack instead of the heap, to reduce
number of heap allocs on update_stats work.

Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Cc: kernel-team@fb.com

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

@@ -289,12 +289,17 @@ static void mlx5e_update_pport_counters(struct mlx5e_priv *priv)
 static void mlx5e_update_q_counter(struct mlx5e_priv *priv)
 {
 	struct mlx5e_qcounter_stats *qcnt = &priv->stats.qcnt;
+	u32 out[MLX5_ST_SZ_DW(query_q_counter_out)];
+	int err;
 
 	if (!priv->q_counter)
 		return;
 
-	mlx5_core_query_out_of_buffer(priv->mdev, priv->q_counter,
-				      &qcnt->rx_out_of_buffer);
+	err = mlx5_core_query_q_counter(priv->mdev, priv->q_counter, 0, out, sizeof(out));
+	if (err)
+		return;
+
+	qcnt->rx_out_of_buffer = MLX5_GET(query_q_counter_out, out, out_of_buffer);
 }
 
 static void mlx5e_update_pcie_counters(struct mlx5e_priv *priv)

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

@@ -518,23 +518,3 @@ int mlx5_core_query_q_counter(struct mlx5_core_dev *dev, u16 counter_id,
 	return mlx5_cmd_exec(dev, in, sizeof(in), out, out_size);
 }
 EXPORT_SYMBOL_GPL(mlx5_core_query_q_counter);
-
-int mlx5_core_query_out_of_buffer(struct mlx5_core_dev *dev, u16 counter_id,
-				  u32 *out_of_buffer)
-{
-	int outlen = MLX5_ST_SZ_BYTES(query_q_counter_out);
-	void *out;
-	int err;
-
-	out = kvzalloc(outlen, GFP_KERNEL);
-	if (!out)
-		return -ENOMEM;
-
-	err = mlx5_core_query_q_counter(dev, counter_id, 0, out, outlen);
-	if (!err)
-		*out_of_buffer = MLX5_GET(query_q_counter_out, out,
-					  out_of_buffer);
-
-	kfree(out);
-	return err;
-}

include/linux/mlx5/qp.h

@@ -569,8 +569,6 @@ int mlx5_core_alloc_q_counter(struct mlx5_core_dev *dev, u16 *counter_id);
 int mlx5_core_dealloc_q_counter(struct mlx5_core_dev *dev, u16 counter_id);
 int mlx5_core_query_q_counter(struct mlx5_core_dev *dev, u16 counter_id,
 			      int reset, void *out, int out_size);
-int mlx5_core_query_out_of_buffer(struct mlx5_core_dev *dev, u16 counter_id,
-				  u32 *out_of_buffer);
 
 static inline const char *mlx5_qp_type_str(int type)
 {