[PATCH v12 net-next 2/9] net/mlx5e: trim stack use in PCIe congestion threshold helper

[Ratheesh Kannoth]

union devlink_param_value grew when U64 array parameters were added.
Keeping a four-element array of that union in
mlx5e_pcie_cong_get_thresh_config() inflated the stack frame past the
-Wframe-larger-than limit.

Read each driverinit value into a single reused union, then store the
four u16 thresholds in struct mlx5e_pcie_cong_thresh field order via a
temporary u16 pointer to config.

Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>
---
 .../mellanox/mlx5/core/en/pcie_cong_event.c   | 34 +++++++++++--------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/pcie_cong_event.c b/drivers/net/ethernet/mellanox/mlx5/core/en/pcie_cong_event.c
index 2eb666a46f39..88e76be3a73d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/pcie_cong_event.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/pcie_cong_event.c
@@ -252,28 +252,32 @@ static int
 mlx5e_pcie_cong_get_thresh_config(struct mlx5_core_dev *dev,
 				  struct mlx5e_pcie_cong_thresh *config)
 {
+	enum {
+		INBOUND_HIGH,
+		INBOUND_LOW,
+		OUTBOUND_HIGH,
+		OUTBOUND_LOW,
+	};
+
 	u32 ids[4] = {
-		MLX5_DEVLINK_PARAM_ID_PCIE_CONG_IN_LOW,
-		MLX5_DEVLINK_PARAM_ID_PCIE_CONG_IN_HIGH,
-		MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_LOW,
-		MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_HIGH,
+		[INBOUND_LOW] = MLX5_DEVLINK_PARAM_ID_PCIE_CONG_IN_LOW,
+		[INBOUND_HIGH] = MLX5_DEVLINK_PARAM_ID_PCIE_CONG_IN_HIGH,
+		[OUTBOUND_LOW] = MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_LOW,
+		[OUTBOUND_HIGH] = MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_HIGH,
 	};
-	struct devlink *devlink = priv_to_devlink(dev);
-	union devlink_param_value val[4];
 
-	for (int i = 0; i < 4; i++) {
-		u32 id = ids[i];
-		int err;
+	struct devlink *devlink = priv_to_devlink(dev);
+	union devlink_param_value val;
+	u16 *dst = (u16 *)config;
+	int err;
 
-		err = devl_param_driverinit_value_get(devlink, id, &val[i]);
+	for (int i = 0; i < ARRAY_SIZE(ids); i++) {
+		err = devl_param_driverinit_value_get(devlink, ids[i], &val);
 		if (err)
 			return err;
-	}
 
-	config->inbound_low = val[0].vu16;
-	config->inbound_high = val[1].vu16;
-	config->outbound_low = val[2].vu16;
-	config->outbound_high = val[3].vu16;
+		dst[i] = val.vu16;
+	}
 
 	return 0;
 }
-- 
2.43.0