net/mlx5: reduce stack usage in qp_read_field

Moving the mlx5_ifc_query_qp_out_bits structure on the stack was a bit
excessive and now causes the compiler to complain on 32-bit architectures:

drivers/net/ethernet/mellanox/mlx5/core/debugfs.c: In function 'qp_read_field':
drivers/net/ethernet/mellanox/mlx5/core/debugfs.c:274:1: error: the frame size of 1104 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Revert the previous patch partially to use dynamically allocation as
the code did before. Unfortunately there is no good error handling
in case the allocation fails.

Fixes: 18dfdbdbcb2f ("net/mlx5: Replace hand written QP context struct with automatic getters")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c b/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
index 6409090b3ec52f7b2025e05305086bf1792f77f0..d2d57213511be2c8fe2fa24a76b348757b423437 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
@@ -202,18 +202,23 @@ void mlx5_cq_debugfs_cleanup(struct mlx5_core_dev *dev)
 static u64 qp_read_field(struct mlx5_core_dev *dev, struct mlx5_core_qp *qp,
                         int index, int *is_str)
 {
-       u32 out[MLX5_ST_SZ_BYTES(query_qp_out)] = {};
+       int outlen = MLX5_ST_SZ_BYTES(query_qp_out);
        u32 in[MLX5_ST_SZ_DW(query_qp_in)] = {};
        u64 param = 0;
+       u32 *out;
        int state;
        u32 *qpc;
        int err;
 
+       out = kzalloc(outlen, GFP_KERNEL);
+       if (!out)
+               return 0;
+
        MLX5_SET(query_qp_in, in, opcode, MLX5_CMD_OP_QUERY_QP);
        MLX5_SET(query_qp_in, in, qpn, qp->qpn);
        err = mlx5_cmd_exec_inout(dev, query_qp, in, out);
        if (err)
-               return 0;
+               goto out;
 
        *is_str = 0;
 
@@ -269,7 +274,8 @@ static u64 qp_read_field(struct mlx5_core_dev *dev, struct mlx5_core_qp *qp,
                param = MLX5_GET(qpc, qpc, remote_qpn);
                break;
        }
-
+out:
+       kfree(out);
        return param;
 }