Hello Eran Ben Elisha,
The patch cef35af34d6d: "net/mlx5e: Add mlx5e HV VHCA stats agent"
from Aug 22, 2019, leads to the following static checker warning:
drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c:41 mlx5e_hv_vhca_fill_stats()
warn: potential pointer math issue ('buf' is a u64 pointer)
drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c
33 static void mlx5e_hv_vhca_fill_stats(struct mlx5e_priv *priv, u64 *data,
^^^^^^^^^
data is a u64 pointer.
34 int buf_len)
35 {
36 int ch, i = 0;
37
38 for (ch = 0; ch < priv->max_nch; ch++) {
39 u64 *buf = data + i;
^^^^^^^^
40
41 if (WARN_ON_ONCE(buf +
42 sizeof(struct mlx5e_hv_vhca_per_ring_stats) >
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This pointer math doesn't work. I'm surprised the warning doesn't
trigger.
43 data + buf_len))
44 return;
45
46 mlx5e_hv_vhca_fill_ring_stats(priv, ch,
47 (struct mlx5e_hv_vhca_per_ring_stats *)buf);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If we made both "data" and "buf" void pointers then this would be
much easier and the casting could be removed.
48 i += sizeof(struct mlx5e_hv_vhca_per_ring_stats) / sizeof(u64);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This math works, but it's so complicated and you have to verify that
mlx5e_hv_vhca_per_ring_stats % sizeof(u64) is zero.
49 }
50 }
regards,
dan carpenter
