[PATCH net] net/mlx4_core: Fix use of ENOSPC around mlx4_counter_alloc()

[Tariq Toukan]

When ENOSPC is set the idx is still valid and gets set to the global
MLX4_SINK_COUNTER_INDEX.  However gcc's static analysis cannot tell that
ENOSPC is impossible from mlx4_cmd_imm() and gives this warning:

drivers/net/ethernet/mellanox/mlx4/main.c:2552:28: warning: 'idx' may be
used uninitialized in this function [-Wmaybe-uninitialized]
 2552 |    priv->def_counter[port] = idx;

Also, when ENOSPC is returned mlx4_allocate_default_counters should not
fail.

Fixes: 6de5f7f6a1fa ("net/mlx4_core: Allocate default counter per port")
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Signed-off-by: Tariq Toukan <tar...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx4/main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c 
b/drivers/net/ethernet/mellanox/mlx4/main.c
index 5716c3d2bb86..c72c4e1ea383 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -2550,6 +2550,7 @@ static int mlx4_allocate_default_counters(struct mlx4_dev 
*dev)
 
                if (!err || err == -ENOSPC) {
                        priv->def_counter[port] = idx;
+                       err = 0;
                } else if (err == -ENOENT) {
                        err = 0;
                        continue;
@@ -2600,7 +2601,8 @@ int mlx4_counter_alloc(struct mlx4_dev *dev, u32 *idx, u8 
usage)
                                   MLX4_CMD_TIME_CLASS_A, MLX4_CMD_WRAPPED);
                if (!err)
                        *idx = get_param_l(&out_param);
-
+               if (WARN_ON(err == -ENOSPC))
+                       err = -EINVAL;
                return err;
        }
        return __mlx4_counter_alloc(dev, idx);
-- 
2.21.0