Ido Schimmel <ido...@idosch.org> writes:
> On Mon, Aug 17, 2020 at 10:38:24AM -0500, Bjorn Helgaas wrote:
>> You've likely seen this already, but Coverity found this problem:
>>
>> *** CID 1466147: Control flow issues (DEADCODE)
>> /drivers/net/ethernet/mellanox/mlxsw/spectrum_policer.c: 380 in
>> mlxsw_sp_policers_init()
>> 374 }
>> 375
>> 376 return 0;
>> 377
>> 378 err_family_register:
>> 379 for (i--; i >= 0; i--) {
>> >>> CID 1466147: Control flow issues (DEADCODE)
>> >>> Execution cannot reach this statement: "struct
>> mlxsw_sp_policer_fam...".
>> 380 struct mlxsw_sp_policer_family *family;
>> 381
>> 382 family = mlxsw_sp->policer_core->family_arr[i];
>> 383 mlxsw_sp_policer_family_unregister(mlxsw_sp, family);
>> 384 }
>> 385 err_init:
>>
>> I think the problem is that MLXSW_SP_POLICER_TYPE_MAX is 0 because
>>
>> > +enum mlxsw_sp_policer_type {
>> > + MLXSW_SP_POLICER_TYPE_SINGLE_RATE,
>> > +
>> > + __MLXSW_SP_POLICER_TYPE_MAX,
>> > + MLXSW_SP_POLICER_TYPE_MAX = __MLXSW_SP_POLICER_TYPE_MAX - 1,
>> > +};
>>
>> so we can only execute the family_register loop once, with i == 0,
>> and if we get to err_family_register via the error exit:
>>
>> > + for (i = 0; i < MLXSW_SP_POLICER_TYPE_MAX + 1; i++) {
>> > + err = mlxsw_sp_policer_family_register(mlxsw_sp,
>> > mlxsw_sp_policer_family_arr[i]);
>> > + if (err)
>> > + goto err_family_register;
>>
>> i will be 0, so i-- sets i to -1, so we don't enter the
>> family_unregister loop body since -1 is not >= 0.
>
> Thanks for the report, but isn't the code doing the right thing here? I
> mean, it's dead code now, but as soon as we add another family it will
> be executed. It seems error prone to remove it only to please Coverity
> and then add it back when it's actually needed.
Agreed.
