[dpdk-dev] [PATCH v6 10/12] net/i40e: clean LTO build warnings (maybe-uninitialized)

[Andrzej Ostruszka]

Beilei

Thank you for the comment, please see below.

On 11/1/19 3:05 AM, Xing, Beilei wrote:
>> -----Original Message-----
>> From: Andrzej Ostruszka [mailto:aostruszka at marvell.com]
[...]
>> Subject: [PATCH v6 10/12] net/i40e: clean LTO build warnings (maybe-
>> uninitialized)
>>
>> During LTO build compiler reports some 'false positive' warnings about
>> variables being possibly used uninitialized.  This patch silences these warnings.
>>
>> Exemplary compiler warning to suppress (with LTO enabled):
>> error: ‘filter_idx’ may be used uninitialized in this function [-Werror=maybe-
>> uninitialized]
>>   PMD_DRV_LOG(INFO, "Added port %d with AQ command with index %d",
> 
> Hi,
> 
> Thanks for the patch. Please also add fix line here and Cc stable.

Are you saying that there is actually a problem in the code?

IMHO the code is fine and this patch just prevents gcc from issuing a
false warning.  What I think is going on is that gcc looks into
i40e_aq_add_udp_tunnel() and sees that filter_idx is updated under
condition "if (!status ..." and figures out that if status is positive
then filter_idx could be used uninitialized because in the calling
function we test "if (ret < 0)".  However it fails to take into account
the actual enum definition (only non-positive values) and the
implementation of i40e_asq_send_command().

So, if this is only work-around for the gcc deficiency, then I would
prefer to not add any fixline and to not pull that patch into stable.
Please let me know what you think.

Regards
Andrzej