Re: Clang warning in drivers/net/ethernet/intel/igc/igc_ethtool.c

From: Michal Kubecek
Date: Fri Feb 08 2019 - 09:34:08 EST

On Thu, Feb 07, 2019 at 10:09:21PM -0700, Nathan Chancellor wrote:
> Hi all,
> After commit 8c5ad0dae93c ("igc: Add ethtool support"), Clang warns:
> drivers/net/ethernet/intel/igc/igc_ethtool.c:9:19: warning: variable 'igc_priv_flags_strings' is not needed and will not be emitted [-Wunneeded-internal-declaration]
> static const char igc_priv_flags_strings[][ETH_GSTRING_LEN] = {
> ^
> 1 warning generated.
> igc_priv_flags_strings is only used in an ARRAY_SIZE macro, which is a
> compile time evaluation, so no reference to it is being emitted in the
> final assembly. Is it actually needed and was forgotten to be used
> somewhere or could it be eliminated so that Clang no longer warns?

That's because the driver provides get_priv_flags() and set_priv_flags()
callbacks in its ethtool_ops to allow querying and setting legacy-rx
private flag but it does not provide get_sset_count() and get_strings()
to provide list of private flags to userspace ethtool.

Michal Kubecek