On 10/16/23 6:49 AM, Geert Uytterhoeven wrote:
> When CONFIG_IPV6=n, and building with W=1:
>
> In file included from include/trace/define_trace.h:102,
> from include/trace/events/neigh.h:255,
> from net/core/net-traces.c:51:
> include/trace/events/neigh.h: In function
> ‘trace_event_raw_event_neigh_create’:
> include/trace/events/neigh.h:42:34: error: variable ‘pin6’ set but not
> used [-Werror=unused-but-set-variable]
> 42 | struct in6_addr *pin6;
> | ^~~~
> include/trace/trace_events.h:402:11: note: in definition of macro
> ‘DECLARE_EVENT_CLASS’
> 402 | { assign; }
> \
> | ^~~~~~
> include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
> 44 | PARAMS(assign), \
> | ^~~~~~
> include/trace/events/neigh.h:23:1: note: in expansion of macro
> ‘TRACE_EVENT’
> 23 | TRACE_EVENT(neigh_create,
> | ^~~~~~~~~~~
> include/trace/events/neigh.h:41:9: note: in expansion of macro
> ‘TP_fast_assign’
> 41 | TP_fast_assign(
> | ^~~~~~~~~~~~~~
> In file included from include/trace/define_trace.h:103,
> from include/trace/events/neigh.h:255,
> from net/core/net-traces.c:51:
> include/trace/events/neigh.h: In function ‘perf_trace_neigh_create’:
> include/trace/events/neigh.h:42:34: error: variable ‘pin6’ set but not
> used [-Werror=unused-but-set-variable]
> 42 | struct in6_addr *pin6;
> | ^~~~
> include/trace/perf.h:51:11: note: in definition of macro
> ‘DECLARE_EVENT_CLASS’
> 51 | { assign; }
> \
> | ^~~~~~
> include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
> 44 | PARAMS(assign), \
> | ^~~~~~
> include/trace/events/neigh.h:23:1: note: in expansion of macro
> ‘TRACE_EVENT’
> 23 | TRACE_EVENT(neigh_create,
> | ^~~~~~~~~~~
> include/trace/events/neigh.h:41:9: note: in expansion of macro
> ‘TP_fast_assign’
> 41 | TP_fast_assign(
> | ^~~~~~~~~~~~~~
>
> Indeed, the variable pin6 is declared and initialized unconditionally,
> while it is only used and needlessly re-initialized when support for
> IPv6 is enabled.
>
> Fix this by dropping the unused variable initialization, and moving the
> variable declaration inside the existing section protected by a check
> for CONFIG_IPV6.
>
> Fixes: fc651001d2c5ca4f ("neighbor: Add tracepoint to __neigh_create")
> Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
> ---
> No changes in generated code.
>
> include/trace/events/neigh.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
Reviewed-by: David Ahern <dsah...@kernel.org>
Google put your email in the spam folder, BTW.
