Re: [PATCH v5 02/11] qla2xxx: Suppress two recently introduced compiler warnings

[kbuild test robot]

Hi Bart,

I love your patch! Yet something to improve:

[auto build test ERROR on scsi/for-next]
[also build test ERROR on mkp-scsi/for-next tip/perf/core v5.7-rc4 next-20200507]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url: https://github.com/0day-ci/linux/commits/Bart-Van-Assche/Fix-qla2xxx-endianness-annotations/20200507-135245
base: https://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git for-next
config: x86_64-allyesconfig (attached as .config)
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 54b35c066417d4856e9d53313f7e98b354274584)
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <l...@intel.com>

All errors (new ones prefixed by >>):

In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:95:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:155:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:222:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:402:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:453:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:533:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:727:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:792:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:103:
In file included from include/trace/perf.h:90:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
In file included from include/trace/events/qla.h:44:
In file included from include/trace/define_trace.h:104:
In file included from include/trace/bpf_probe.h:114:
>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
^
11 errors generated.

vim +13 include/trace/events/qla.h

11
12 #pragma GCC diagnostic push
> 13 #pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
14

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuil...@lists.01.org

[Nick Desaulniers]

Hi Bart,
These compiler specific pragma's are not toolchain portable. You'll
need to wrap them in:
#ifndef __clang__
preprocessor macros, or I think we have a pragma helper in tree that
helps with compiler specific pragmas. IIRC it uses _Pragma to define
pragmas in macros.

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--
Thanks,
~Nick Desaulniers

[Bart Van Assche]

On 2020-05-07 15:00, Nick Desaulniers wrote:
> On Thu, May 7, 2020 at 12:18 PM kbuild test robot <l...@intel.com> wrote:
>> All errors (new ones prefixed by >>):
>>
>> In file included from drivers/scsi/qla2xxx/qla_dbg.c:77:
>>>> include/trace/events/qla.h:13:32: error: unknown warning group '-Wsuggest-attribute=format', ignored [-Werror,-Wunknown-warning-option]
>> #pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
>> ^
>
> Hi Bart,
> These compiler specific pragma's are not toolchain portable. You'll
> need to wrap them in:
> #ifndef __clang__
> preprocessor macros, or I think we have a pragma helper in tree that
> helps with compiler specific pragmas. IIRC it uses _Pragma to define
> pragmas in macros.

Hi Nick,

Thanks for the feedback. I will have a look at _Pragma() and see what
the best way is to suppress this warning.

Bart.

[Arnd Bergmann]

The __diag_ignore() macro in linux/compiler.h should work for this.

Arnd

[Bart Van Assche]

Thanks Arnd, that's good to know. Is using __diag_ignore() mandatory in
this case? The following construct seems to work fine with both gcc and
clang:

#define QLA_MSG_MAX 256

+#pragma GCC diagnostic push
+#ifndef __clang__
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+#endif
+
DECLARE_EVENT_CLASS(qla_log_event,
TP_PROTO(const char *buf,
struct va_format *vaf),
@@ -27,6 +32,8 @@ DECLARE_EVENT_CLASS(qla_log_event,
TP_printk("%s %s", __get_str(buf), __get_str(msg))
);

+#pragma GCC diagnostic pop
+
DEFINE_EVENT(qla_log_event, ql_dbg_log,
TP_PROTO(const char *buf, struct va_format *vaf),
TP_ARGS(buf, vaf)

Bart.

[Arnd Bergmann]

On Sat, May 9, 2020 at 12:29 AM Bart Van Assche <bvana...@acm.org> wrote:
>
> >> Thanks for the feedback. I will have a look at _Pragma() and see what
> >> the best way is to suppress this warning.
> >
> > The __diag_ignore() macro in linux/compiler.h should work for this.
>
> Thanks Arnd, that's good to know. Is using __diag_ignore() mandatory in
> this case? The following construct seems to work fine with both gcc and
> clang:
>
> #define QLA_MSG_MAX 256
>
> +#pragma GCC diagnostic push
> +#ifndef __clang__
> +#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
> +#endif
> +
> DECLARE_EVENT_CLASS(qla_log_event,
> TP_PROTO(const char *buf,
> struct va_format *vaf),
> @@ -27,6 +32,8 @@ DECLARE_EVENT_CLASS(qla_log_event,
> TP_printk("%s %s", __get_str(buf), __get_str(msg))
> );
>
> +#pragma GCC diagnostic pop
> +
> DEFINE_EVENT(qla_log_event, ql_dbg_log,
> TP_PROTO(const char *buf, struct va_format *vaf),
> TP_ARGS(buf, vaf)

__diag_push(), __diag_ignore(), and __diag_pop() are just
shortcuts for open-coded #pragma plus #ifdef, they do
exactly the same thing here. I think it would be best to be
consistent and use the macros, but it works either way.

I actually have patches to introduce yet another syntax as part
of a larger rework, but that is still WiP.

Arnd