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

[Bart Van Assche <bvanassche@acm.org>]

On 2020-05-08 14:25, Arnd Bergmann wrote:
> On Fri, May 8, 2020 at 1:16 AM Bart Van Assche <bvanassche@acm.org> wrote:
>>
>> On 2020-05-07 15:00, Nick Desaulniers wrote:
>>> On Thu, May 7, 2020 at 12:18 PM kbuild test robot <lkp@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.
> 
> 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)

Bart.