Messages in this thread Patch in this message | | | Date | Fri, 13 Mar 2009 01:04:48 -0400 | From | Steven Rostedt <> | Subject | [PATCH 2/4] tracing: add comment for use of double __builtin_consant_p |
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From: Steven Rostedt <srostedt@redhat.com>
Impact: documentation
The use of the double __builtin_contant_p checks in the event_trace_printk can be confusing to developers and reviewers. This patch adds a comment to explain why it is there.
Requested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20090313122235.43EB.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> --- kernel/trace/trace.h | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 35cfa7b..67595b8 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -776,6 +776,11 @@ extern struct ftrace_event_call __stop_ftrace_events[]; extern const char *__start___trace_bprintk_fmt[]; extern const char *__stop___trace_bprintk_fmt[]; +/* + * The double __builtin_constant_p is because gcc will give us an error + * if we try to allocate the static variable to fmt if it is not a + * constant. Even with the outer if statement optimizing out. + */ #define event_trace_printk(ip, fmt, args...) \ do { \ __trace_printk_check_format(fmt, ##args); \ -- 1.6.1.3 --
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