diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2009-03-13 00:12:52 -0400 |
|---|---|---|
| committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-13 00:15:46 -0400 |
| commit | bdc067582b8b71c7771bab076bbc51569c594fb4 (patch) | |
| tree | a202353e4e365ae29c5bf95ca33eacd8eb4dfb54 | |
| parent | eb1871f34358024acfa3523ef375ef14b7527173 (diff) | |
tracing: add comment for use of double __builtin_consant_p
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>
| -rw-r--r-- | 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 35cfa7bbaf3..67595b8f0f1 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); \ |