From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758257AbZCMFJF (ORCPT ); Fri, 13 Mar 2009 01:09:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758034AbZCMFF1 (ORCPT ); Fri, 13 Mar 2009 01:05:27 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:64862 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758044AbZCMFFY (ORCPT ); Fri, 13 Mar 2009 01:05:24 -0400 Message-Id: <20090313050521.300766632@goodmis.org> References: <20090313050446.277065036@goodmis.org> User-Agent: quilt/0.46-1 Date: Fri, 13 Mar 2009 01:04:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Frederic Weisbecker , KOSAKI Motohiro , Steven Rostedt Subject: [PATCH 2/4] tracing: add comment for use of double __builtin_consant_p Content-Disposition: inline; filename=0002-tracing-add-comment-for-use-of-double-__builtin_con.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt 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 LKML-Reference: <20090313122235.43EB.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt --- 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 --