From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754297AbZJUQUc (ORCPT ); Wed, 21 Oct 2009 12:20:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754005AbZJUQUc (ORCPT ); Wed, 21 Oct 2009 12:20:32 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:58894 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753901AbZJUQUb (ORCPT ); Wed, 21 Oct 2009 12:20:31 -0400 Subject: Re: [PATCH 2/4] tracing: fix trace_seq_printf return value From: Steven Rostedt Reply-To: rostedt@goodmis.org To: Jiri Olsa Cc: mingo@elte.hu, linux-kernel@vger.kernel.org In-Reply-To: <1256135801-1849-3-git-send-email-jolsa@redhat.com> References: <1256135801-1849-1-git-send-email-jolsa@redhat.com> <1256135801-1849-3-git-send-email-jolsa@redhat.com> Content-Type: text/plain Organization: Kihon Technologies Inc. Date: Wed, 21 Oct 2009 12:20:35 -0400 Message-Id: <1256142035.18347.3133.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2009-10-21 at 16:36 +0200, Jiri Olsa wrote: > I believe we want to return the number of written characters, > instead of the available buffer length. > > wbr, > jirka > > Signed-off-by: Jiri Olsa > --- > kernel/trace/trace_output.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c > index ed17565..e871125 100644 > --- a/kernel/trace/trace_output.c > +++ b/kernel/trace/trace_output.c > @@ -95,7 +95,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) > > s->len += ret; > > - return len; > + return ret; Actually the return value here is ambiguous. Returning len is actually safer. It probably should only return 0 (buffer not big enough to write to) or 1 (buffer is big enough). Because this should actually return non zero: trace_seq_printf(s, ""); -- Steve > } > EXPORT_SYMBOL_GPL(trace_seq_printf); >