From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752672AbZJWXhb (ORCPT ); Fri, 23 Oct 2009 19:37:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752288AbZJWXgp (ORCPT ); Fri, 23 Oct 2009 19:36:45 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:60660 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752120AbZJWXgm (ORCPT ); Fri, 23 Oct 2009 19:36:42 -0400 Message-Id: <20091023233646.631787612@goodmis.org> User-Agent: quilt/0.48-1 Date: Fri, 23 Oct 2009 19:36:17 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Frederic Weisbecker , Jiri Olsa Subject: [PATCH 2/4] [PATCH 2/4] tracing: fix trace_seq_printf return value References: <20091023233615.661789185@goodmis.org> Content-Disposition: inline; filename=0002-tracing-fix-trace_seq_printf-return-value.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa trace_seq_printf return value is a little ambiguous. It currently returns the length of the space available in the buffer. printf usually returns the amount written. This is not adequate here, because trace_seq_printf(s, ""); is perfectly legal, and returning 0 would indicate that it failed. We can always see the amount written by looking at the before and after values of s->len. This is not quite the same use as printf. We only care if the string was successfully written to the buffer or not. Making trace_seq_printf return 0 if the trace oversizes the buffer's free space, 1 otherwise. Signed-off-by: Jiri Olsa LKML-Reference: <20091022120958.GB2311@jolsa.redhat.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_output.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index ed17565..b6c12c6 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -69,6 +69,9 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter) * @s: trace sequence descriptor * @fmt: printf format string * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * * The tracer may use either sequence operations or its own * copy to user routines. To simplify formating of a trace * trace_seq_printf is used to store strings into a special @@ -95,7 +98,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) s->len += ret; - return len; + return 1; } EXPORT_SYMBOL_GPL(trace_seq_printf); -- 1.6.3.3