From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935803AbZLHDQg (ORCPT ); Mon, 7 Dec 2009 22:16:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934700AbZLHDQd (ORCPT ); Mon, 7 Dec 2009 22:16:33 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:55074 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S934801AbZLHDQ3 (ORCPT ); Mon, 7 Dec 2009 22:16:29 -0500 Message-ID: <4B1DC4FB.5030407@cn.fujitsu.com> Date: Tue, 08 Dec 2009 11:16:11 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Ingo Molnar CC: Steven Rostedt , Frederic Weisbecker , LKML Subject: [PATCH 08/13] tracing: Use seq file for trace_clock References: <4B1DC476.3030700@cn.fujitsu.com> In-Reply-To: <4B1DC476.3030700@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The buffer for the output is as small as 64 bytes, so it'll overflow if we add more clock type. Use seq file instead. Signed-off-by: Li Zefan --- kernel/trace/trace.c | 24 +++++++++++++++--------- 1 files changed, 15 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e989fc9..75871e5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3327,21 +3327,18 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, return cnt; } -static ssize_t tracing_clock_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) +static int tracing_clock_show(struct seq_file *m, void *v) { - char buf[64]; - int bufiter = 0; int i; for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) - bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, + seq_printf(m, "%s%s%s%s", i ? " " : "", i == trace_clock_id ? "[" : "", trace_clocks[i].name, i == trace_clock_id ? "]" : ""); - bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, "\n"); + seq_putc(m, '\n'); - return simple_read_from_buffer(ubuf, cnt, ppos, buf, bufiter); + return 0; } static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, @@ -3383,6 +3380,13 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, return cnt; } +static int tracing_clock_open(struct inode *inode, struct file *file) +{ + if (tracing_disabled) + return -ENODEV; + return single_open(file, tracing_clock_show, NULL); +} + static const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, @@ -3421,8 +3425,10 @@ static const struct file_operations tracing_mark_fops = { }; static const struct file_operations trace_clock_fops = { - .open = tracing_open_generic, - .read = tracing_clock_read, + .open = tracing_clock_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, .write = tracing_clock_write, }; -- 1.6.3