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Commit 13f16d20 authored by Li Zefan's avatar Li Zefan Committed by Frederic Weisbecker
Browse files

tracing: Use seq file for trace_clock 



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: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B1DC4FB.5030407@cn.fujitsu.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent fdb372ed

kernel/trace/trace.c

+15 −9
Original line number Diff line number Diff line
@@ -3366,21 +3366,18 @@ 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,
@@ -3422,6 +3419,13 @@ 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,
@@ -3460,8 +3464,10 @@ 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,

};