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Commit c142b15d authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

tracing/events: simplify system_enable_read() 



A smarter way to figure out the output of an enable file.

[ Impact: clean up ]

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A0399A5.2080603@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8f31bfe5

kernel/trace/trace_events.c

+6 −34
Original line number Diff line number Diff line
@@ -414,10 +414,11 @@ static ssize_t 
system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,

		   loff_t *ppos)

{

	const char set_to_char[4] = { '?', '0', '1', 'X' };

	const char *system = filp->private_data;

	struct ftrace_event_call *call;

	char buf[2];

	int set = -1;

	int set = 0;

	int ret;



	mutex_lock(&event_mutex);
@@ -433,47 +434,18 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 
		 * or if all events or cleared, or if we have

		 * a mixture.

		 */

		if (call->enabled) {

			switch (set) {

			case -1:

				set = 1;

				break;

			case 0:

				set = 2;

				break;

			}

		} else {

			switch (set) {

			case -1:

				set = 0;

				break;

			case 1:

				set = 2;

				break;

			}

		}

		set |= (1 << !!call->enabled);



		/*

		 * If we have a mixture, no need to look further.

		 */

		if (set == 2)

		if (set == 3)

			break;

	}

	mutex_unlock(&event_mutex);



	buf[0] = set_to_char[set];

	buf[1] = '\n';

	switch (set) {

	case 0:

		buf[0] = '0';

		break;

	case 1:

		buf[0] = '1';

		break;

	case 2:

		buf[0] = 'X';

		break;

	default:

		buf[0] = '?';

	}



	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);