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tracing/events: simplify system_enable_read()

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

[ Impact: clean up ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A0399A5.2080603@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-05-08 10:32:05 +08:00 committed by Ingo Molnar
parent 8f31bfe538
commit c142b15dc5
1 changed files with 6 additions and 34 deletions
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40
kernel/trace/trace_events.c
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@ -414,10 +414,11 @@ static ssize_t
system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos) loff_t *ppos)
{ {
const char set_to_char[4] = { '?', '0', '1', 'X' };
const char *system = filp->private_data; const char *system = filp->private_data;
struct ftrace_event_call *call; struct ftrace_event_call *call;
char buf[2]; char buf[2];
int set = -1; int set = 0;
int ret; int ret;
mutex_lock(&event_mutex); 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 * or if all events or cleared, or if we have
* a mixture. * a mixture.
*/ */
if (call->enabled) { set |= (1 << !!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;
}
}
/* /*
* If we have a mixture, no need to look further. * If we have a mixture, no need to look further.
*/ */
if (set == 2) if (set == 3)
break; break;
} }
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);
buf[0] = set_to_char[set];
buf[1] = '\n'; 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); ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);