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tracing: add options directory and core option files 

This patch creates an options directory in the debugfs, that contains
the available tracing options. These files contain 1 or 0, where 1
is the option is enabled and 0 it is disabled.

Simply echoing in 1 will enable the option and 0 will disable it.
This patch only contains the core options, not the tracer options.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2009-02-26 22:19:12 -05:00
parent 5d0859cef2
commit a825907507
1 changed files with 117 additions and 0 deletions
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117
kernel/trace/trace.c
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@ -3093,6 +3093,121 @@ static void tracing_init_debugfs_percpu(long cpu)
#include "trace_selftest.c"
#endif
static ssize_t
trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
long index = (long)filp->private_data;
char *buf;
if (trace_flags & (1 << index))
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
long index = (long)filp->private_data;
char buf[64];
unsigned long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
return ret;
switch (val) {
case 0:
trace_flags &= ~(1 << index);
break;
case 1:
trace_flags |= 1 << index;
break;
default:
return -EINVAL;
}
*ppos += cnt;
return cnt;
}
static const struct file_operations trace_options_core_fops = {
.open = tracing_open_generic,
.read = trace_options_core_read,
.write = trace_options_core_write,
};
static struct dentry *trace_options_init_dentry(void)
{
struct dentry *d_tracer;
static struct dentry *t_options;
if (t_options)
return t_options;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return NULL;
t_options = debugfs_create_dir("options", d_tracer);
if (!t_options) {
pr_warning("Could not create debugfs directory 'options'\n");
return NULL;
}
return t_options;
}
static struct dentry *
create_trace_option_core_file(const char *option, long index)
{
struct dentry *t_options;
struct dentry *entry;
t_options = trace_options_init_dentry();
if (!t_options)
return NULL;
entry = debugfs_create_file(option, 0644, t_options, (void *)index,
&trace_options_core_fops);
return entry;
}
static __init void create_trace_options_dir(void)
{
struct dentry *t_options;
struct dentry *entry;
int i;
t_options = trace_options_init_dentry();
if (!t_options)
return;
for (i = 0; trace_options[i]; i++) {
entry = create_trace_option_core_file(trace_options[i], i);
if (!entry)
pr_warning("Could not create debugfs %s entry\n",
trace_options[i]);
}
}
static __init int tracer_init_debugfs(void)
{
struct dentry *d_tracer;
@ -3111,6 +3226,8 @@ static __init int tracer_init_debugfs(void)
if (!entry)
pr_warning("Could not create debugfs 'trace_options' entry\n");
create_trace_options_dir();
entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
NULL, &tracing_cpumask_fops);
if (!entry)