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tracing: Move the pid_list seq_file functions to be global

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To allow other aspects of ftrace to use the pid_list logic, we need to reuse
the seq_file functions. Making the generic part into functions that can be
called by other files will help in this regard.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2016-04-20 15:19:54 -04:00 committed by Steven Rostedt
parent d8275c454d
commit 5cc8976bd5
3 changed files with 77 additions and 31 deletions
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71
kernel/trace/trace.c
View File

@ -397,6 +397,77 @@ void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
clear_bit(task->pid, pid_list->pids);
}
/**
* trace_pid_next - Used for seq_file to get to the next pid of a pid_list
* @pid_list: The pid list to show
* @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
* @pos: The position of the file
*
* This is used by the seq_file "next" operation to iterate the pids
* listed in a trace_pid_list structure.
*
* Returns the pid+1 as we want to display pid of zero, but NULL would
* stop the iteration.
*/
void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
{
unsigned long pid = (unsigned long)v;
(*pos)++;
/* pid already is +1 of the actual prevous bit */
pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
/* Return pid + 1 to allow zero to be represented */
if (pid < pid_list->pid_max)
return (void *)(pid + 1);
return NULL;
}
/**
* trace_pid_start - Used for seq_file to start reading pid lists
* @pid_list: The pid list to show
* @pos: The position of the file
*
* This is used by seq_file "start" operation to start the iteration
* of listing pids.
*
* Returns the pid+1 as we want to display pid of zero, but NULL would
* stop the iteration.
*/
void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
{
unsigned long pid;
loff_t l = 0;
pid = find_first_bit(pid_list->pids, pid_list->pid_max);
if (pid >= pid_list->pid_max)
return NULL;
/* Return pid + 1 so that zero can be the exit value */
for (pid++; pid && l < *pos;
pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
;
return (void *)pid;
}
/**
* trace_pid_show - show the current pid in seq_file processing
* @m: The seq_file structure to write into
* @v: A void pointer of the pid (+1) value to display
*
* Can be directly used by seq_file operations to display the current
* pid value.
*/
int trace_pid_show(struct seq_file *m, void *v)
{
unsigned long pid = (unsigned long)v - 1;
seq_printf(m, "%lu\n", pid);
return 0;
}
static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
{
u64 ts;

3
kernel/trace/trace.h
View File

@ -636,6 +636,9 @@ bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
struct task_struct *self,
struct task_struct *task);
void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos);
void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos);
int trace_pid_show(struct seq_file *m, void *v);
#ifdef CONFIG_TRACER_MAX_TRACE
void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);

34
kernel/trace/trace_events.c
View File

@ -983,18 +983,8 @@ p_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_array *tr = m->private;
struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
unsigned long pid = (unsigned long)v;
(*pos)++;
/* pid already is +1 of the actual prevous bit */
pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
/* Return pid + 1 to allow zero to be represented */
if (pid < pid_list->pid_max)
return (void *)(pid + 1);
return NULL;
return trace_pid_next(pid_list, v, pos);
}
static void *p_start(struct seq_file *m, loff_t *pos)
@ -1002,8 +992,6 @@ static void *p_start(struct seq_file *m, loff_t *pos)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = m->private;
unsigned long pid;
loff_t l = 0;
/*
* Grab the mutex, to keep calls to p_next() having the same
@ -1019,15 +1007,7 @@ static void *p_start(struct seq_file *m, loff_t *pos)
if (!pid_list)
return NULL;
pid = find_first_bit(pid_list->pids, pid_list->pid_max);
if (pid >= pid_list->pid_max)
return NULL;
/* Return pid + 1 so that zero can be the exit value */
for (pid++; pid && l < *pos;
pid = (unsigned long)p_next(m, (void *)pid, &l))
;
return (void *)pid;
return trace_pid_start(pid_list, pos);
}
static void p_stop(struct seq_file *m, void *p)
@ -1037,14 +1017,6 @@ static void p_stop(struct seq_file *m, void *p)
mutex_unlock(&event_mutex);
}
static int p_show(struct seq_file *m, void *v)
{
unsigned long pid = (unsigned long)v - 1;
seq_printf(m, "%lu\n", pid);
return 0;
}
static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
@ -1795,7 +1767,7 @@ static const struct seq_operations show_set_event_seq_ops = {
static const struct seq_operations show_set_pid_seq_ops = {
.start = p_start,
.next = p_next,
.show = p_show,
.show = trace_pid_show,
.stop = p_stop,
};