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Commit 5cc8976b authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Move the pid_list seq_file functions to be global 



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: default avatarSteven Rostedt <rostedt@goodmis.org>
parent d8275c45

kernel/trace/trace.c

+71 −0
Original line number Diff line number Diff line
@@ -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;

kernel/trace/trace.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

kernel/trace/trace_events.c

+3 −31
Original line number Diff line number Diff line
@@ -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,

};