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Commit dbd3fbdf authored by Li Zefan's avatar Li Zefan Committed by Frederic Weisbecker
Browse files

tracing/stat: do some cleanups 



- remove duplicate code in stat_seq_init()
- update comments to reflect the change from stat list to stat rbtree

[ Impact: clean up ]

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent e1622806

kernel/trace/trace_stat.c

+21 −33
Original line number Diff line number Diff line
@@ -93,10 +93,15 @@ static void destroy_session(struct stat_session *session) 


typedef int (*cmp_stat_t)(void *, void *);



static void

insert_stat(struct rb_root *root, struct stat_node *data, cmp_stat_t cmp)

static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)

{

	struct rb_node **new = &(root->rb_node), *parent = NULL;

	struct stat_node *data;



	data = kzalloc(sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;

	data->stat = stat;



	/*

	 * Figure out where to put new node
@@ -118,12 +123,13 @@ insert_stat(struct rb_root *root, struct stat_node *data, cmp_stat_t cmp) 


	rb_link_node(&data->node, parent, new);

	rb_insert_color(&data->node, root);

	return 0;

}



/*

 * For tracers that don't provide a stat_cmp callback.

 * This one will force an immediate insertion on tail of

 * the list.

 * This one will force an insertion as right-most node

 * in the rbtree.

 */

static int dummy_cmp(void *p1, void *p2)

{
@@ -131,15 +137,14 @@ static int dummy_cmp(void *p1, void *p2) 
}



/*

 * Initialize the stat list at each trace_stat file opening.

 * Initialize the stat rbtree at each trace_stat file opening.

 * All of these copies and sorting are required on all opening

 * since the stats could have changed between two file sessions.

 */

static int stat_seq_init(struct stat_session *session)

{

	struct tracer_stat *ts = session->ts;

	struct stat_node *new_entry;

	struct rb_root *root;

	struct rb_root *root = &session->stat_root;

	void *stat;

	int ret = 0;

	int i;
@@ -154,23 +159,12 @@ static int stat_seq_init(struct stat_session *session) 
	if (!stat)

		goto exit;



	/*

	 * The first entry. Actually this is the second, but the first

	 * one (the stat_list head) is pointless.

	 */

	new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);

	if (!new_entry) {

		ret = -ENOMEM;

	ret = insert_stat(root, stat, ts->stat_cmp);

	if (ret)

		goto exit;

	}

	root = &session->stat_root;

	insert_stat(root, new_entry, dummy_cmp);



	new_entry->stat = stat;



	/*

	 * Iterate over the tracer stat entries and store them in a sorted

	 * list.

	 * Iterate over the tracer stat entries and store them in an rbtree.

	 */

	for (i = 1; ; i++) {

		stat = ts->stat_next(stat, i);
@@ -179,22 +173,16 @@ static int stat_seq_init(struct stat_session *session) 
		if (!stat)

			break;



		new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);

		if (!new_entry) {

			ret = -ENOMEM;

			goto exit_free_list;

		}



		new_entry->stat = stat;



		insert_stat(root, new_entry, ts->stat_cmp);

		ret = insert_stat(root, stat, ts->stat_cmp);

		if (ret)

			goto exit_free_rbtree;

	}



exit:

	mutex_unlock(&session->stat_mutex);

	return ret;



exit_free_list:

exit_free_rbtree:

	reset_stat_session(session);

	mutex_unlock(&session->stat_mutex);

	return ret;
@@ -207,7 +195,7 @@ static void *stat_seq_start(struct seq_file *s, loff_t *pos) 
	struct rb_node *node;

	int i;



	/* Prevent from tracer switch or stat_list modification */

	/* Prevent from tracer switch or rbtree modification */

	mutex_lock(&session->stat_mutex);



	/* If we are in the beginning of the file, print the headers */
@@ -280,7 +268,7 @@ static int tracing_stat_open(struct inode *inode, struct file *file) 
}



/*

 * Avoid consuming memory with our now useless list.

 * Avoid consuming memory with our now useless rbtree.

 */

static int tracing_stat_release(struct inode *i, struct file *f)

{