Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 50cdaf08 authored by Liming Wang's avatar Liming Wang Committed by Ingo Molnar
Browse files

ftrace: improve seq_operation of ftrace 



Impact: make ftrace position computing more sane

First remove useless ->pos field. Then we needn't check seq_printf
in .show like other place.

Signed-off-by: default avatarLiming Wang <liming.wang@windriver.com>
Reviewed-by: default avatarBruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c7cc7730

kernel/trace/ftrace.c

+10 −17
Original line number Diff line number Diff line
@@ -786,7 +786,6 @@ enum { 
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */



struct ftrace_iterator {

	loff_t			pos;

	struct ftrace_page	*pg;

	unsigned		idx;

	unsigned		flags;
@@ -811,6 +810,8 @@ t_next(struct seq_file *m, void *v, loff_t *pos) 
			iter->pg = iter->pg->next;

			iter->idx = 0;

			goto retry;

		} else {

			iter->idx = -1;

		}

	} else {

		rec = &iter->pg->records[iter->idx++];
@@ -833,8 +834,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos) 
	}

	spin_unlock(&ftrace_lock);



	iter->pos = *pos;



	return rec;

}
@@ -842,13 +841,15 @@ static void *t_start(struct seq_file *m, loff_t *pos) 
{

	struct ftrace_iterator *iter = m->private;

	void *p = NULL;

	loff_t l = -1;



	if (*pos > iter->pos)

		*pos = iter->pos;

	if (*pos > 0) {

		if (iter->idx < 0)

			return p;

		(*pos)--;

		iter->idx--;

	}



	l = *pos;

	p = t_next(m, p, &l);

	p = t_next(m, p, pos);



	return p;

}
@@ -859,21 +860,15 @@ static void t_stop(struct seq_file *m, void *p) 


static int t_show(struct seq_file *m, void *v)

{

	struct ftrace_iterator *iter = m->private;

	struct dyn_ftrace *rec = v;

	char str[KSYM_SYMBOL_LEN];

	int ret = 0;



	if (!rec)

		return 0;



	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);



	ret = seq_printf(m, "%s\n", str);

	if (ret < 0) {

		iter->pos--;

		iter->idx--;

	}

	seq_printf(m, "%s\n", str);



	return 0;

}
@@ -899,7 +894,6 @@ ftrace_avail_open(struct inode *inode, struct file *file) 
		return -ENOMEM;



	iter->pg = ftrace_pages_start;

	iter->pos = 0;



	ret = seq_open(file, &show_ftrace_seq_ops);

	if (!ret) {
@@ -986,7 +980,6 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable) 


	if (file->f_mode & FMODE_READ) {

		iter->pg = ftrace_pages_start;

		iter->pos = 0;

		iter->flags = enable ? FTRACE_ITER_FILTER :

			FTRACE_ITER_NOTRACE;