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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: Liming Wang <liming.wang@windriver.com>
Reviewed-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Liming Wang 2008-11-28 12:13:21 +08:00 committed by Ingo Molnar
parent c7cc773076
commit 50cdaf08a8
1 changed files with 10 additions and 17 deletions
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27
kernel/trace/ftrace.c
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@ -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;