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ftrace: Don't increment @pos in g_start()

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It's wrong to increment @pos in g_start(). It causes some entries
lost when reading set_graph_function, if the output of the file
is larger than PAGE_SIZE.

Reviewed-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A418738.7090401@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-06-24 09:54:00 +08:00 committed by Ingo Molnar
parent f129e965be
commit 85951842a1
1 changed files with 10 additions and 11 deletions
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21
kernel/trace/ftrace.c
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@ -2500,32 +2500,31 @@ int ftrace_graph_count;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
static void * static void *
g_next(struct seq_file *m, void *v, loff_t *pos) __g_next(struct seq_file *m, loff_t *pos)
{ {
unsigned long *array = m->private; unsigned long *array = m->private;
int index = *pos;
(*pos)++; if (*pos >= ftrace_graph_count)
if (index >= ftrace_graph_count)
return NULL; return NULL;
return &array[*pos];
}
return &array[index]; static void *
g_next(struct seq_file *m, void *v, loff_t *pos)
{
(*pos)++;
return __g_next(m, pos);
} }
static void *g_start(struct seq_file *m, loff_t *pos) static void *g_start(struct seq_file *m, loff_t *pos)
{ {
void *p = NULL;
mutex_lock(&graph_lock); mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */ /* Nothing, tell g_show to print all functions are enabled */
if (!ftrace_graph_count && !*pos) if (!ftrace_graph_count && !*pos)
return (void *)1; return (void *)1;
p = g_next(m, p, pos); return __g_next(m, pos);
return p;
} }
static void g_stop(struct seq_file *m, void *p) static void g_stop(struct seq_file *m, void *p)