trace_stack: Simplify seqfile code

Extract duplicate code in t_start() and t_next().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A891A91.4030602@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 0da1cff..0f6facb 100644 (file)
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -186,43 +186,33 @@ static const struct file_operations stack_max_size_fops = {
 };
 
 static void *
-t_next(struct seq_file *m, void *v, loff_t *pos)
+__next(struct seq_file *m, loff_t *pos)
 {
-       long i;
+       long n = *pos - 1;
 
-       (*pos)++;
-
-       if (v == SEQ_START_TOKEN)
-               i = 0;
-       else {
-               i = *(long *)v;
-               i++;
-       }
-
-       if (i >= max_stack_trace.nr_entries ||
-           stack_dump_trace[i] == ULONG_MAX)
+       if (n >= max_stack_trace.nr_entries || stack_dump_trace[n] == ULONG_MAX)
                return NULL;
 
-       m->private = (void *)i;
-
+       m->private = (void *)n;
        return &m->private;
 }
 
-static void *t_start(struct seq_file *m, loff_t *pos)
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       void *t = SEQ_START_TOKEN;
-       loff_t l = 0;
+       (*pos)++;
+       return __next(m, pos);
+}
 
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
        local_irq_disable();
        __raw_spin_lock(&max_stack_lock);
 
        if (*pos == 0)
                return SEQ_START_TOKEN;
 
-       for (; t && l < *pos; t = t_next(m, t, &l))
-               ;
-
-       return t;
+       return __next(m, pos);
 }
 
 static void t_stop(struct seq_file *m, void *p)