1 files changed, 17 insertions, 15 deletions

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index be682b62fe58..fde3be15c642 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -107,8 +107,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
         if (unlikely(!ftrace_enabled || stack_trace_disabled))
                 return;
 
-        resched = need_resched();
-        preempt_disable_notrace();
+        resched = ftrace_preempt_disable();
 
         cpu = raw_smp_processor_id();
         /* no atomic needed, we only modify this variable by this cpu */
@@ -120,10 +119,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
  out:
         per_cpu(trace_active, cpu)--;
         /* prevent recursion in schedule */
-        if (resched)
-                preempt_enable_no_resched_notrace();
-        else
-                preempt_enable_notrace();
+        ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_ops __read_mostly =
@@ -184,11 +180,16 @@ static struct file_operations stack_max_size_fops = {
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-        long i = (long)m->private;
+        long i;
 
         (*pos)++;
 
-        i++;
+        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)
@@ -201,12 +202,15 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-        void *t = &m->private;
+        void *t = SEQ_START_TOKEN;
         loff_t l = 0;
 
         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))
                 ;
 
@@ -235,10 +239,10 @@ static int trace_lookup_stack(struct seq_file *m, long i)
 
 static int t_show(struct seq_file *m, void *v)
 {
-        long i = *(long *)v;
+        long i;
         int size;
 
-        if (i < 0) {
+        if (v == SEQ_START_TOKEN) {
                 seq_printf(m, "        Depth   Size      Location"
                            "    (%d entries)\n"
                            "        -----   ----      --------\n",
@@ -246,6 +250,8 @@ static int t_show(struct seq_file *m, void *v)
                 return 0;
         }
 
+        i = *(long *)v;
+
         if (i >= max_stack_trace.nr_entries ||
             stack_dump_trace[i] == ULONG_MAX)
                 return 0;
@@ -275,10 +281,6 @@ static int stack_trace_open(struct inode *inode, struct file *file)
         int ret;
 
         ret = seq_open(file, &stack_trace_seq_ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-                m->private = (void *)-1;
-        }
 
         return ret;
 }