1 files changed, 45 insertions, 53 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7d854290bf81..898f868833f2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -826,59 +826,33 @@ enum {
 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 {
         struct ftrace_event_call *call = m->private;
-        struct ftrace_event_field *field;
         struct list_head *common_head = &ftrace_common_fields;
         struct list_head *head = trace_get_fields(call);
+        struct list_head *node = v;
 
         (*pos)++;
 
         switch ((unsigned long)v) {
         case FORMAT_HEADER:
-                if (unlikely(list_empty(common_head)))
-                        return NULL;
-
-                field = list_entry(common_head->prev,
-                                   struct ftrace_event_field, link);
-                return field;
+                node = common_head;
+                break;
 
         case FORMAT_FIELD_SEPERATOR:
-                if (unlikely(list_empty(head)))
-                        return NULL;
-
-                field = list_entry(head->prev, struct ftrace_event_field, link);
-                return field;
+                node = head;
+                break;
 
         case FORMAT_PRINTFMT:
                 /* all done */
                 return NULL;
         }
 
-        field = v;
-        if (field->link.prev == common_head)
+        node = node->prev;
+        if (node == common_head)
                 return (void *)FORMAT_FIELD_SEPERATOR;
-        else if (field->link.prev == head)
+        else if (node == head)
                 return (void *)FORMAT_PRINTFMT;
-
-        field = list_entry(field->link.prev, struct ftrace_event_field, link);
-
-        return field;
-}
-
-static void *f_start(struct seq_file *m, loff_t *pos)
-{
-        loff_t l = 0;
-        void *p;
-
-        /* Start by showing the header */
-        if (!*pos)
-                return (void *)FORMAT_HEADER;
-
-        p = (void *)FORMAT_HEADER;
-        do {
-                p = f_next(m, p, &l);
-        } while (p && l < *pos);
-
-        return p;
+        else
+                return node;
 }
 
 static int f_show(struct seq_file *m, void *v)
@@ -904,8 +878,7 @@ static int f_show(struct seq_file *m, void *v)
                 return 0;
         }
 
-        field = v;
-
+        field = list_entry(v, struct ftrace_event_field, link);
         /*
          * Smartly shows the array type(except dynamic array).
          * Normal:
@@ -932,6 +905,17 @@ static int f_show(struct seq_file *m, void *v)
         return 0;
 }
 
+static void *f_start(struct seq_file *m, loff_t *pos)
+{
+        void *p = (void *)FORMAT_HEADER;
+        loff_t l = 0;
+
+        while (l < *pos && p)
+                p = f_next(m, p, &l);
+
+        return p;
+}
+
 static void f_stop(struct seq_file *m, void *p)
 {
 }
@@ -963,23 +947,14 @@ static ssize_t
 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
         struct ftrace_event_call *call = filp->private_data;
-        struct trace_seq *s;
-        int r;
+        char buf[32];
+        int len;
 
         if (*ppos)
                 return 0;
 
-        s = kmalloc(sizeof(*s), GFP_KERNEL);
-        if (!s)
-                return -ENOMEM;
-
-        trace_seq_init(s);
-        trace_seq_printf(s, "%d\n", call->event.type);
-
-        r = simple_read_from_buffer(ubuf, cnt, ppos,
-                                    s->buffer, s->len);
-        kfree(s);
-        return r;
+        len = sprintf(buf, "%d\n", call->event.type);
+        return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
 }
 
 static ssize_t
@@ -1218,6 +1193,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 
 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_open(struct inode *inode, struct file *file);
+static int ftrace_event_release(struct inode *inode, struct file *file);
 
 static const struct seq_operations show_event_seq_ops = {
         .start = t_start,
@@ -1245,7 +1221,7 @@ static const struct file_operations ftrace_set_event_fops = {
         .read = seq_read,
         .write = ftrace_event_write,
         .llseek = seq_lseek,
-        .release = seq_release,
+        .release = ftrace_event_release,
 };
 
 static const struct file_operations ftrace_enable_fops = {
@@ -1323,6 +1299,15 @@ ftrace_event_open(struct inode *inode, struct file *file,
         return ret;
 }
 
+static int ftrace_event_release(struct inode *inode, struct file *file)
+{
+        struct trace_array *tr = inode->i_private;
+
+        trace_array_put(tr);
+
+        return seq_release(inode, file);
+}
+
 static int
 ftrace_event_avail_open(struct inode *inode, struct file *file)
 {
@@ -1336,12 +1321,19 @@ ftrace_event_set_open(struct inode *inode, struct file *file)
 {
         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
         struct trace_array *tr = inode->i_private;
+        int ret;
+
+        if (trace_array_get(tr) < 0)
+                return -ENODEV;
 
         if ((file->f_mode & FMODE_WRITE) &&
             (file->f_flags & O_TRUNC))
                 ftrace_clear_events(tr);
 
-        return ftrace_event_open(inode, file, seq_ops);
+        ret = ftrace_event_open(inode, file, seq_ops);
+        if (ret < 0)
+                trace_array_put(tr);
+        return ret;
 }
 
 static struct event_subsystem *