debugfs: fix race in u32_array_read and allocate array at open

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / debugfs / file.c

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 2340f69..a09d3c0 100644 (file)
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -526,12 +526,6 @@ struct array_data {
        u32 elements;
 };
 
-static int u32_array_open(struct inode *inode, struct file *file)
-{
-       file->private_data = NULL;
-       return nonseekable_open(inode, file);
-}
-
 static size_t format_array(char *buf, size_t bufsize, const char *fmt,
                           u32 *array, u32 array_size)
 {
@@ -573,26 +567,21 @@ static char *format_array_alloc(const char *fmt, u32 *array,
        return ret;
 }
 
-static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
-                             loff_t *ppos)
+static int u32_array_open(struct inode *inode, struct file *file)
 {
-       struct inode *inode = file->f_path.dentry->d_inode;
        struct array_data *data = inode->i_private;
-       size_t size;
 
-       if (*ppos == 0) {
-               if (file->private_data) {
-                       kfree(file->private_data);
-                       file->private_data = NULL;
-               }
-
-               file->private_data = format_array_alloc("%u", data->array,
-                                                             data->elements);
-       }
+       file->private_data = format_array_alloc("%u", data->array,
+                                                     data->elements);
+       if (!file->private_data)
+               return -ENOMEM;
+       return nonseekable_open(inode, file);
+}
 
-       size = 0;
-       if (file->private_data)
-               size = strlen(file->private_data);
+static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
+                             loff_t *ppos)
+{
+       size_t size = strlen(file->private_data);
 
        return simple_read_from_buffer(buf, len, ppos,
                                        file->private_data, size);