1 files changed, 24 insertions, 30 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 2fc11f2e2b21..efb618fc8ffe 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -840,36 +840,6 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
         return 0;
 }
 
-/*
- *      Helper to unshare the files of the current task.
- *      We don't want to expose copy_files internals to
- *      the exec layer of the kernel.
- */
-
-int unshare_files(void)
-{
-        struct files_struct *files  = current->files;
-        struct files_struct *newf;
-        int error = 0;
-
-        BUG_ON(!files);
-
-        /* This can race but the race causes us to copy when we don't
-           need to and drop the copy */
-        if(atomic_read(&files->count) == 1)
-        {
-                atomic_inc(&files->count);
-                return 0;
-        }
-        newf = dup_fd(files, &error);
-        if (newf) {
-                task_lock(current);
-                current->files = newf;
-                task_unlock(current);
-        }
-        return error;
-}
-
 static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 {
         struct sighand_struct *sig;
@@ -1807,3 +1777,27 @@ bad_unshare_cleanup_thread:
 bad_unshare_out:
         return err;
 }
+
+/*
+ *      Helper to unshare the files of the current task.
+ *      We don't want to expose copy_files internals to
+ *      the exec layer of the kernel.
+ */
+
+int unshare_files(struct files_struct **displaced)
+{
+        struct task_struct *task = current;
+        struct files_struct *copy;
+        int error;
+
+        error = unshare_fd(CLONE_FILES, &copy);
+        if (error || !copy) {
+                *displaced = NULL;
+                return error;
+        }
+        *displaced = task->files;
+        task_lock(task);
+        task->files = copy;
+        task_unlock(task);
+        return 0;
+}