expose a low-level variant of fd_install() for binder

Similar situation to that of __alloc_fd(); do not use unless you
really have to.  You should not touch any descriptor table other
than your own; it's a sure sign of a really bad API design.

As with __alloc_fd(), you *must* use a first-class reference to
struct files_struct; something obtained by get_files_struct(some task)
(let alone direct task->files) will not do.  It must be either
current->files, or obtained by get_files_struct(current) by the
owner of that sucker and given to you.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 3855f4f..59d4fc7 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -121,6 +121,8 @@
 
 extern int __alloc_fd(struct files_struct *files,
 		      unsigned start, unsigned end, unsigned flags);
+extern void __fd_install(struct files_struct *files,
+		      unsigned int fd, struct file *file);
 
 extern struct kmem_cache *files_cachep;