[PATCH] sanitize __user_walk_fd() et.al.

* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
	user_path_at(dfd, pathname, flags, &path)
	user_path(pathname, &path)
	user_lpath(pathname, &path)
	user_path_dir(pathname, &path)  (fail if not a directory)
  The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 60e35a0..00888ff 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -54,12 +54,13 @@
 #define LOOKUP_OPEN		(0x0100)
 #define LOOKUP_CREATE		(0x0200)
 
-extern int __user_walk(const char __user *, unsigned, struct nameidata *);
-extern int __user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *);
-#define user_path_walk(name,nd) \
-	__user_walk_fd(AT_FDCWD, name, LOOKUP_FOLLOW, nd)
-#define user_path_walk_link(name,nd) \
-	__user_walk_fd(AT_FDCWD, name, 0, nd)
+extern int user_path_at(int, const char __user *, unsigned, struct path *);
+
+#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
+#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
+#define user_path_dir(name, path) \
+	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
+
 extern int path_lookup(const char *, unsigned, struct nameidata *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct nameidata *);