link_path_walk: nd->depth massage, part 3

remove decrement/increment surrounding nd_alloc_stack(), adjust the
test in it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -539,7 +539,7 @@ static int __nd_alloc_stack(struct nameidata *nd)
 
 static inline int nd_alloc_stack(struct nameidata *nd)
 {
-	if (likely(nd->depth != EMBEDDED_LEVELS - 1))
+	if (likely(nd->depth != EMBEDDED_LEVELS))
 		return 0;
 	if (likely(nd->stack != nd->internal))
 		return 0;
@@ -1824,9 +1824,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 		if (err) {
 			const char *s;
 
-			nd->depth--;
 			err = nd_alloc_stack(nd);
-			nd->depth++;
 			if (unlikely(err)) {
 				path_to_nameidata(&nd->link, nd);
 				break;