fs/namespace.c: path_is_under can be boolean

This patch makes path_is_under return bool to improve
readability due to this particular function only using either
one or zero as its return value.

No functional change.

Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 0570729..b27156f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2939,9 +2939,9 @@
 	return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry);
 }
 
-int path_is_under(struct path *path1, struct path *path2)
+bool path_is_under(struct path *path1, struct path *path2)
 {
-	int res;
+	bool res;
 	read_seqlock_excl(&mount_lock);
 	res = is_path_reachable(real_mount(path1->mnt), path1->dentry, path2);
 	read_sequnlock_excl(&mount_lock);