diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 65f4282..16de393 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -139,6 +139,8 @@
 void pipe_unlock(struct pipe_inode_info *);
 void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *);
 
+extern unsigned int pipe_max_pages;
+
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe);