new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 0c80d3f..7083295 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -281,7 +281,7 @@
 
 static inline struct hstate *hstate_file(struct file *f)
 {
-	return hstate_inode(f->f_dentry->d_inode);
+	return hstate_inode(file_inode(f));
 }
 
 static inline struct hstate *hstate_vma(struct vm_area_struct *vma)