diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 7077521..27cebf1 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -265,7 +265,7 @@
 
 	return -EINVAL;
 #else
-	VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);
+	VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
 
 	if (rw == READ)
 		return nfs_file_direct_read(iocb, iter, pos);