diff --git a/arch/s390/hypfs/hypfs_diag0c.c b/arch/s390/hypfs/hypfs_diag0c.c
index cebf05150cc1..9c398bf0ddc6 100644
--- a/arch/s390/hypfs/hypfs_diag0c.c
+++ b/arch/s390/hypfs/hypfs_diag0c.c
@@ -54,8 +54,7 @@ static void *diag0c_store(unsigned int *count)
 	if (!cpu_vec)
 		goto fail_put_online_cpus;
 	/* Note: Diag 0c needs 8 byte alignment and real storage */
-	diag0c_data = kzalloc(sizeof(struct hypfs_diag0c_hdr) +
-			      cpu_count * sizeof(struct hypfs_diag0c_entry),
+	diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
 			      GFP_KERNEL | GFP_DMA);
 	if (!diag0c_data)
 		goto fail_kfree_cpu_vec;