diff --git a/drivers/char/diag/diagmem.c b/drivers/char/diag/diagmem.c
index 92e01724c313..fc926836c880 100644
--- a/drivers/char/diag/diagmem.c
+++ b/drivers/char/diag/diagmem.c
@@ -181,7 +181,7 @@ void *diagmem_alloc(struct diagchar_dev *driver, int size, int pool_type)
 			break;
 		}
 		if (size == 0 || size > mempool->itemsize ||
-			size > (int)mempool->pool->pool_data) {
+			size > (size_t)mempool->pool->pool_data) {
 			pr_err_ratelimited("diag: cannot alloc from mempool %s, invalid size: %d\n",
 					   mempool->name, size);
 			break;