diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index a5b37cc65b17..769b64394298 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2311,7 +2311,14 @@ static void ioc_timer_fn(struct timer_list *timer)
 			hwm = current_hweight_max(iocg);
 			new_hwi = hweight_after_donation(iocg, old_hwi, hwm,
 							 usage, &now);
-			if (new_hwi < hwm) {
+			/*
+			 * Donation calculation assumes hweight_after_donation
+			 * to be positive, a condition that a donor w/ hwa < 2
+			 * can't meet. Don't bother with donation if hwa is
+			 * below 2. It's not gonna make a meaningful difference
+			 * anyway.
+			 */
+			if (new_hwi < hwm && hwa >= 2) {
 				iocg->hweight_donating = hwa;
 				iocg->hweight_after_donation = new_hwi;
 				list_add(&iocg->surplus_list, &surpluses);