Commit e9d3c866 authored Aug 28, 2019 by Fam Zheng Committed by Jens Axboe Sep 06, 2019

bfq: Fix the missing barrier in __bfq_entity_update_weight_prio



The comment of bfq_group_set_weight says the reading of prio_changed
should happen before the reading of weight, but a memory barrier is
missing here. Add it now, to match the smp_wmb() there.

Signed-off-by: Fam Zheng <zhengfeiran@bytedance.com>
Reviewed-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent a2614255

block/bfq-wf2q.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -744,6 +744,8 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
		}
		#endif

		/* Matches the smp_wmb() in bfq_group_set_weight. */
		smp_rmb();
		old_st->wsum -= entity->weight;

		if (entity->new_weight != entity->orig_weight) {