Messages in this thread Patch in this message | | | From | Fam Zheng <> | Subject | [PATCH v2 1/3] bfq: Fix the missing barrier in __bfq_entity_update_weight_prio | Date | Mon, 5 Aug 2019 14:38:05 +0800 |
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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> --- block/bfq-wf2q.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c index c9ba225081ce..05f0bf4a1144 100644 --- a/block/bfq-wf2q.c +++ b/block/bfq-wf2q.c @@ -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) { -- 2.11.0
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