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bfq: Fix the missing barrier in __bfq_entity_update_weight_prio

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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>
Reviewed-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Fam Zheng 2019-08-28 11:54:51 +08:00 committed by Jens Axboe
parent a26142559c
commit e9d3c866bf
1 changed files with 2 additions and 0 deletions
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block/bfq-wf2q.c
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@ -744,6 +744,8 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
} }
#endif #endif
/* Matches the smp_wmb() in bfq_group_set_weight. */
smp_rmb();
old_st->wsum -= entity->weight; old_st->wsum -= entity->weight;
if (entity->new_weight != entity->orig_weight) { if (entity->new_weight != entity->orig_weight) {