Messages in this thread | | | Date | Thu, 6 Jul 2023 11:13:07 -0700 | Subject | Re: [PATCH RFC 4/7] blk-mq: precalculate available tags for hctx_may_queue() | From | Bart Van Assche <> |
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On 6/18/23 09:07, Yu Kuai wrote: > +static void blk_mq_update_available_driver_tags(struct blk_mq_hw_ctx *hctx) > +{ > + struct blk_mq_tags *tags = hctx->tags; > + unsigned int nr_tags; > + struct tag_sharing *tag_sharing; > + > + if (tags->ctl.share_queues <= 1) > + nr_tags = tags->nr_tags; > + else > + nr_tags = max((tags->nr_tags + tags->ctl.share_queues - 1) / > + tags->ctl.share_queues, 4U); > + > + list_for_each_entry(tag_sharing, &tags->ctl.head, node) > + tag_sharing->available_tags = nr_tags; > +}
Since READ_ONCE() is used to read the available_tags member, WRITE_ONCE() should be used to update that member, even if a spinlock is held around the update.
Thanks,
Bart.
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