Messages in this thread | | | Subject | Re: [PATCH] NVMe: do not touch sq door bell if nvmeq has been suspended | From | Sagi Grimberg <> | Date | Sun, 7 Feb 2016 15:41:53 +0200 |
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> Keith, > > Is the following solution OK? > synchronize_rcu guarantee that no queue_rq is running concurrently with device disable code. > Together with your another patch (adding blk_sync_queue), both sync/async path shall be handled correctly.
This can be acceptable I think.
> Do you think synchronize_rcu shall be added to blk_sync_queue?
Or, we'll add it to blk_mq_stop_hw_queues() and then scsi will enjoy it as well.
> diff --git a/block/blk-mq.c b/block/blk-mq.c > index 4c0622f..bfe9132 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -865,7 +865,9 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) > if (!async) { > int cpu = get_cpu(); > if (cpumask_test_cpu(cpu, hctx->cpumask)) { > + rcu_read_lock(); > __blk_mq_run_hw_queue(hctx); > + rcu_read_unlock();
I think the rcu is better folded into __blk_mq_run_hw_queue to cover all the call sites.
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