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Date:   Wed, 2 Mar 2022 00:24:34 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        Yu Kuai <yukuai3@huawei.com>
Subject: Re: [PATCH 6/6] blk-mq: manage hctx map via xarray
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On Wed, Mar 02, 2022 at 10:06:04AM +0800, Ming Lei wrote:
> I did considered xa_for_each(), but it requires rcu read lock.

No, I doesn't.  It just takes a RCU lock internally.

> Also queue_for_each_hw_ctx() is supposed to not run in fast path,
> meantime xa_load() is lightweight enough too, so repeated xa_load()
> is fine here.

I'd rather have the clarity of the proper iterators.