From mboxrd@z Thu Jan  1 00:00:00 1970
From: bvanassche@acm.org (Bart Van Assche)
Date: Tue, 19 Mar 2019 08:10:22 -0700
Subject: [PATCH 0/8]: blk-mq: use static_rqs to iterate busy tags
In-Reply-To: <3cd58454-eda3-de9a-0eed-b6a7edbce28f@oracle.com>
References: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com>
 <1552930085.152266.36.camel@acm.org>
 <3cd58454-eda3-de9a-0eed-b6a7edbce28f@oracle.com>
Message-ID: <1553008222.152266.43.camel@acm.org>

On Tue, 2019-03-19@09:25 +0800, jianchao.wang wrote:
> Do you mean this patch from Jens ?
> https://marc.info/?l=linux-block&m=154534605914798&w=2
> 
> +	rcu_read_lock();
>  	sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
> +	rcu_read_unlock();
> 
> The busy_iter_fn could sleep for nvme
> blk_mq_check_expired
>   -> blk_mq_rq_timed_out
>     -> q->mq_ops->timeout
>        nvme_timeout
>          -> nvme_dev_disable
>             -> mutex_lock dev->shutdown_lock

Hi Jianchao,

I think that's an additional reason to rewrite NVMe error handling ...

Best regards,

Bart.