[PATCH 5/8] blk-mq: add tagset quiesce interface

[Bart Van Assche]

On 10/20/22 03:56, Christoph Hellwig wrote:
> From: Chao Leng <lengchao at huawei.com>
> 
> Drivers that have shared tagsets may need to quiesce potentially a lot
> of request queues that all share a single tagset (e.g. nvme). Add an
> interface to quiesce all the queues on a given tagset. This interface is
> useful because it can speedup the quiesce by doing it in parallel.
> 
> Because some queues should not need to be quiesced(e.g. nvme connect_q)

should not need -> do not have

> when quiesce the tagset. So introduce QUEUE_FLAG_SKIP_TAGSET_QUIESCE to

quiesce -> quiescing

. So -> ,

> tagset quiesce interface to skip the queue.

Hi Christoph,

Are there any drivers that may call blk_mq_quiesce_tagset() concurrently 
from two different threads? blk_mq_quiesce_queue() supports this but 
blk_mq_quiesce_tagset() cannot support this because of the mechanism 
used to mark request queues that should be skipped (queue flag).

Thanks,

Bart.