[PATCH 3/5] blk-mq: add helper of blk_mq_global_quiesce_wait()

[Ming Lei]

On Mon, Nov 22, 2021 at 03:55:36PM +0200, Sagi Grimberg wrote:
> 
> > > > Add helper of blk_mq_global_quiesce_wait() for supporting to quiesce
> > > > queues in parallel, then we can just wait once if global quiesce wait
> > > > is allowed.
> > > 
> > > blk_mq_global_quiesce_wait() is a poor name... global is scope-less and
> > > obviously it has a scope.
> > 
> > How about blk_mq_shared_quiesce_wait()? or any suggestion?
> 
> Shared between what?

All request queues in one host-wide, both scsi and nvme has such
requirement.

> 
> Maybe if the queue has a non-blocking tagset, it can have a "quiesced"
> flag that is cleared in unquiesce? then the callers can just continue
> to iterate but will only wait the rcu grace period once.

Yeah, that is what these patches try to implement.


Thanks
Ming