[PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce

[Ming Lei]

On Tue, Oct 12, 2021 at 12:30:10PM +0200, Christoph Hellwig wrote:
> On Sat, Oct 09, 2021 at 11:47:13AM +0800, Ming Lei wrote:
> > +	spin_lock_irqsave(&q->queue_lock, flags);
> > +	if (!q->quiesce_depth++)
> > +		blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
> 
> We can get rid of the QUEUE_FLAG_QUIESCED flag now and just look
> at ->quiesce_depth directly.

I'd rather not to do that given we need to check QUEUE_FLAG_QUIESCED in fast
path.

> 
> > +	spin_lock_irqsave(&q->queue_lock, flags);
> > +	WARN_ON_ONCE(q->quiesce_depth <= 0);
> > +	if (q->quiesce_depth > 0 && !--q->quiesce_depth) {
> 
> 	if (WARN_ON_ONCE(q->quiesce_depth <= 0))
> 		; /* oops */
> 	else if (!--q->quiesce_depth)
> 		run_queue = true;

OK.


Thanks,
Ming