On Tue, Nov 23, 2021 at 11:58:42AM -0700, Jens Axboe wrote:
> On 11/23/21 11:50 AM, Christoph Hellwig wrote:
> >> + spin_lock_irq(&q->stats->lock);
> >> + if (q->poll_stat) {
> >> + spin_unlock_irq(&q->stats->lock);
> >> + kfree(poll_stat);
> >> + return true;
> >> + }
> >> + q->poll_stat = poll_stat;
> >> + spin_unlock_irq(&q->stats->lock);
> >
> > If we'd use a cmpxchg to install the pointer we could keep the
> > blk_queue_stats definition private.
>
> How about we just move this alloc+enable logic into blk-stat.c instead?
That's a good idea either way. But I think cmpxchg is much better
for installing a pointer than an unrelated lock.
