Re: [RFC] locking: rwbase: Take care of ordering guarantee for fastpath reader

[Peter Zijlstra]

On Fri, Sep 03, 2021 at 10:50:58PM +0800, Boqun Feng wrote:
> > 	 * ordering, either is strong enough to provide ACQUIRE order
> > 	 * for the above load of @readers.
> > 	 */
> > 	rwbase_set_and_save_current_state(state);
> > 	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
> > 
> > 	while (readers) {
> > 		...
> > 		readers = atomic_read(&rwb->readers);
> 
> The above should be _acquire(), right? Pairs with the last reader
> exiting the critical section and dec ->readers to 0. If so, it
> undermines the necessity of the restructure?

This is the one that's followed by set_current_state(), no?