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Date:   Mon, 16 Jul 2018 17:37:27 -0700
From:   Shaohua Li <shli@kernel.org>
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     linux-kernel@vger.kernel.org, tglx@linutronix.de,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Anna-Maria Gleixner <anna-maria@linutronix.de>,
        linux-raid@vger.kernel.org
Subject: Re: [PATCH 1/6] drivers/md/raid5: Use irqsave variant of
 atomic_dec_and_lock()
Message-ID: <20180717003727.GA128433@kernel.org>
References: <20180703200141.28415-1-bigeasy@linutronix.de>
 <20180703200141.28415-2-bigeasy@linutronix.de>
 <20180716122740.q7oim7te5bybcniz@linutronix.de>
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On Mon, Jul 16, 2018 at 02:27:40PM +0200, Sebastian Andrzej Siewior wrote:
> On 2018-07-03 22:01:36 [+0200], To linux-kernel@vger.kernel.org wrote:
> > From: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > 
> > The irqsave variant of atomic_dec_and_lock handles irqsave/restore when
> > taking/releasing the spin lock. With this variant the call of
> > local_irq_save is no longer required.
> 
> Shaohua, are you with this?

Acked-by: Shaohua Li <shli@kernel.org> 
> > Cc: Shaohua Li <shli@kernel.org>
> > Cc: linux-raid@vger.kernel.org
> > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > ---
> >  drivers/md/raid5.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> > index 2031506a0ecd..e933bff9459e 100644
> > --- a/drivers/md/raid5.c
> > +++ b/drivers/md/raid5.c
> > @@ -409,16 +409,15 @@ void raid5_release_stripe(struct stripe_head *sh)
> >  		md_wakeup_thread(conf->mddev->thread);
> >  	return;
> >  slow_path:
> > -	local_irq_save(flags);
> >  	/* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
> > -	if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
> > +	if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
> >  		INIT_LIST_HEAD(&list);
> >  		hash = sh->hash_lock_index;
> >  		do_release_stripe(conf, sh, &list);
> >  		spin_unlock(&conf->device_lock);
> >  		release_inactive_stripe_list(conf, &list, hash);
> > +		local_irq_restore(flags);
> >  	}
> > -	local_irq_restore(flags);
> >  }
> >  
> >  static inline void remove_hash(struct stripe_head *sh)
> > -- 
> > 2.18.0
> >