linux-kernel - Re: [PATCH] percpu_ref: Don't opencode percpu_ref_is

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Date:   Tue, 11 May 2021 13:49:23 +0000
From:   Dennis Zhou <dennis@...nel.org>
To:     Nikolay Borisov <nborisov@...e.com>
Cc:     tj@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] percpu_ref: Don't opencode percpu_ref_is_dying

Hello,

On Tue, May 11, 2021 at 04:16:33PM +0300, Nikolay Borisov wrote:
> Signed-off-by: Nikolay Borisov <nborisov@...e.com>
> ---
>  lib/percpu-refcount.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
> index a1071cdefb5a..af9302141bcf 100644
> --- a/lib/percpu-refcount.c
> +++ b/lib/percpu-refcount.c
> @@ -275,7 +275,7 @@ static void __percpu_ref_switch_mode(struct percpu_ref *ref,
>  	wait_event_lock_irq(percpu_ref_switch_waitq, !data->confirm_switch,
>  			    percpu_ref_switch_lock);
>  
> -	if (data->force_atomic || (ref->percpu_count_ptr & __PERCPU_REF_DEAD))
> +	if (data->force_atomic || percpu_ref_is_dying(ref))
>  		__percpu_ref_switch_to_atomic(ref, confirm_switch);
>  	else
>  		__percpu_ref_switch_to_percpu(ref);
> @@ -385,7 +385,7 @@ void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
>  
>  	spin_lock_irqsave(&percpu_ref_switch_lock, flags);
>  
> -	WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_DEAD,
> +	WARN_ONCE(percpu_ref_is_dying(ref),
>  		  "%s called more than once on %ps!", __func__,
>  		  ref->data->release);
>  
> @@ -465,7 +465,7 @@ void percpu_ref_resurrect(struct percpu_ref *ref)
>  
>  	spin_lock_irqsave(&percpu_ref_switch_lock, flags);
>  
> -	WARN_ON_ONCE(!(ref->percpu_count_ptr & __PERCPU_REF_DEAD));
> +	WARN_ON_ONCE(!percpu_ref_is_dying(ref));
>  	WARN_ON_ONCE(__ref_is_percpu(ref, &percpu_count));
>  
>  	ref->percpu_count_ptr &= ~__PERCPU_REF_DEAD;
> -- 
> 2.25.1
> 

If no one has any objections to me officially taking percpu_ref, I'll
pick this up.

Thanks,
Dennis