linux-kernel - Re: [PATCH v2 2/4] powerpc/interrupt: Refactor prep_irq_for_user

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Message-Id: <1623378421.ayihg84s3a.astroid@bobo.none>
Date:   Fri, 11 Jun 2021 12:30:31 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2 2/4] powerpc/interrupt: Refactor
 prep_irq_for_user_exit()

Excerpts from Christophe Leroy's message of June 5, 2021 12:56 am:
> prep_irq_for_user_exit() is a superset of
> prep_irq_for_kernel_enabled_exit().
> 
> Refactor it.

I like the refactoring, but now prep_irq_for_user_exit() is calling 
prep_irq_for_kernel_enabled_exit(), which seems like the wrong naming.

You could re-name prep_irq_for_kernel_enabled_exit() to
prep_irq_for_enabled_exit() maybe? Or it could be 
__prep_irq_for_enabled_exit() then prep_irq_for_kernel_enabled_exit()
and prep_irq_for_user_exit() would both call it.

Otherwise

Reviewed-by: Nicholas Piggin <npiggin@...il.com>

> 
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
>  arch/powerpc/kernel/interrupt.c | 25 +++++--------------------
>  1 file changed, 5 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
> index 539455c62c5b..b6aa80930733 100644
> --- a/arch/powerpc/kernel/interrupt.c
> +++ b/arch/powerpc/kernel/interrupt.c
> @@ -78,29 +78,14 @@ static notrace __always_inline bool prep_irq_for_kernel_enabled_exit(bool restar
>   */
>  static notrace __always_inline bool prep_irq_for_user_exit(void)
>  {
> -	user_enter_irqoff();
> -	/* This must be done with RI=1 because tracing may touch vmaps */
> -	trace_hardirqs_on();
> -
> -#ifdef CONFIG_PPC32
> -	__hard_EE_RI_disable();
> -#else
> -	if (exit_must_hard_disable())
> -		__hard_EE_RI_disable();
> +	bool ret;
>  
> -	/* This pattern matches prep_irq_for_idle */
> -	if (unlikely(lazy_irq_pending_nocheck())) {
> -		if (exit_must_hard_disable()) {
> -			local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
> -			__hard_RI_enable();
> -		}
> -		trace_hardirqs_off();
> +	user_enter_irqoff();
> +	ret = prep_irq_for_kernel_enabled_exit(true);
> +	if (!ret)
>  		user_exit_irqoff();
>  
> -		return false;
> -	}
> -#endif
> -	return true;
> +	return ret;
>  }
>  
>  /* Has to run notrace because it is entered not completely "reconciled" */
> -- 
> 2.25.0
> 
>