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From: Amit Machhiwal <amachhiw@linux.ibm.com>
To: Thorsten Blum <blum@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
	"Ritesh Harjani (IBM)" <ritesh.list@gmail.com>,
	Shrikanth Hegde <sshegde@linux.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/sysfs: Remove redundant wait time clamps
Date: Wed, 16 Sep 2026 21:02:13 +0530	[thread overview]
Message-ID: <20260916205928.ed6f9a7e-66-amachhiw@linux.ibm.com> (raw)
In-Reply-To: <20260916151254.120629-2-blum@kernel.org>

On 2026/09/16 05:12 PM, Thorsten Blum wrote:
> The wait times are u64 and cannot be negative. Remove the redundant
> clamps.
> 
> Signed-off-by: Thorsten Blum <blum@kernel.org>
> ---
>  arch/powerpc/kernel/sysfs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> index 329c1690b5ed..2100c5e2c821 100644
> --- a/arch/powerpc/kernel/sysfs.c
> +++ b/arch/powerpc/kernel/sysfs.c
> @@ -338,7 +338,7 @@ static ssize_t show_pw20_wait_time(struct device *dev,
>  		time = pw20_wt;
>  	}
>  
> -	return sysfs_emit(buf, "%llu\n", time > 0 ? time : 0);

The time variables in both show_pw20_wait_time() and show_altivec_idle_wait_time()
are u64, so the expression time > 0 ? time : 0 is indeed a no-op for all
possible values — when time == 0 the ternary also yields 0, and negative values
are impossible by type.  The simplification is correct and removes a subtly
misleading pattern that implies a signed type.

Nit: the commit message could also mention that when time == 0, the ternary
still yields 0, making the conditional identity-preserving for all possible
inputs — not just the non-negative ones.  Strengthens the rationale a little,
but not a blocker.

Reviewed-by: Amit Machhiwal <amachhiw@linux.ibm.com>

Thanks,
Amit

> +	return sysfs_emit(buf, "%llu\n", time);
>  }
>  
>  static void set_pw20_wait_entry_bit(void *val)
> @@ -460,7 +460,7 @@ static ssize_t show_altivec_idle_wait_time(struct device *dev,
>  		time = altivec_idle_wt;
>  	}
>  
> -	return sysfs_emit(buf, "%llu\n", time > 0 ? time : 0);
> +	return sysfs_emit(buf, "%llu\n", time);
>  }
>  
>  static void set_altivec_idle_wait_entry_bit(void *val)

      reply	other threads:[~2026-09-16 15:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-16 15:12 Thorsten Blum
2026-09-16 15:32 ` Amit Machhiwal [this message]

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