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Date: Wed, 21 Feb 2024 20:09:33 -0800
From: Boqun Feng <boqun.feng@gmail.com>
To: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	George Stark <gnstark@salutedevices.com>,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH 1/4] locking/qspinlock: Fix 'wait_early' set but not used
 warning
Message-ID: <ZdbI_cFBTNKJqnFj@boqun-archlinux>
References: <20240213031656.1375951-1-longman@redhat.com>
 <20240213031656.1375951-2-longman@redhat.com>
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In-Reply-To: <20240213031656.1375951-2-longman@redhat.com>

On Mon, Feb 12, 2024 at 10:16:53PM -0500, Waiman Long wrote:
> When CONFIG_LOCK_EVENT_COUNTS is off, the wait_early variable will be
> set but not used. This is expected. Recent compilers will not generate
> wait_early code in this case.
> 
> Add the __maybe_unused attribute to wait_early for suppressing this
> W=1 warning.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202312260422.f4pK3f9m-lkp@intel.com/
> Signed-off-by: Waiman Long <longman@redhat.com>

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>

Regards,
Boqun

> ---
>  kernel/locking/qspinlock_paravirt.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
> index 6a0184e9c234..ae2b12f68b90 100644
> --- a/kernel/locking/qspinlock_paravirt.h
> +++ b/kernel/locking/qspinlock_paravirt.h
> @@ -294,8 +294,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
>  {
>  	struct pv_node *pn = (struct pv_node *)node;
>  	struct pv_node *pp = (struct pv_node *)prev;
> +	bool __maybe_unused wait_early;
>  	int loop;
> -	bool wait_early;
>  
>  	for (;;) {
>  		for (wait_early = false, loop = SPIN_THRESHOLD; loop; loop--) {
> -- 
> 2.39.3
>