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Subject: Re: [PATCH v3 2/5] md/raid10: don't modify 'nr_waitng' in
 wait_barrier() for the case nowait
To:     Yu Kuai <yukuai1@huaweicloud.com>, song@kernel.org,
        logang@deltatee.com, pmenzel@molgen.mpg.de
Cc:     linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
        yukuai3@huawei.com, yi.zhang@huawei.com
References: <20220916113428.774061-1-yukuai1@huaweicloud.com>
 <20220916113428.774061-3-yukuai1@huaweicloud.com>
From:   Guoqing Jiang <guoqing.jiang@linux.dev>
Message-ID: <fbf58ad3-2eff-06df-6426-3b4629408e94@linux.dev>
Date:   Sun, 18 Sep 2022 19:40:04 +0800
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On 9/16/22 7:34 PM, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> For the case nowait in wait_barrier(), there is no point to increase
> nr_waiting and then decrease it.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>   drivers/md/raid10.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 37fd9284054e..df435d693637 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -990,17 +990,17 @@ static bool wait_barrier(struct r10conf *conf, bool nowait)
>   
>   	spin_lock_irq(&conf->resync_lock);
>   	if (conf->barrier) {
> -		conf->nr_waiting++;
>   		/* Return false when nowait flag is set */
>   		if (nowait) {
>   			ret = false;
>   		} else {
> +			conf->nr_waiting++;
>   			raid10_log(conf->mddev, "wait barrier");
>   			wait_event_lock_irq(conf->wait_barrier,
>   					    stop_waiting_barrier(conf),
>   					    conf->resync_lock);
> +			conf->nr_waiting--;
>   		}
> -		conf->nr_waiting--;
>   		if (!conf->nr_waiting)
>   			wake_up(&conf->wait_barrier);
>   	}

Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>

Thanks,
Guoqing