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From:   Guoqing Jiang <guoqing.jiang@linux.dev>
Subject: Re: [PATCH v2 03/12] md/raid5: Move stripe_add_to_batch_list() call
 out of add_stripe_bio()
To:     Logan Gunthorpe <logang@deltatee.com>,
        linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
        Song Liu <song@kernel.org>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Stephen Bates <sbates@raithlin.com>,
        Martin Oliveira <Martin.Oliveira@eideticom.com>,
        David Sloan <David.Sloan@eideticom.com>,
        Christoph Hellwig <hch@lst.de>
References: <20220420195425.34911-1-logang@deltatee.com>
 <20220420195425.34911-4-logang@deltatee.com>
Message-ID: <fb442f7c-aa5c-96ed-05af-336f83f77da7@linux.dev>
Date:   Wed, 27 Apr 2022 09:33:06 +0800
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On 4/21/22 3:54 AM, Logan Gunthorpe wrote:
> stripe_add_to_batch_list() is better done in the loop in make_request
> instead of inside add_stripe_bio(). This is clearer and allows for
> storing the batch_head state outside the loop in a subsequent patch.
>
> The call to add_stripe_bio() in retry_aligned_read() is for read
> and batching only applies to write. So it's impossible for batching
> to happen at that call site.
>
> No functional changes intended.
>
> Signed-off-by: Logan Gunthorpe<logang@deltatee.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> ---
>   drivers/md/raid5.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index cda6857e6207..8e1ece5ce984 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -3534,8 +3534,6 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
>   	}
>   	spin_unlock_irq(&sh->stripe_lock);
>   
> -	if (stripe_can_batch(sh))
> -		stripe_add_to_batch_list(conf, sh);
>   	return 1;
>   
>    overlap:
> @@ -5955,6 +5953,9 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
>   			goto retry;
>   		}
>   
> +		if (stripe_can_batch(sh))
> +			stripe_add_to_batch_list(conf, sh);
> +
>   		if (do_flush) {
>   			set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
>   			/* we only need flush for one stripe */


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

Thanks,
Guoqing