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Message-ID: <61f8f885-3f75-4e05-37dc-b54489adaeb7@acm.org>
Date:   Mon, 8 May 2023 21:22:56 -0700
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Subject: Re: [PATCH v1] block: make the fair sharing of tag configurable
Content-Language: en-US
To:     Ed Tsai <ed.tsai@mediatek.com>, axboe@kernel.dk
Cc:     linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org, martin.petersen@oracle.com,
        stanley.chu@mediatek.com, peter.wang@mediatek.com,
        chun-hung.wu@mediatek.com, alice.chao@mediatek.com,
        powen.kao@mediatek.com, naomi.chu@mediatek.com,
        wsd_upstream@mediatek.com
References: <20230509012758.27094-1-ed.tsai@mediatek.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20230509012758.27094-1-ed.tsai@mediatek.com>
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Precedence: bulk

On 5/8/23 18:27, Ed Tsai wrote:
> diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
> index d6af9d431dc6..b8b36823f5f5 100644
> --- a/block/blk-mq-tag.c
> +++ b/block/blk-mq-tag.c
> @@ -97,6 +97,7 @@ static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
>   			    struct sbitmap_queue *bt)
>   {
>   	if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
> +			blk_queue_fair_tag_sharing(data->q) &&
>   			!hctx_may_queue(data->hctx, bt))
>   		return BLK_MQ_NO_TAG;

Has it been considered to move the blk_queue_fair_tag_sharing() call into
hctx_may_queue()? That should make this patch shorter.

> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 17d7bb875fee..e96a50265285 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -5149,6 +5149,9 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
>   	blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1);
>   	if (hba->quirks & UFSHCD_QUIRK_4KB_DMA_ALIGNMENT)
>   		blk_queue_update_dma_alignment(q, 4096 - 1);
> +
> +	blk_queue_flag_clear(QUEUE_FLAG_FAIR_TAG_SHARING, q);
> +
>   	/*
>   	 * Block runtime-pm until all consumers are added.
>   	 * Refer ufshcd_setup_links().

Please split this patch into one patch for the block layer core and another
patch for the UFS driver.

Thanks,

Bart.