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Message-ID: <1a683059-d718-9536-e8fe-d7d47e25e935@opensource.wdc.com>
Date:   Sat, 21 May 2022 08:34:03 +0900
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Subject: Re: [PATCH 4/4] libata-scsi: Cap ata_device->max_sectors according to
 shost->max_sectors
Content-Language: en-US
To:     John Garry <john.garry@huawei.com>, joro@8bytes.org,
        will@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com,
        hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com
Cc:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-ide@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-scsi@vger.kernel.org, liyihang6@hisilicon.com,
        chenxiang66@hisilicon.com, thunder.leizhen@huawei.com
References: <1653035003-70312-1-git-send-email-john.garry@huawei.com>
 <1653035003-70312-5-git-send-email-john.garry@huawei.com>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <1653035003-70312-5-git-send-email-john.garry@huawei.com>
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Precedence: bulk

On 5/20/22 17:23, John Garry wrote:
> ATA devices (struct ata_device) have a max_sectors field which is
> configured internally in libata. This is then used to (re)configure the
> associated sdev request queue max_sectors value from how it is earlier set
> in __scsi_init_queue(). In __scsi_init_queue() the max_sectors value is set
> according to shost limits, which includes host DMA mapping limits.
> 
> Cap the ata_device max_sectors according to shost->max_sectors to respect
> this shost limit.
> 
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
>  drivers/ata/libata-scsi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 06c9d90238d9..25fe89791641 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -1036,6 +1036,7 @@ int ata_scsi_dev_config(struct scsi_device *sdev, struct ata_device *dev)
>  		dev->flags |= ATA_DFLAG_NO_UNLOAD;
>  
>  	/* configure max sectors */
> +	dev->max_sectors = min(dev->max_sectors, sdev->host->max_sectors);
>  	blk_queue_max_hw_sectors(q, dev->max_sectors);
>  
>  	if (dev->class == ATA_DEV_ATAPI) {

Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

-- 
Damien Le Moal
Western Digital Research