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Message-ID: <871c0e19-9272-e92b-28dc-a50ae705bba8@grimberg.me>
Date:   Wed, 21 Sep 2022 11:10:58 +0300
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Subject: Re: [PATCH] nvme-pci: Set min align mask before calculating
 max_hw_sectors
Content-Language: en-US
To:     Rishabh Bhatnagar <risbhat@amazon.com>,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org
Cc:     hch@lst.de, axboe@fb.com, kbusch@kernel.org, mbacco@amazon.com
References: <20220920191932.22797-1-risbhat@amazon.com>
From:   Sagi Grimberg <sagi@grimberg.me>
In-Reply-To: <20220920191932.22797-1-risbhat@amazon.com>
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> If swiotlb is force enabled dma_max_mapping_size ends up calling
> swiotlb_max_mapping_size which takes into account the min align
> mask for the device.
> Set the min align mask for nvme driver before calling
> dma_max_mapping_size while calculating max hw sectors.

Does this fix a specific bug? if so it needs a fixes tag so it can
go to stable backports as well.

> 
> Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
> ---
>   drivers/nvme/host/pci.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 98864b853eef..30e71e41a0a2 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2834,6 +2834,8 @@ static void nvme_reset_work(struct work_struct *work)
>   		nvme_start_admin_queue(&dev->ctrl);
>   	}
>   
> +	dma_set_min_align_mask(dev->dev, NVME_CTRL_PAGE_SIZE - 1);
> +
>   	/*
>   	 * Limit the max command size to prevent iod->sg allocations going
>   	 * over a single page.
> @@ -2846,7 +2848,6 @@ static void nvme_reset_work(struct work_struct *work)
>   	 * Don't limit the IOMMU merged segment size.
>   	 */
>   	dma_set_max_seg_size(dev->dev, 0xffffffff);
> -	dma_set_min_align_mask(dev->dev, NVME_CTRL_PAGE_SIZE - 1);
>   
>   	mutex_unlock(&dev->shutdown_lock);
>