Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <b73250f3-2dd6-36da-4d69-3149959f2e67@amazon.com>
Date:   Mon, 10 Oct 2022 10:55:42 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.3.2
Subject: Re: [PATCH v2] nvme-pci: Set min align mask before calculating
 max_hw_sectors
Content-Language: en-US
From:   "Bhatnagar, Rishabh" <risbhat@amazon.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     "hch@lst.de" <hch@lst.de>, "sagi@grimberg.me" <sagi@grimberg.me>,
        "axboe@fb.com" <axboe@fb.com>,
        "kbusch@kernel.org" <kbusch@kernel.org>,
        "Bacco, Mike" <mbacco@amazon.com>,
        "Herrenschmidt, Benjamin" <benh@amazon.com>,
        "Park, SeongJae" <sjpark@amazon.com>
References: <20220929182259.22523-1-risbhat@amazon.com>
 <EB43F4D1-BFD0-408B-93E7-10643B59F766@amazon.com>
In-Reply-To: <EB43F4D1-BFD0-408B-93E7-10643B59F766@amazon.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 10/4/22 9:27 AM, Bhatnagar, Rishabh wrote:
> On 9/29/22, 11:23 AM, "Rishabh Bhatnagar" <risbhat@amazon.com> wrote:
>
>      In cases where swiotlb is enabled dma_max_mapping_size takes into
>      account the min align mask for the device. Right now the mask is
>      set after the max hw sectors are calculated which might result in
>      a request size that overflows the swiotlb buffer.
>      Set the min align mask for nvme driver before calling
>      dma_max_mapping_size while calculating max hw sectors.
>      
>      Fixes: 7637de311bd2 ("nvme-pci: limit max_hw_sectors based on the DMA max mapping size")
>      Cc: stable@vger.kernel.org
>      Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
>      ---
>       Changes in V2:
>       - Add Cc: <stable@vger.kernel.org> tag
>       - Improve the commit text
>       - Add patch version
>      
>       Changes in V1:
>       - Add fixes tag
>      
>       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);
>       
>      --
>      2.37.1
>      
>      

Hi. Any review on this patch would be much appreciated!

Thanks
Rishabh