Re: [PATCH v2] nvme-pci: Set min align mask before calculating max_hw_sectors

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