* [PATCH] fpga: dfl: pci: Remove useless DMA-32 fallback configuration
@ 2022-03-18 0:59 cgel.zte
2022-03-18 10:34 ` Xu Yilun
0 siblings, 1 reply; 2+ messages in thread
From: cgel.zte @ 2022-03-18 0:59 UTC (permalink / raw)
To: hao.wu; +Cc: trix, linux-fpga, linux-kernel, Minghao Chi, Zeal Robot
From: Minghao Chi <chi.minghao@zte.com.cn>
As stated in [1], dma_set_mask() with a 64-bit mask will never fail if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.
Simplify code and remove some dead code accordingly.
[1]: https://lkml.org/lkml/2021/6/7/398
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
---
drivers/fpga/dfl-pci.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
index 717ac9715970..42fdfa7a28d6 100644
--- a/drivers/fpga/dfl-pci.c
+++ b/drivers/fpga/dfl-pci.c
@@ -356,8 +356,6 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
pci_set_master(pcidev);
ret = dma_set_mask_and_coherent(&pcidev->dev, DMA_BIT_MASK(64));
- if (ret)
- ret = dma_set_mask_and_coherent(&pcidev->dev, DMA_BIT_MASK(32));
if (ret) {
dev_err(&pcidev->dev, "No suitable DMA support available.\n");
goto disable_error_report_exit;
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] fpga: dfl: pci: Remove useless DMA-32 fallback configuration
2022-03-18 0:59 [PATCH] fpga: dfl: pci: Remove useless DMA-32 fallback configuration cgel.zte
@ 2022-03-18 10:34 ` Xu Yilun
0 siblings, 0 replies; 2+ messages in thread
From: Xu Yilun @ 2022-03-18 10:34 UTC (permalink / raw)
To: cgel.zte; +Cc: hao.wu, trix, linux-fpga, linux-kernel, Minghao Chi, Zeal Robot
On Fri, Mar 18, 2022 at 12:59:38AM +0000, cgel.zte@gmail.com wrote:
> From: Minghao Chi <chi.minghao@zte.com.cn>
>
> As stated in [1], dma_set_mask() with a 64-bit mask will never fail if
> dev->dma_mask is non-NULL.
> So, if it fails, the 32 bits case will also fail for the same reason.
The code change is good to me, but maybe the commit message could be
improved. The reference [1] is not the best to make things clear, maybe
[2] could be better undstood. It is even better if there is a brief
introduction of the DMA API change in the commit message. It saves a lot
of time for reviewers.
I see there are plenty of similar places to change, could you make a
patchset and change them in a batch?
[2]: https://lists.linuxfoundation.org/pipermail/iommu/2019-February/033674.html
Thanks,
Yilun
>
> Simplify code and remove some dead code accordingly.
>
> [1]: https://lkml.org/lkml/2021/6/7/398
>
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
> ---
> drivers/fpga/dfl-pci.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index 717ac9715970..42fdfa7a28d6 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -356,8 +356,6 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
> pci_set_master(pcidev);
>
> ret = dma_set_mask_and_coherent(&pcidev->dev, DMA_BIT_MASK(64));
> - if (ret)
> - ret = dma_set_mask_and_coherent(&pcidev->dev, DMA_BIT_MASK(32));
> if (ret) {
> dev_err(&pcidev->dev, "No suitable DMA support available.\n");
> goto disable_error_report_exit;
> --
> 2.25.1
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-03-18 10:34 ` Xu Yilun
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