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From:   Yusuf Khan <yusisamerican@gmail.com>
Date:   Mon, 21 Feb 2022 20:39:48 -0800
Message-ID: <CAJoG2+-97KyWrxym2NXECRtjT9OxVQE_=DcNkUfOsPm_Ax90Aw@mail.gmail.com>
Subject: Re: [PATCH -next] pga: dfl: pci: Make sure DMA related error check is
 not done twice
To:     linux-kernel@vger.kernel.org
Cc:     linux-fpga@vger.kernel.org, yilun.xu@intel.com, mdf@kernel.org,
        trix@redhat.com, hao.wu@intel.com
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Note: This bug was introduced here:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/patch/?id=ada3caabaf6135150077c3f729bb06e8f3b5b8f6
I saw this commit inside the linux-next branch, it is not present in
the mainline branch.
The linux-next branch was last updated 5 days ago, so I am unsure
about the state of that commit.

On Mon, Feb 21, 2022 at 8:27 PM Yusuf Khan <yusisamerican@gmail.com> wrote:
>
> In the case that the DMA 64 bit bit mask error check does not fail,
> the error check will be done twice, this patch fixed that.
>
> NOTE: This patch is only for use in the linux-next branch as the
> commit that caused this bug happened there.
>
> Signed-off-by: Yusuf Khan <yusisamerican@gmail.com>
> ---
>  drivers/fpga/dfl-pci.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index 717ac9715970..6222f18aed4b 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -356,11 +356,12 @@ 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;
> +               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;
> +               }
>         }
>
>         ret = cci_init_drvdata(pcidev);
> --
> 2.25.1
>