Re: [PATCH] iommu/ipmmu-vmsa: Check for error num after setting mask
On Mon, Feb 14, 2022 at 12:32:21PM +, Robin Murphy wrote: > In this particular case it cannot fail on any system the driver actually > runs on - it's a platform device so the dma_mask pointer is always > initialised, then dma_direct_supported() on arm64 will always return true > for any mask wider than 32 bits, while arm_dma_supported() will also always > pass since a 32-bit system cannot have memory above 40 bits either. > > There's no great harm in adding the check for the sake of consistency, I > guess, but it's purely cosmetic and not fixing anything. Okay, thanks Robin and Nikita for looking to quickly into this. I will apply it for 5.18 just to be on the safe side if the above assumptions change. Regards, Joerg ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH] iommu/ipmmu-vmsa: Check for error num after setting mask
On 2022-02-14 11:43, Joerg Roedel wrote:
Adding more potential reviewers.
On Thu, Jan 06, 2022 at 10:43:02AM +0800, Jiasheng Jiang wrote:
Because of the possible failure of the dma_supported(), the
dma_set_mask_and_coherent() may return error num.
Therefore, it should be better to check it and return the error if
fails.
In this particular case it cannot fail on any system the driver actually
runs on - it's a platform device so the dma_mask pointer is always
initialised, then dma_direct_supported() on arm64 will always return
true for any mask wider than 32 bits, while arm_dma_supported() will
also always pass since a 32-bit system cannot have memory above 40 bits
either.
There's no great harm in adding the check for the sake of consistency, I
guess, but it's purely cosmetic and not fixing anything.
Thanks,
Robin.
Fixes: 1c894225bf5b ("iommu/ipmmu-vmsa: IPMMU device is 40-bit bus master")
Signed-off-by: Jiasheng Jiang
---
drivers/iommu/ipmmu-vmsa.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index aaa6a4d59057..7df5da44a004 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -1003,7 +1003,9 @@ static int ipmmu_probe(struct platform_device *pdev)
bitmap_zero(mmu->ctx, IPMMU_CTX_MAX);
mmu->features = of_device_get_match_data(&pdev->dev);
memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
- dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
+ if (ret)
+ return ret;
/* Map I/O memory and request IRQ. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
--
2.25.1
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Re: [PATCH] iommu/ipmmu-vmsa: Check for error num after setting mask
Adding more potential reviewers. On Thu, Jan 06, 2022 at 10:43:02AM +0800, Jiasheng Jiang wrote: Because of the possible failure of the dma_supported(), the dma_set_mask_and_coherent() may return error num. Therefore, it should be better to check it and return the error if fails. Indeed, most uses of dma_set_mask_and_coherent() in the kernel do check return value. Reviewed-by: Nikita Yushchenko ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH] iommu/ipmmu-vmsa: Check for error num after setting mask
Adding more potential reviewers.
On Thu, Jan 06, 2022 at 10:43:02AM +0800, Jiasheng Jiang wrote:
> Because of the possible failure of the dma_supported(), the
> dma_set_mask_and_coherent() may return error num.
> Therefore, it should be better to check it and return the error if
> fails.
>
> Fixes: 1c894225bf5b ("iommu/ipmmu-vmsa: IPMMU device is 40-bit bus master")
> Signed-off-by: Jiasheng Jiang
> ---
> drivers/iommu/ipmmu-vmsa.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
> index aaa6a4d59057..7df5da44a004 100644
> --- a/drivers/iommu/ipmmu-vmsa.c
> +++ b/drivers/iommu/ipmmu-vmsa.c
> @@ -1003,7 +1003,9 @@ static int ipmmu_probe(struct platform_device *pdev)
> bitmap_zero(mmu->ctx, IPMMU_CTX_MAX);
> mmu->features = of_device_get_match_data(&pdev->dev);
> memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
> - dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
> + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
> + if (ret)
> + return ret;
>
> /* Map I/O memory and request IRQ. */
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> --
> 2.25.1
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[PATCH] iommu/ipmmu-vmsa: Check for error num after setting mask
Because of the possible failure of the dma_supported(), the
dma_set_mask_and_coherent() may return error num.
Therefore, it should be better to check it and return the error if
fails.
Fixes: 1c894225bf5b ("iommu/ipmmu-vmsa: IPMMU device is 40-bit bus master")
Signed-off-by: Jiasheng Jiang
---
drivers/iommu/ipmmu-vmsa.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index aaa6a4d59057..7df5da44a004 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -1003,7 +1003,9 @@ static int ipmmu_probe(struct platform_device *pdev)
bitmap_zero(mmu->ctx, IPMMU_CTX_MAX);
mmu->features = of_device_get_match_data(&pdev->dev);
memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
- dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
+ if (ret)
+ return ret;
/* Map I/O memory and request IRQ. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
--
2.25.1
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