Hi Krzysztof,
On Wed, 2026-05-27 at 14:08 +0000, Krzysztof Karas wrote:
> Currently, if iommu maps fewer bytes than requested (iova_len),
> it proceeds to free the iova, but never tries to unmap already
> touched bytes. This behavior may cause memory hogging down the
> line.
>
> Correct that by unmapping before exiting.
>
> Signed-off-by: Krzysztof Karas <[email protected]>
> ---
> drivers/iommu/dma-iommu.c | 10 ++++++++--
You have to submit this patch to IOMMU DMA-API LAYER maintainers (see
MAINTAINERS file for list and maintainer addresses) in order to get binding
comments, I believe.
Thanks,
Janusz
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 54d96e847f16..64ac2bdfc574 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1515,8 +1515,14 @@ int iommu_dma_map_sg(struct device *dev, struct
> scatterlist *sg, int nents,
> * implementation - it knows better than we do.
> */
> ret = iommu_map_sg(domain, iova, sg, nents, prot, GFP_ATOMIC);
> - if (ret < 0 || ret < iova_len)
> + if (ret < 0 || ret < iova_len) {
> + if (ret > 0) {
> + /* Unmap partially mapped bytes before freeing IOVA */
> + if (iommu_unmap(domain, iova, ret) != ret)
> + ret = -EIO;
> + }
> goto out_free_iova;
> + }
>
> return __finalise_sg(dev, sg, nents, iova);
>
> @@ -1525,7 +1531,7 @@ int iommu_dma_map_sg(struct device *dev, struct
> scatterlist *sg, int nents,
> out_restore_sg:
> __invalidate_sg(sg, nents);
> out:
> - if (ret != -ENOMEM && ret != -EREMOTEIO)
> + if (ret != -ENOMEM && ret != -EREMOTEIO && ret != -EIO)
> return -EINVAL;
> return ret;
> }
