Re: [PATCH v2 1/6] iommu: Move iotlb_sync_map out from __iommu_map

Robin Murphy
2020-11-25T16:38:10Z

On 2020-11-19 06:18, Yong Wu wrote:
> In the end of __iommu_map, It alway call iotlb_sync_map.
> This patch moves iotlb_sync_map out from __iommu_map since it is
> unnecessary to call this for each sg segment especially iotlb_sync_map
> is flush tlb all currently.

I don't see a way to avoid the boilerplate that wouldn't end up making
things even more ugly and complicated, so:

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/iommu/iommu.c | 24 +++++++++++++++++++-----
> 1 file changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 8c470f451a32..decef851fa3a 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2407,9 +2407,6 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
> size -= pgsize;
> }
>
> - if (ops->iotlb_sync_map)
> - ops->iotlb_sync_map(domain);
> -
> /* unroll mapping in case something went wrong */
> if (ret)
> iommu_unmap(domain, orig_iova, orig_size - size);
> @@ -2422,15 +2419,29 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
> int iommu_map(struct iommu_domain *domain, unsigned long iova,
> phys_addr_t paddr, size_t size, int prot)
> {
> + const struct iommu_ops *ops = domain->ops;
> + int ret;
> +
> might_sleep();
> - return __iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL);
> + ret = __iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL);
> + if (ret == 0 && ops->iotlb_sync_map)
> + ops->iotlb_sync_map(domain);
> +
> + return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_map);
>
> int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
> phys_addr_t paddr, size_t size, int prot)
> {
> - return __iommu_map(domain, iova, paddr, size, prot, GFP_ATOMIC);
> + const struct iommu_ops *ops = domain->ops;
> + int ret;
> +
> + ret = __iommu_map(domain, iova, paddr, size, prot, GFP_ATOMIC);
> + if (ret == 0 && ops->iotlb_sync_map)
> + ops->iotlb_sync_map(domain);
> +
> + return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_map_atomic);
>
> @@ -2514,6 +2525,7 @@ static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
> struct scatterlist *sg, unsigned int nents, int prot,
> gfp_t gfp)
> {
> + const struct iommu_ops *ops = domain->ops;
> size_t len = 0, mapped = 0;
> phys_addr_t start;
> unsigned int i = 0;
> @@ -2544,6 +2556,8 @@ static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
> sg = sg_next(sg);
> }
>
> + if (ops->iotlb_sync_map)
> + ops->iotlb_sync_map(domain);
> return mapped;
>
> out_err:
>