On Thu, 28 Nov 2024 21:06:20 +0000
Adrián Larumbe <adrian.laru...@collabora.com> wrote:

> When mapping the pages of a BO, either a heap type at page fault time or
> else a non-heap BO at object creation time, if the ARM page table mapping
> function fails, we unmap what had been mapped so far and bail out.
> 
> Signed-off-by: Adrián Larumbe <adrian.laru...@collabora.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_mmu.c | 44 ++++++++++++++++++++++---
>  1 file changed, 39 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
> b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index 03ac527b35e7..5e30888bea0e 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -290,13 +290,31 @@ static void panfrost_mmu_flush_range(struct 
> panfrost_device *pfdev,
>       pm_runtime_put_autosuspend(pfdev->base.dev);
>  }
>  
> +static void mmu_unmap_range(size_t len, u64 iova, struct io_pgtable_ops *ops)

Can we use the following prototype instead?

static void mmu_unmap_range(struct panfrost_mmu *mmu,
                            u64 iova, size_t len)

> +{
> +     size_t pgsize, unmapped_len = 0;
> +     size_t unmapped_page, pgcount;
> +
> +     while (unmapped_len < len) {
> +             pgsize = get_pgsize(iova, len - unmapped_len, &pgcount);
> +
> +             unmapped_page = ops->unmap_pages(ops, iova, pgsize, pgcount, 
> NULL);
> +             WARN_ON(unmapped_page != pgsize * pgcount);
> +
> +             iova += pgsize * pgcount;
> +             unmapped_len += pgsize * pgcount;
> +     }
> +}
> +
>  static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu,
>                     u64 iova, int prot, struct sg_table *sgt)
>  {
>       unsigned int count;
>       struct scatterlist *sgl;
>       struct io_pgtable_ops *ops = mmu->pgtbl_ops;
> +     size_t total_mapped = 0;
>       u64 start_iova = iova;
> +     int ret = 0;
>  
>       for_each_sgtable_dma_sg(sgt, sgl, count) {
>               unsigned long paddr = sg_dma_address(sgl);
> @@ -310,10 +328,15 @@ static int mmu_map_sg(struct panfrost_device *pfdev, 
> struct panfrost_mmu *mmu,
>                       size_t pgcount, mapped = 0;
>                       size_t pgsize = get_pgsize(iova | paddr, len, &pgcount);
>  
> -                     ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot,
> +                     ret = ops->map_pages(ops, iova, paddr, pgsize, pgcount, 
> prot,
>                                      GFP_KERNEL, &mapped);
> +                     if (ret) {
> +                             mmu_unmap_range(total_mapped, start_iova, ops);
> +                             return ret;

I general, I'm not a huge fan of those error paths where things are
undone manually, because they tend to be overlooked when new steps are
added. I'd rather have a  "goto error_unmap_pages;" here, and the
according label defined at the end of the function.

> +                     }
>                       /* Don't get stuck if things have gone wrong */
>                       mapped = max(mapped, pgsize);
> +                     total_mapped += mapped;
>                       iova += mapped;
>                       paddr += mapped;
>                       len -= mapped;
> @@ -333,6 +356,7 @@ int panfrost_mmu_map(struct panfrost_gem_mapping *mapping)
>       struct panfrost_device *pfdev = to_panfrost_device(obj->dev);
>       struct sg_table *sgt;
>       int prot = IOMMU_READ | IOMMU_WRITE;
> +     int ret;
>  
>       if (WARN_ON(mapping->active))
>               return 0;
> @@ -344,8 +368,13 @@ int panfrost_mmu_map(struct panfrost_gem_mapping 
> *mapping)
>       if (WARN_ON(IS_ERR(sgt)))
>               return PTR_ERR(sgt);
>  
> -     mmu_map_sg(pfdev, mapping->mmu, mapping->mmnode.start << PAGE_SHIFT,
> -                prot, sgt);
> +     ret = mmu_map_sg(pfdev, mapping->mmu, mapping->mmnode.start << 
> PAGE_SHIFT,
> +                      prot, sgt);
> +     if (ret) {
> +             drm_gem_shmem_put_pages(shmem);

Same here.

> +             return ret;
> +     }
> +
>       mapping->active = true;
>  
>       return 0;
> @@ -532,8 +561,10 @@ static int panfrost_mmu_map_fault_addr(struct 
> panfrost_device *pfdev, int as,
>       if (ret)
>               goto err_map;
>  
> -     mmu_map_sg(pfdev, bomapping->mmu, addr,
> -                IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
> +     ret = mmu_map_sg(pfdev, bomapping->mmu, addr,
> +                      IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
> +     if (ret)
> +             goto err_mmu_map_sg;
>  
>       bomapping->active = true;
>       bo->heap_rss_size += SZ_2M;
> @@ -547,6 +578,9 @@ static int panfrost_mmu_map_fault_addr(struct 
> panfrost_device *pfdev, int as,
>  
>       return 0;
>  
> +err_mmu_map_sg:
> +     dma_unmap_sgtable(pfdev->base.dev, sgt,
> +                       DMA_BIDIRECTIONAL, 0);
>  err_map:
>       sg_free_table(sgt);
>  err_unlock:

Reply via email to