[PATCH] drm/amdgpu: GPU vs CPU page size fixes in amdgpu_vm_bo_split_mapping

[Christian König]

Am 22.06.2018 um 11:10 schrieb Michel Dänzer:
> From: Michel Dänzer <michel.daenzer at amd.com>
>
> start / last / max_entries are numbers of GPU pages, pfn / count are
> numbers of CPU pages. Convert between them accordingly.
>
> Fixes badness on systems with > 4K page size.
>
> Cc: stable at vger.kernel.org
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106258
> Reported-by: Matt Corallo <freedesktop at bluematt.me>
> Tested-by: foxbat at ruin.net
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

Nice work! Just one comment: Can we somewhere add a define for 
"(PAGE_SIZE / AMDGPU_GPU_PAGE_SIZE)"?

IIRC that term was used in the GART code as well and just adding it 
somewhere could makes things cleaner if you ask me.

Christian.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 7c30451ba897..590db78b8c72 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1577,7 +1577,9 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
>   			uint64_t count;
>   
>   			max_entries = min(max_entries, 16ull * 1024ull);
> -			for (count = 1; count < max_entries; ++count) {
> +			for (count = 1;
> +			     count < max_entries / (PAGE_SIZE / AMDGPU_GPU_PAGE_SIZE);
> +			     ++count) {
>   				uint64_t idx = pfn + count;
>   
>   				if (pages_addr[idx] !=
> @@ -1590,7 +1592,7 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
>   				dma_addr = pages_addr;
>   			} else {
>   				addr = pages_addr[pfn];
> -				max_entries = count;
> +				max_entries = count * (PAGE_SIZE / AMDGPU_GPU_PAGE_SIZE);
>   			}
>   
>   		} else if (flags & AMDGPU_PTE_VALID) {
> @@ -1605,7 +1607,7 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
>   		if (r)
>   			return r;
>   
> -		pfn += last - start + 1;
> +		pfn += (last - start + 1) / (PAGE_SIZE / AMDGPU_GPU_PAGE_SIZE);
>   		if (nodes && nodes->size == pfn) {
>   			pfn = 0;
>   			++nodes;