[PATCH] drm/ttm: Fix 'buf' pointer update in ttm_bo_vm_access_kmap() (v2)

[Felix Kuehling]

On 2018-01-29 09:34 AM, Tom St Denis wrote:
> The buf pointer was not being incremented inside the loop
> meaning the same block of data would be read or written
> repeatedly.
>
> Fixes: 09ac4fcb3f25 ("drm/ttm: Implement vm_operations_struct.access v2")
>
> Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
> Reviewed-by: Christian König <christian.koenig at amd.com>

Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>

>
> (v2) Change 'buf' pointer to uint8_t* type
> ---
>  drivers/gpu/drm/ttm/ttm_bo_vm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index 08a3c324242e..60fcef1593dd 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -316,7 +316,7 @@ static void ttm_bo_vm_close(struct vm_area_struct *vma)
>  
>  static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
>  				 unsigned long offset,
> -				 void *buf, int len, int write)
> +				 uint8_t *buf, int len, int write)
>  {
>  	unsigned long page = offset >> PAGE_SHIFT;
>  	unsigned long bytes_left = len;
> @@ -345,6 +345,7 @@ static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
>  		ttm_bo_kunmap(&map);
>  
>  		page++;
> +		buf += bytes;
>  		bytes_left -= bytes;
>  		offset = 0;
>  	} while (bytes_left);