Re: [Intel-gfx] [PATCH 2/2] drm/i915/dmabuf: Fix prime_mmap to work when using LMEM

["Das, Nirmoy" <nirmoy.das@linux.intel.com>]

LGTM Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>

On 25/02/2022 14:13, Gwan-gyeong Mun wrote:
> The current implementation of i915 prime mmap only works when initializing
> drm_i915_gem_object with shmem_region.
> When using LMEM, drm_i915_gem_object is initialized with ttm_system_region.
> In order to make prime mmap work even this case, when using LMEM
> (when using ttm in i915), dma_buf_ops.mmap callback function calls
> drm_gem_prime_mmap(). drm_gem_prime_mmap() of drm core calls internally
> i915_gem_mmap() so that prime mmap can perform normally.
> The fake offset is processed inside drm_gem_prime_mmap().
>
> Testcase: igt/prime_mmap
>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> index af899ae1f3c7..f5062d0c6333 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> @@ -93,11 +93,15 @@ static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf,
>   static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
>   {
>   	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
> +	struct drm_i915_private *i915 = to_i915(obj->base.dev);
>   	int ret;
>   
>   	if (obj->base.size < vma->vm_end - vma->vm_start)
>   		return -EINVAL;
>   
> +	if (HAS_LMEM(i915))
> +		return drm_gem_prime_mmap(&obj->base, vma);
> +
>   	if (!obj->base.filp)
>   		return -ENODEV;
>