On Thu, Mar 20, 2025 at 05:29:59PM +0000, Matthew Auld wrote:
> If we are only reading the memory then from the device pov the direction
> can be DMA_TO_DEVICE. This aligns with the xe-userptr code. Using the
> most restrictive data direction to represent the access is normally a
> good idea.
>
> Signed-off-by: Matthew Auld <matthew.a...@intel.com>
> Cc: Thomas Hellström <thomas.hellst...@linux.intel.com>
> Cc: Matthew Brost <matthew.br...@intel.com>
Reviewed-by: Matthew Brost <matthew.br...@intel.com>
> ---
> drivers/gpu/drm/drm_gpusvm.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
> index 48993cef4a74..7f1cf5492bba 100644
> --- a/drivers/gpu/drm/drm_gpusvm.c
> +++ b/drivers/gpu/drm/drm_gpusvm.c
> @@ -1355,6 +1355,8 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm
> *gpusvm,
> int err = 0;
> struct dev_pagemap *pagemap;
> struct drm_pagemap *dpagemap;
> + enum dma_data_direction dma_dir = ctx->read_only ? DMA_TO_DEVICE :
> + DMA_BIDIRECTIONAL;
>
> retry:
> hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
> @@ -1459,7 +1461,7 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm
> *gpusvm,
> dpagemap->ops->device_map(dpagemap,
> gpusvm->drm->dev,
> page, order,
> - DMA_BIDIRECTIONAL);
> + dma_dir);
> if (dma_mapping_error(gpusvm->drm->dev,
> range->dma_addr[j].addr)) {
> err = -EFAULT;
> @@ -1478,7 +1480,7 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm
> *gpusvm,
> addr = dma_map_page(gpusvm->drm->dev,
> page, 0,
> PAGE_SIZE << order,
> - DMA_BIDIRECTIONAL);
> + dma_dir);
> if (dma_mapping_error(gpusvm->drm->dev, addr)) {
> err = -EFAULT;
> goto err_unmap;
> @@ -1486,7 +1488,7 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm
> *gpusvm,
>
> range->dma_addr[j] = drm_pagemap_device_addr_encode
> (addr, DRM_INTERCONNECT_SYSTEM, order,
> - DMA_BIDIRECTIONAL);
> + dma_dir);
> }
> i += 1 << order;
> num_dma_mapped = i;
> --
> 2.48.1
>
