Commit e3eb0e70 authored by Chen-Yu Tsai's avatar Chen-Yu Tsai
Browse files

drm/gem-dma: set VM_DONTDUMP for mmap 



When the mmap function was converted from a file op to a GEM object
function in commit f5ca8eb6 ("drm/cma-helper: Implement mmap as GEM
CMA object functions") some VM flags were not lifted from drm_gem_mmap():

  - VM_IO
  - VM_DONTEXPAND
  - VM_DONTDUMP

VM_DONTEXPAND was added back in commit 59f39bfa ("drm/cma-helper:
Set VM_DONTEXPAND for mmap"). VM_IO doesn't make sense since these are
memory buffers, while "IO tells people not to look at these pages
(accesses can have side effects)".

Add back VM_DONTDUMP. This matches the behavior of most other GEM
implementations.

Reviewed-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/20260317040034.617585-1-wenst@chromium.org


Signed-off-by: default avatarChen-Yu Tsai <wenst@chromium.org>
parent 1f513a3e

drivers/gpu/drm/drm_gem_dma_helper.c

+1 −1
Original line number Diff line number Diff line
@@ -537,7 +537,7 @@ int drm_gem_dma_mmap(struct drm_gem_dma_object *dma_obj, struct vm_area_struct * 
	 * the whole buffer.

	 */

	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);

	vm_flags_mod(vma, VM_DONTEXPAND, VM_PFNMAP);

	vm_flags_mod(vma, VM_DONTDUMP | VM_DONTEXPAND, VM_PFNMAP);



	if (dma_obj->map_noncoherent) {

		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);