When the mmap function was converted from a file op to a GEM object
function in commit f5ca8eb6f9bd ("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 59f39bfa6553 ("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.
Signed-off-by: Chen-Yu Tsai <[email protected]>
---
Cc: Thomas Zimmermann <[email protected]>
---
drivers/gpu/drm/drm_gem_dma_helper.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c
b/drivers/gpu/drm/drm_gem_dma_helper.c
index ecb9746f4da8..1911bf6a6a3e 100644
--- a/drivers/gpu/drm/drm_gem_dma_helper.c
+++ b/drivers/gpu/drm/drm_gem_dma_helper.c
@@ -534,7 +534,7 @@ 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);
--
2.53.0.851.ga537e3e6e9-goog
