gpu: nvgpu: Clear PTE ref after freeing

When clearing sparse buffers, pte->ref must be cleared once the PTE
is freed.

Bug 1549451

Change-Id: Ie7d3e438ef2c43cbcf893709ae50a67823bf0c9c
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/494670
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Shridhar Rasal <srasal@nvidia.com>
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/mm_gm20b.c b/drivers/gpu/nvgpu/gm20b/mm_gm20b.c
index fd0d058f..0f9749f7 100644
--- a/drivers/gpu/nvgpu/gm20b/mm_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/mm_gm20b.c
@@ -308,6 +308,7 @@ void gm20b_vm_clear_sparse(struct vm_gk20a *vm, u64 vaddr,
                         free_gmmu_pages(vm, pte->ref, pte->sgt,
                                 vm->mm->page_table_sizing[pgsz_idx].order,
                                 pte->size);
+                        pte->ref = NULL;
                         update_gmmu_pde_locked(vm, pde_i);
                 }
         }