drm/amdgpu: fix VM page table reference counting

We use the reservation object of the page directory for the page tables as
well, because of this the page directory should be freed last. Ensure that
by keeping a reference from the page tables to the directory.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 251b14736de92b7ff429d01f9d257c3b918b6547..670fefb56945258faf899b708047a2bd83685a59 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -539,6 +539,7 @@ struct amdgpu_bo {
        /* Constant after initialization */
        struct amdgpu_device            *adev;
        struct drm_gem_object           gem_base;
+       struct amdgpu_bo                *parent;
 
        struct ttm_bo_kmap_obj          dma_buf_vmap;
        pid_t                           pid;

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 0d524384ff79c3b49d2dbaa1489d8cbff231d80a..c3ce103b6a33b2ef3a0a6f7f14877e18150ca405 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -100,6 +100,7 @@ static void amdgpu_ttm_bo_destroy(struct ttm_buffer_object *tbo)
        list_del_init(&bo->list);
        mutex_unlock(&bo->adev->gem.mutex);
        drm_gem_object_release(&bo->gem_base);
+       amdgpu_bo_unref(&bo->parent);
        kfree(bo->metadata);
        kfree(bo);
 }

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index ae037e5b6ad016d6ee70545b814d082da84f22c3..a582ef5534992f7d2e1e3b69bc6a666591958016 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1079,6 +1079,11 @@ int amdgpu_vm_bo_map(struct amdgpu_device *adev,
                if (r)
                        goto error_free;
 
+               /* Keep a reference to the page table to avoid freeing
+                * them up in the wrong order.
+                */
+               pt->parent = amdgpu_bo_ref(vm->page_directory);
+
                r = amdgpu_vm_clear_bo(adev, pt);
                if (r) {
                        amdgpu_bo_unref(&pt);