drm/amdgpu: change vm->task_info handling

This patch changes the handling and lifecycle of vm->task_info object.
The major changes are:
- vm->task_info is a dynamically allocated ptr now, and its uasge is
  reference counted.
- introducing two new helper funcs for task_info lifecycle management
    - amdgpu_vm_get_task_info: reference counts up task_info before
      returning this info
    - amdgpu_vm_put_task_info: reference counts down task_info
- last put to task_info() frees task_info from the vm.

This patch also does logistical changes required for existing usage
of vm->task_info.

V2: Do not block all the prints when task_info not found (Felix)

V3: Fixed review comments from Felix
   - Fix wrong indentation
   - No debug message for -ENOMEM
   - Add NULL check for task_info
   - Do not duplicate the debug messages (ti vs no ti)
   - Get first reference of task_info in vm_init(), put last
     in vm_fini()

V4: Fixed review comments from Felix
   - fix double reference increment in create_task_info
   - change amdgpu_vm_get_task_info_pasid
   - additional changes in amdgpu_gem.c while porting

Cc: Christian Koenig <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Felix Kuehling <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Signed-off-by: Shashank Sharma <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 22aeee8adb71..67c234bcf89f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -208,9 +208,15 @@ static int amdgpu_gem_object_open(struct drm_gem_object *obj,
 	if (!WARN_ON(!vm->process_info->eviction_fence)) {
 		r = amdgpu_amdkfd_bo_validate_and_fence(abo, AMDGPU_GEM_DOMAIN_GTT,
 							&vm->process_info->eviction_fence->base);
-		if (r)
-			dev_warn(adev->dev, "%d: validate_and_fence failed: %d\n",
-				 vm->task_info.pid, r);
+		if (r) {
+			struct amdgpu_task_info *ti = amdgpu_vm_get_task_info_vm(vm);
+
+			dev_warn(adev->dev, "validate_and_fence failed: %d\n", r);
+			if (ti) {
+				dev_warn(adev->dev, "pid %d\n", ti->pid);
+				amdgpu_vm_put_task_info(ti);
+			}
+		}
 	}
 	mutex_unlock(&vm->process_info->lock);