drm/ttm: remove ttm_bo_(un)lock_delayed_workqueue

Those functions never worked correctly since it is still perfectly
possible that a buffer object is released and the background worker
restarted even after calling them.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221125102137.1801-2-christian.koenig@amd.com

drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c

@@ -1717,7 +1717,7 @@ no_preempt:
 
 static int amdgpu_debugfs_ib_preempt(void *data, u64 val)
 {
-	int r, resched, length;
+	int r, length;
 	struct amdgpu_ring *ring;
 	struct dma_fence **fences = NULL;
 	struct amdgpu_device *adev = (struct amdgpu_device *)data;
@@ -1747,8 +1747,6 @@ static int amdgpu_debugfs_ib_preempt(void *data, u64 val)
 	/* stop the scheduler */
 	kthread_park(ring->sched.thread);
 
-	resched = ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
-
 	/* preempt the IB */
 	r = amdgpu_ring_preempt_ib(ring);
 	if (r) {
@@ -1785,8 +1783,6 @@ failure:
 
 	up_read(&adev->reset_domain->sem);
 
-	ttm_bo_unlock_delayed_workqueue(&adev->mman.bdev, resched);
-
 pro_end:
 	kfree(fences);
 

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -3983,10 +3983,8 @@ void amdgpu_device_fini_hw(struct amdgpu_device *adev)
 	}
 	amdgpu_fence_driver_hw_fini(adev);
 
-	if (adev->mman.initialized) {
+	if (adev->mman.initialized)
 		flush_delayed_work(&adev->mman.bdev.wq);
-		ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
-	}
 
 	if (adev->pm_sysfs_en)
 		amdgpu_pm_sysfs_fini(adev);

drivers/gpu/drm/radeon/radeon_device.c

@@ -1772,7 +1772,6 @@ int radeon_gpu_reset(struct radeon_device *rdev)
 	bool saved = false;
 
 	int i, r;
-	int resched;
 
 	down_write(&rdev->exclusive_lock);
 
@@ -1784,8 +1783,6 @@ int radeon_gpu_reset(struct radeon_device *rdev)
 	atomic_inc(&rdev->gpu_reset_counter);
 
 	radeon_save_bios_scratch_regs(rdev);
-	/* block TTM */
-	resched = ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
 	radeon_suspend(rdev);
 	radeon_hpd_fini(rdev);
 
@@ -1844,8 +1841,6 @@ int radeon_gpu_reset(struct radeon_device *rdev)
 	/* reset hpd state */
 	radeon_hpd_init(rdev);
 
-	ttm_bo_unlock_delayed_workqueue(&rdev->mman.bdev, resched);
-
 	rdev->in_reset = true;
 	rdev->needs_reset = false;
 

drivers/gpu/drm/radeon/radeon_pm.c

@@ -1853,11 +1853,10 @@ static bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish
 static void radeon_dynpm_idle_work_handler(struct work_struct *work)
 {
 	struct radeon_device *rdev;
-	int resched;
+
 	rdev = container_of(work, struct radeon_device,
 				pm.dynpm_idle_work.work);
 
-	resched = ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
 	mutex_lock(&rdev->pm.mutex);
 	if (rdev->pm.dynpm_state == DYNPM_STATE_ACTIVE) {
 		int not_processed = 0;
@@ -1908,7 +1907,6 @@ static void radeon_dynpm_idle_work_handler(struct work_struct *work)
 				      msecs_to_jiffies(RADEON_IDLE_LOOP_MS));
 	}
 	mutex_unlock(&rdev->pm.mutex);
-	ttm_bo_unlock_delayed_workqueue(&rdev->mman.bdev, resched);
 }
 
 /*

drivers/gpu/drm/ttm/ttm_bo.c

@@ -418,20 +418,6 @@ void ttm_bo_put(struct ttm_buffer_object *bo)
 }
 EXPORT_SYMBOL(ttm_bo_put);
 
-int ttm_bo_lock_delayed_workqueue(struct ttm_device *bdev)
-{
-	return cancel_delayed_work_sync(&bdev->wq);
-}
-EXPORT_SYMBOL(ttm_bo_lock_delayed_workqueue);
-
-void ttm_bo_unlock_delayed_workqueue(struct ttm_device *bdev, int resched)
-{
-	if (resched)
-		schedule_delayed_work(&bdev->wq,
-				      ((HZ / 100) < 1) ? 1 : HZ / 100);
-}
-EXPORT_SYMBOL(ttm_bo_unlock_delayed_workqueue);
-
 static int ttm_bo_bounce_temp_buffer(struct ttm_buffer_object *bo,
 				     struct ttm_resource **mem,
 				     struct ttm_operation_ctx *ctx,

include/drm/ttm/ttm_bo_api.h

@@ -290,22 +290,6 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo);
 void ttm_bo_set_bulk_move(struct ttm_buffer_object *bo,
 			  struct ttm_lru_bulk_move *bulk);
 
-/**
- * ttm_bo_lock_delayed_workqueue
- *
- * Prevent the delayed workqueue from running.
- * Returns
- * True if the workqueue was queued at the time
- */
-int ttm_bo_lock_delayed_workqueue(struct ttm_device *bdev);
-
-/**
- * ttm_bo_unlock_delayed_workqueue
- *
- * Allows the delayed workqueue to run.
- */
-void ttm_bo_unlock_delayed_workqueue(struct ttm_device *bdev, int resched);
-
 /**
  * ttm_bo_eviction_valuable
  *