[PATCH v5 5/7] drm/amdgpu: get rid of amdgpu_ttm_clear_buffer - Linaro-mm-sig

3 Apr 2026

It's doing the same thing as amdgpu_fill_buffer(src_data=0), so drop it.
The only caveat is that amdgpu_res_cleared() return value is only valid
right after allocation.
---
v2: introduce new "bool consider_clear_status" arg
---
Signed-off-by: Pierre-Eric Pelloux-Prayer pierre-eric.pelloux-prayer@amd.com
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 16 ++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 88 +++++-----------------
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h    |  6 +-
 3 files changed, 32 insertions(+), 78 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 66c20dd46d12..d0884bbffa75 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -717,13 +717,17 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
        bo->tbo.resource->mem_type == TTM_PL_VRAM) {
    	struct dma_fence *fence;
-		r = amdgpu_ttm_clear_buffer(bo, bo->tbo.base.resv, &fence);
+		r = amdgpu_fill_buffer(amdgpu_ttm_next_clear_entity(adev),
+				       bo, 0, NULL, &fence,
+				       true, AMDGPU_KERNEL_JOB_ID_TTM_CLEAR_BUFFER);
    	if (unlikely(r))
    		goto fail_unreserve;
-		dma_resv_add_fence(bo->tbo.base.resv, fence,
-				   DMA_RESV_USAGE_KERNEL);
-		dma_fence_put(fence);
+		if (fence) {
+			dma_resv_add_fence(bo->tbo.base.resv, fence,
+					   DMA_RESV_USAGE_KERNEL);
+			dma_fence_put(fence);
+		}
    }
    if (!bp->resv)
    	amdgpu_bo_unreserve(bo);
@@ -1326,8 +1330,8 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
    	goto out;
r = amdgpu_fill_buffer(amdgpu_ttm_next_clear_entity(adev),
-			       abo, 0, &bo->base._resv,
-			       &fence, AMDGPU_KERNEL_JOB_ID_CLEAR_ON_RELEASE);
+			       abo, 0, &bo->base._resv, &fence,
+			       false, AMDGPU_KERNEL_JOB_ID_CLEAR_ON_RELEASE);
    if (WARN_ON(r))
    	goto out;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 648ad344e89c..a3d0998b8cec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -418,7 +418,7 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
        (abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
    	struct dma_fence *wipe_fence = NULL;
    	r = amdgpu_fill_buffer(entity, abo, 0, NULL, &wipe_fence,
-				       AMDGPU_KERNEL_JOB_ID_MOVE_BLIT);
+				       false, AMDGPU_KERNEL_JOB_ID_MOVE_BLIT);
    	if (r) {
    		goto error;
    	} else if (wipe_fence) {
@@ -2572,76 +2572,25 @@ static int amdgpu_ttm_fill_mem(struct amdgpu_device *adev,
 }
/**
- * amdgpu_ttm_clear_buffer - clear memory buffers
- * @bo: amdgpu buffer object
- * @resv: reservation object
- * @fence: dma_fence associated with the operation
+ * amdgpu_fill_buffer - fill a buffer with a given value
+ * @entity: entity to use
+ * @bo: the bo to fill
+ * @src_data: the value to set
+ * @resv: fences contained in this reservation will be used as dependencies.
+ * @out_fence: the fence from the last clear will be stored here. It might be
+ *             NULL if no job was run.
+ * @dependency: optional input dependency fence.
+ * @consider_clear_status: true if region reported as cleared by amdgpu_res_cleared()
+ *                         are skipped.
+ * @k_job_id: trace id
  *
- * Clear the memory buffer resource.
- *
- * Returns:
- * 0 for success or a negative error code on failure.
  */
-int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
-			    struct dma_resv *resv,
-			    struct dma_fence **fence)
-{
-	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
-	struct amdgpu_ttm_buffer_entity *entity;
-	struct amdgpu_res_cursor cursor;
-	u64 addr;
-	int r = 0;
-
-	if (!adev->mman.buffer_funcs_enabled)
-		return -EINVAL;
-
-	if (!fence)
-		return -EINVAL;
-	entity = &adev->mman.clear_entities[0];
-	*fence = dma_fence_get_stub();
-
-	amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
-
-	mutex_lock(&entity->lock);
-	while (cursor.remaining) {
-		struct dma_fence *next = NULL;
-		u64 size;
-
-		if (amdgpu_res_cleared(&cursor)) {
-			amdgpu_res_next(&cursor, cursor.size);
-			continue;
-		}
-
-		/* Never clear more than 256MiB at once to avoid timeouts */
-		size = min(cursor.size, 256ULL << 20);
-
-		r = amdgpu_ttm_map_buffer(entity, &bo->tbo, bo->tbo.resource, &cursor,
-					  0, false, &size, &addr);
-		if (r)
-			goto err;
-
-		r = amdgpu_ttm_fill_mem(adev, entity, 0, addr, size, resv,
-					&next, true,
-					AMDGPU_KERNEL_JOB_ID_TTM_CLEAR_BUFFER);
-		if (r)
-			goto err;
-
-		dma_fence_put(*fence);
-		*fence = next;
-
-		amdgpu_res_next(&cursor, size);
-	}
-err:
-	mutex_unlock(&entity->lock);
-
-	return r;
-}
-
 int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
    	       struct amdgpu_bo *bo,
    	       uint32_t src_data,
    	       struct dma_resv *resv,
-		       struct dma_fence **f,
+		       struct dma_fence **out_fence,
+		       bool consider_clear_status,
    	       u64 k_job_id)
 {
    struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
@@ -2659,6 +2608,11 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
    	struct dma_fence *next;
    	uint64_t cur_size, to;
+		if (consider_clear_status && amdgpu_res_cleared(&dst)) {
+			amdgpu_res_next(&dst, dst.size);
+			continue;
+		}
+
    	/* Never fill more than 256MiB at once to avoid timeouts */
    	cur_size = min(dst.size, 256ULL << 20);
@@ -2680,9 +2634,7 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
    }
 error:
    mutex_unlock(&entity->lock);
-	if (f)
-		*f = dma_fence_get(fence);
-	dma_fence_put(fence);
+	*out_fence = fence;
    return r;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index a6249252948b..436a3e09a178 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -187,14 +187,12 @@ int amdgpu_copy_buffer(struct amdgpu_device *adev,
    	       struct dma_resv *resv,
    	       struct dma_fence **fence,
    	       bool vm_needs_flush, uint32_t copy_flags);
-int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
-			    struct dma_resv *resv,
-			    struct dma_fence **fence);
 int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
    	       struct amdgpu_bo *bo,
    	       uint32_t src_data,
    	       struct dma_resv *resv,
-		       struct dma_fence **f,
+		       struct dma_fence **out_fence,
+		       bool consider_clear_status,
    	       u64 k_job_id);
 struct amdgpu_ttm_buffer_entity *amdgpu_ttm_next_clear_entity(struct amdgpu_device *adev);
-- 
2.43.0


    