drm/amdgpu: Move dmabuf attach/detach to backend_(un)bind

The dmabuf attachment should be updated by moving the SG BO to DOMAIN_CPU
and back to DOMAIN_GTT. This does not necessarily invoke the
populate/unpopulate callbacks. Do this in backend_bind/unbind instead.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Oak Zeng <Oak.Zeng@amd.com>
Acked-by: Ramesh Errabolu <Ramesh.Errabolu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -587,9 +587,6 @@ kfd_mem_dmaunmap_dmabuf(struct kfd_mem_attachment *attachment)
 
 	amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
 	ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
-	/* FIXME: This does not guarantee that amdgpu_ttm_tt_unpopulate is
-	 * called
-	 */
 }
 
 static void

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

@@ -907,7 +907,23 @@ static int amdgpu_ttm_backend_bind(struct ttm_device *bdev,
 			DRM_ERROR("failed to pin userptr\n");
 			return r;
 		}
+	} else if (ttm->page_flags & TTM_PAGE_FLAG_SG) {
+		if (!ttm->sg) {
+			struct dma_buf_attachment *attach;
+			struct sg_table *sgt;
+
+			attach = gtt->gobj->import_attach;
+			sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+			if (IS_ERR(sgt))
+				return PTR_ERR(sgt);
+
+			ttm->sg = sgt;
 		}
+
+		drm_prime_sg_to_dma_addr_array(ttm->sg, gtt->ttm.dma_address,
+					       ttm->num_pages);
+	}
+
 	if (!ttm->num_pages) {
 		WARN(1, "nothing to bind %u pages for mreg %p back %p!\n",
 		     ttm->num_pages, bo_mem, ttm);
@@ -1034,8 +1050,15 @@ static void amdgpu_ttm_backend_unbind(struct ttm_device *bdev,
 	int r;
 
 	/* if the pages have userptr pinning then clear that first */
-	if (gtt->userptr)
+	if (gtt->userptr) {
 		amdgpu_ttm_tt_unpin_userptr(bdev, ttm);
+	} else if (ttm->sg && gtt->gobj->import_attach) {
+		struct dma_buf_attachment *attach;
+
+		attach = gtt->gobj->import_attach;
+		dma_buf_unmap_attachment(attach, ttm->sg, DMA_BIDIRECTIONAL);
+		ttm->sg = NULL;
+	}
 
 	if (!gtt->bound)
 		return;
@@ -1122,23 +1145,8 @@ static int amdgpu_ttm_tt_populate(struct ttm_device *bdev,
 		return 0;
 	}
 
-	if (ttm->page_flags & TTM_PAGE_FLAG_SG) {
-		if (!ttm->sg) {
-			struct dma_buf_attachment *attach;
-			struct sg_table *sgt;
-
-			attach = gtt->gobj->import_attach;
-			sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
-			if (IS_ERR(sgt))
-				return PTR_ERR(sgt);
-
-			ttm->sg = sgt;
-		}
-
-		drm_prime_sg_to_dma_addr_array(ttm->sg, gtt->ttm.dma_address,
-					       ttm->num_pages);
+	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
 		return 0;
-	}
 
 	return ttm_pool_alloc(&adev->mman.bdev.pool, ttm, ctx);
 }
@@ -1162,15 +1170,6 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_device *bdev,
 		return;
 	}
 
-	if (ttm->sg && gtt->gobj->import_attach) {
-		struct dma_buf_attachment *attach;
-
-		attach = gtt->gobj->import_attach;
-		dma_buf_unmap_attachment(attach, ttm->sg, DMA_BIDIRECTIONAL);
-		ttm->sg = NULL;
-		return;
-	}
-
 	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
 		return;