RDMA/core: Allow the ioctl layer to abort a fully created uobject

While creating a uobject every create reaches a point where the uobject is
fully initialized. For ioctls that go on to copy_to_user this means they
need to open code the destruction of a fully created uobject - ie the
RDMA_REMOVE_DESTROY sort of flow.

Open coding this creates bugs, eg the CQ does not properly flush the
events list when it does its error unwind.

Provide a uverbs_finalize_uobj_create() function which indicates that the
uobject is fully initialized and that abort should call to destroy_hw to
destroy the uobj->object and related.

Methods can call this function if they go on to have error cases after
setting uobj->object. Once done those error cases can simply do return,
without an error unwind.

Link: https://lore.kernel.org/r/20200519072711.257271-2-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/devx.c

@@ -2218,14 +2218,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_UMEM_REG)(
 	obj->mdev = dev->mdev;
 	uobj->object = obj;
 	devx_obj_build_destroy_cmd(cmd.in, cmd.out, obj->dinbox, &obj->dinlen, &obj_id);
-	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_OUT_ID, &obj_id, sizeof(obj_id));
-	if (err)
-		goto err_umem_destroy;
+	uverbs_finalize_uobj_create(attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_HANDLE);
 
-	return 0;
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_OUT_ID, &obj_id,
+			     sizeof(obj_id));
+	return err;
 
-err_umem_destroy:
-	mlx5_cmd_exec(obj->mdev, obj->dinbox, obj->dinlen, cmd.out, sizeof(cmd.out));
 err_umem_release:
 	ib_umem_release(obj->umem);
 err_obj_free:

drivers/infiniband/hw/mlx5/main.c

@@ -6187,26 +6187,20 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_VAR_OBJ_ALLOC)(
 	mmap_offset = mlx5_entry_to_mmap_offset(entry);
 	length = entry->rdma_entry.npages * PAGE_SIZE;
 	uobj->object = entry;
+	uverbs_finalize_uobj_create(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_HANDLE);
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_OFFSET,
 			     &mmap_offset, sizeof(mmap_offset));
 	if (err)
-		goto err;
+		return err;
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_PAGE_ID,
 			     &entry->page_idx, sizeof(entry->page_idx));
 	if (err)
-		goto err;
+		return err;
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_VAR_OBJ_ALLOC_MMAP_LENGTH,
 			     &length, sizeof(length));
-	if (err)
-		goto err;
-
-	return 0;
-
-err:
-	rdma_user_mmap_entry_remove(&entry->rdma_entry);
 	return err;
 }
 
@@ -6320,26 +6314,20 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_UAR_OBJ_ALLOC)(
 	mmap_offset = mlx5_entry_to_mmap_offset(entry);
 	length = entry->rdma_entry.npages * PAGE_SIZE;
 	uobj->object = entry;
+	uverbs_finalize_uobj_create(attrs, MLX5_IB_ATTR_UAR_OBJ_ALLOC_HANDLE);
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_UAR_OBJ_ALLOC_MMAP_OFFSET,
 			     &mmap_offset, sizeof(mmap_offset));
 	if (err)
-		goto err;
+		return err;
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_UAR_OBJ_ALLOC_PAGE_ID,
 			     &entry->page_idx, sizeof(entry->page_idx));
 	if (err)
-		goto err;
+		return err;
 
 	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_UAR_OBJ_ALLOC_MMAP_LENGTH,
 			     &length, sizeof(length));
-	if (err)
-		goto err;
-
-	return 0;
-
-err:
-	rdma_user_mmap_entry_remove(&entry->rdma_entry);
 	return err;
 }
 

drivers/infiniband/hw/mlx5/qos.c

@@ -69,17 +69,14 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_PP_OBJ_ALLOC)(
 	if (err)
 		goto err;
 
-	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_PP_OBJ_ALLOC_INDEX,
-			     &pp_entry->index, sizeof(pp_entry->index));
-	if (err)
-		goto clean;
-
 	pp_entry->mdev = dev->mdev;
 	uobj->object = pp_entry;
-	return 0;
+	uverbs_finalize_uobj_create(attrs, MLX5_IB_ATTR_PP_OBJ_ALLOC_HANDLE);
+
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_PP_OBJ_ALLOC_INDEX,
+			     &pp_entry->index, sizeof(pp_entry->index));
+	return err;
 
-clean:
-	mlx5_rl_remove_rate_raw(dev->mdev, pp_entry->index);
 err:
 	kfree(pp_entry);
 	return err;