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>

1 files changed, 3 insertions, 9 deletions

diff --git a/drivers/infiniband/core/uverbs_std_types_mr.c b/drivers/infiniband/core/uverbs_std_types_mr.c
index c1286a52dc84..a2722ef8496e 100644
--- a/drivers/infiniband/core/uverbs_std_types_mr.c
+++ b/drivers/infiniband/core/uverbs_std_types_mr.c
@@ -136,21 +136,15 @@ static int UVERBS_HANDLER(UVERBS_METHOD_DM_MR_REG)(
 
 	uobj->object = mr;
 
+	uverbs_finalize_uobj_create(attrs, UVERBS_ATTR_REG_DM_MR_HANDLE);
+
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_REG_DM_MR_RESP_LKEY, &mr->lkey,
 			     sizeof(mr->lkey));
 	if (ret)
-		goto err_dereg;
+		return ret;
 
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_REG_DM_MR_RESP_RKEY,
 			     &mr->rkey, sizeof(mr->rkey));
-	if (ret)
-		goto err_dereg;
-
-	return 0;
-
-err_dereg:
-	ib_dereg_mr_user(mr, uverbs_get_cleared_udata(attrs));
-
 	return ret;
 }