RE: [PATCH rdma-next v2 01/13] IB/uverbs: Add an ib_uobject getter to ioctl() infrastructure

[Ruhl, Michael J]

>-----Original Message-----
>From: Jason Gunthorpe [mailto:j...@mellanox.com]
>Sent: Tuesday, May 29, 2018 4:21 PM
>To: Ruhl, Michael J <michael.j.r...@intel.com>
>Cc: Leon Romanovsky <l...@kernel.org>; Doug Ledford
><dledf...@redhat.com>; Leon Romanovsky <leo...@mellanox.com>; RDMA
>mailing list <linux-r...@vger.kernel.org>; Boris Pismenny
><bor...@mellanox.com>; Matan Barak <mat...@mellanox.com>; Raed
>Salem <ra...@mellanox.com>; Yishai Hadas <yish...@mellanox.com>; Saeed
>Mahameed <sae...@mellanox.com>; linux-netdev
><netdev@vger.kernel.org>
>Subject: Re: [PATCH rdma-next v2 01/13] IB/uverbs: Add an ib_uobject getter
>to ioctl() infrastructure
>
>On Tue, May 29, 2018 at 07:31:22PM +0000, Ruhl, Michael J wrote:
>> >-   struct ib_uverbs_destroy_cq_resp resp;
>> >    struct ib_uobject *uobj =
>> >-           uverbs_attr_get(attrs,
>> >UVERBS_ATTR_DESTROY_CQ_HANDLE)->obj_attr.uobject;
>> >-   struct ib_ucq_object *obj = container_of(uobj, struct ib_ucq_object,
>> >-                                            uobject);
>> >+           uverbs_attr_get_uobject(attrs,
>> >UVERBS_ATTR_DESTROY_CQ_HANDLE);
>> >+   struct ib_uverbs_destroy_cq_resp resp;
>> >+   struct ib_ucq_object *obj;
>> >    int ret;
>> >
>> >+   if (IS_ERR(uobj))
>> >+           return PTR_ERR(uobj);
>> >+
>>
>> I remember a conversation that if an method attribute was mandatory, that
>you did not need to
>> test the uobj for error (since it was checked in the infrastructure).
>
>Yes.
>
>> Is this error check necessary?
>
>No
>
>But there is no way to check one way or the other at compile time
>right now, and omitting the check makes smatch mad.

Is smatch going to get mad at (same patch):

diff --git a/drivers/infiniband/core/uverbs_std_types_flow_action.c 
b/drivers/infiniband/core/uverbs_std_types_flow_action.c
index b4f016dfa23d..a7be51cf2e42 100644
--- a/drivers/infiniband/core/uverbs_std_types_flow_action.c
+++ b/drivers/infiniband/core/uverbs_std_types_flow_action.c
@@ -320,7 +320,7 @@ static int 
UVERBS_HANDLER(UVERBS_METHOD_FLOW_ACTION_ESP_CREATE)(struct ib_device
                return ret;

        /* No need to check as this attribute is marked as MANDATORY */
-       uobj = uverbs_attr_get(attrs, 
UVERBS_ATTR_FLOW_ACTION_ESP_HANDLE)->obj_attr.uobject;
+       uobj = uverbs_attr_get_uobject(attrs, 
UVERBS_ATTR_FLOW_ACTION_ESP_HANDLE);
        action = ib_dev->create_flow_action_esp(ib_dev, &esp_attr.hdr, attrs);
        if (IS_ERR(action))
                return PTR_ERR(action);
@@ -350,7 +350,7 @@ static int 
UVERBS_HANDLER(UVERBS_METHOD_FLOW_ACTION_ESP_MODIFY)(struct ib_device
        if (ret)
                return ret;

-       uobj = uverbs_attr_get(attrs, 
UVERBS_ATTR_FLOW_ACTION_ESP_HANDLE)->obj_attr.uobject;
+       uobj = uverbs_attr_get_uobject(attrs, 
UVERBS_ATTR_FLOW_ACTION_ESP_HANDLE);
        action = uobj->object;

?

If not,

Reviewed-by: Michael J. Ruhl <michael.j.r...@intel.com>

Thanks,

Mike

>We need some more patches to be able to safely omit the check...
>
>Jason